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International Dairy Federatio

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n Internationale de Laiterie

Canada

International Dairy Federatio

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n Internationale de Laiterie

IDF Dairy Science and Technology Week / Novalait Technological Forum

2008Q u e b e cMay, 12 - 16

C a n a d a

ProgramDetailed

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IDF DAIRY SCIENCE AND TECHNOLOGY WEEK 2008

Organizing Committee Paul Paquin Chairman, Vice-president FIL-IDF Canada

Pierre Doyle Assistant Director, Dairy sector, Agriculture and Agri-Food Canada, Ottawa, Ontario, CANADA

Sylvie Turgeon Director, STELA Dairy Research Center, Laval University, Québec, CANADA

Jacques Rolland Research and Development, Agropur Cooperative, Québec, CANADA

Gaétan Paquette Senior Director, Finance & Operations, Canadian Dairy Commission, Ottawa, Ontario, CANADA

Andrée Lagacé Liaison Officer, STELA Dairy Research Center, Laval University, Québec, CANADA

Danielle Rivard General Manager, Novalait inc., Québec, CANADA

Élise Gosselin Coordinator, Novalait inc., Québec, CANADa

International Scientific Committee Sylvie Turgeon Chairman, STELA Dairy Research Center, Laval University,

Québec, CANADA

Milena Corredig University of Guelph, Guelph, Ontario, CANADA

Daniel St-Gelais Agriculture and Agri-Food Canada, FRDC, Saint-Hyacinthe, Québec, CANADA

Ulrich Kulozik Munchën University, Munchën, GERMANY

Geoff Smithers Food Science Australia, CSIRO, AUSTRALIA

Philip S. Tong California Polytechnic State University, USA

Michael Gänzle University of Alberta, Alberta, CANADA

Paul Jelen University of Alberta, Alberta, CANADA

Michel Pouliot Agropur Cooperative, Québec, CANADA

PROGRAM AT A GLANCE

MONDAY, MAY 12 TUESDAY, MAY 13 WEDNESDAY, MAY 14 THURSDAY, MAY 15 FRIDAY, MAY 16

A.M.

NOVALAIT TECHNOLOGICAL FORUM

SESSION 1

Health Properties of Milk and Dairy products

SESSION 3

Microbial Quality of Milk and New Tools

TECHNICAL VISIT:

Kerry Ingredients Manufacture IDF Standing Committee on Dairy Science and Technology Meeting

TECHNICAL VISIT:

Institute of Nutraceuticals and Functional Foods (INAF)

FIL-IDF Canada Annual Meeting

LUNCH AND POSTER SESSION



P.M. NOVALAIT TECHNOLOGICAL FORUM

IDF Action Team Meetings on Dairy Science and Technology

SESSION 2

Process-Induced Interactions: Control to Optimize Quality and Delivery of Health Benefits

SESSION 4

Alternatives to Thermal Processing: Impact on Product Quality

FIL-IDF Canada Annual Meeting

AWARDINGS POSTER SESSION POSTER SESSION

EVENING WINE AND CHEESE Greeting from Quebec Minister of Agriculture, Fisheries and Food

CLOSING DINNER AND MUSICAL SHOW

The CAPITOLE DE QUÉBEC

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Monday, May 12, 2008 Novalait Technological Forum

9:00 a.m. FORUM OPENING Ms. Lorraine BÉDARD, President of Novalait Inc. Ms. Danielle RIVARD, General Manager of Novalait Inc. 9:15 a.m. PRESENTATION OF RESULTS AND IMPACTS OF PROJECTS SUPPORTED BY NOVALAIT INC.

Moderator: Mr. René GRIMARD, Agropur coopérative

9:15 a.m. Control of Oxidation-Reduction Potential in Dairy Processing / Michel BRITTEN

9:35 a.m. A New Life for Old Starters / Jean-Christophe VUILLEMARD

9 :55 a.m. Control of Cheese Milk Technological Aptitudes and Monitoring of Microbiological Activity with Molecular Methods / Gisèle LAPOINTE

10:15 a.m. Impact Study of Milk Trans Fats on Cardiovascular Risk / Benoît LAMARCHE 10:35 a.m. BREAK – POSTER SESSION AT THE “CARREFOUR DE LA RELÈVE TECHNOLOGIQUE” 11:00 a.m. PRESENTATION OF RESULTS AND IMPACTS OF PROJECTS SUPPORTED BY NOVALAIT INC.

Moderator: Mr. Gilbert RIOUX, FPLQ 11:00 a.m. Butyric Spores on the Farm / Pascal DROUIN

11:20 a.m. Bunker Silos for Grass and Corn / Roger THÉRIAULT

11:40 a.m. Hay for Dry Cow: DCAD, the solution from Québec! / Sophie LAVALLÉE 12:00 p.m. LUNCH 1:30 p.m. POSTER SESSION AT THE “CARREFOUR DE LA RELÈVE TECHNOLOGIQUE” 2:00 p.m. PRESENTATION OF RESULTS AND IMPACTS OF PROJECTS SUPPORTED BY NOVALAIT INC.

Moderator: Mr. François MARCIL, Laiterie Chalifoux / Les fromages Riviera 2:00 p.m. Breeding and Growth Conditions of Replacement Livestock in Quebec / Roger CUE

2:20 p.m. Folic Acid, Vitamin B12 and Methionine: Effects on Metabolism and Lactation Performance / Christiane GIRARD

2:40 p.m. PREMIUM MILK INNOVATION SPECIAL PRESENTATION 2:40 p.m. Premium Milk Innovation Project

2007-2015 Scientific and Technological Roadmap Ms. Élise GOSSELIN, Manager of the Premium Milk Innovation Project

3:10 p.m. Action Plan for Further Steps Ms. Danielle RIVARD, General Manager of Novalait Inc.

3:30 p.m. AWARDING OF THE “PRIX D’EXCELLENCE DE LA RELÈVE TECHNOLOGIQUE”

Ms. Lorraine BÉDARD, President of Novalait Inc. and Mr. Pierre Prémont, CEO of Quebec Fund for Research on Nature and Technologies (FQRNT)

3:45 P.M. AWARDING OF THE 2008 MASTER’S EXCELLENCE SCHOLARSHIP FROM THE CANADIAN

DAIRY COMMISSION SCHOLARSHIP PROGRAM, IN COLLABORATION WITH NOVALAIT INC.

Ms. Lorraine BÉDARD, President of Novalait Inc. and Mr. Gilles Froment, Senior Director, Policy and Corporate Affairs of the Canadian Dairy Commission

4:00 p.m. CLOSING ADDRESS

Ms. Lorraine BÉDARD, President of Novalait Inc. 4:15 p.m. COCKTAIL AT THE “CARREFOUR DE LA RELÈVE TECHNOLOGIQUE” / IDF SCIENCE &

TECHNOLOGY WEEK

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Forum technologique Novalait

Le lundi 12 mai 2008

9 h 15

Régulation électrochimique du potentiel d’oxydoréduction du lait : impact sur l’efficacité de transformation et la qualité des produits

Michel BRITTEN1, Claude P. CHAMPAGNE1, Patrick FUSTIER1, Hélène J. GIROUX1,

Monica ARAYA2, Paul ANGERS2, Laurent BAZINET2, Yves POULIOT2, Jean-Christophe VUILLEMARD2, Jean-Marc CHAPUZET3, Jean LESSARD3,

Marie-Pierre BOLDUC2, Michèle FILION2, Sanaz HARATIFAR2 et Arnaud SCHREYER2 1Agriculture et Agroalimentaire Canada, Centre de recherche et de développement sur les aliments

(CRDA), 2Centre de recherche STELA – Institut des nutraceutiques et des aliments fonctionnels (INAF), Université Laval, 3Université de Sherbrooke

L’électroréduction conduit à l’abaissement du potentiel d’oxydoréduction (POR) et de la concentration en oxygène dissous du lait; l’effet dépend de l’intensité et de la durée du traitement. L’électroréduction améliore sensiblement la coagulation à la présure des laits chauffés et la stabilité à haute température. Le traitement n’a pas d’impact sur le développement des flores contaminantes, mais favorise la survie de certaines souches de bifidobactéries. Les effets de l’électroréduction sur le lait s’expliquent essentiellement par la diminution de la concentration en oxygène dissous. La remontée rapide du POR après le traitement, suggère une faible capacité tampon du lait électroréduit et le rééquilibrage lent des réactions électrochimiques.

9 h 35

Caractérisation des activités biologiques et du potentiel technologique de souches bactériennes isolées de ferments lactiques naturels

Jean-Christophe VUILLEMARD1, Nadine LACROIX1, Diane GAGNON1, Jocelyn LESSARD1, Daniel SAINT-GELAIS2, Claude P. CHAMPAGNE2, Jacinthe FORTIN2 et Gaétan BÉLANGER2 1Centre de recherche STELA – Institut sur les nutraceutiques et les aliments fonctionnels (INAF),

Université Laval, 2Agriculture et Agroalimentaire Canada, Centre de recherche et de développement sur les aliments (CRDA)

Treize ferments lactiques traditionnels utilisés dans les années soixante ont démontré la capacité de produire en quantité importante une grande variété de composés aromatiques. La production de composés aromatiques, comme le diacétyle, a été augmentée par addition de citrate dans les milieux de préparation des ferments et par le contrôle du pH de propagation. Neuf souches de deux ferments ont également montré une forte production d’acide gamma-amino-butyrique (GABA), un composé qui possède des propriétés antihypertensives et calmantes. L’utilisation combinée des 3 bactéries Lactococcus lactis ssp lactis biovar diacetylactis 74311, S. thermophilus et de Lc. cremoris a permis d’améliorer la flaveur du fromage en grains tout en réduisant la post-acidification.

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9 h 55

Pour un meilleur contrôle des aptitudes technologiques du lait de fromagerie grâce au développement de méthodes moléculaires du suivi

et de la quantification de l'activité microbiologique

Gisèle LAPOINTE1, Denis ROY1 et Daniel ST-GELAIS2

1Centre de recherche STELA - Institut des nutraceutiques et des aliments fonctionnels (INAF), Université Laval, 2Agriculture et Agroalimentaire Canada, CRDA

Le présent projet vise à apporter des réponses aux préoccupations des consommateurs, aux besoins de l’industrie et aux exigences réglementaires en matière de qualité microbiologique du lait et des produits laitiers. Le premier objectif du projet était d’évaluer des méthodes de contrôle permettant de prévenir la dégradation de l'aptitude technologique du lait. Les résultats démontrent que le traitement du lait au dioxyde de carbone ou par la microfiltration peut être utilisé efficacement pour conserver du lait cru pendant 9 jours à 4 °C. Les fromages produits avec ces laits traités après 9 jours de conservation étaient de qualité comparable à ceux produits avec du lait frais de 2 jours. Le deuxième objectif de ce projet était de mettre au point des méthodes moléculaires afin d’étudier l’écologie microbienne des laits avant et après l’application des traitements. Les méthodes ont permis de déterminer la dynamique et la composition en espèces microbiennes (appelé le microbiote) du lait, sans culture ni isolement préalable des bactéries. Le troisième objectif du projet était de développer une méthode pour détecter des déviations dans le comportement des ferments lors de la transformation du lait. Lors du procédé de fabrication fromagère, la méthode a permis de déterminer la contribution relative de chacune des trois souches de Lactococcus lactis ssp. cremoris à l’association en culture mixte et de suivre la modification de l’activité des ferments selon le traitement. Les connaissances et les techniques sont ainsi disponibles afin d’améliorer la rentabilité de la production et de la transformation en permettant d’augmenter le temps de conservation du lait cru avant sa transformation et en identifiant les facteurs de risque qui peuvent compromettre sa qualité.

10 h 15 Étude de l’impact des gras trans d’origine laitière sur le risque cardiovasculaire

Benoît LAMARCHE1, Paul PAQUIN1, Yvan CHOUINARD1, Simone LEMIEUX2, Amélie CHAREST2, Johanne MARIN2, Georges COUSINEAU2, Annie MOTARD-BÉLANGER1,

Geneviève GRENIER2, Élise CLERC2, Danielle AUBIN2, Claire JULIEN2, Sandra GAGNON2 Stéphanie OUELLET2 et Patrick COUTURE3

1Centre de recherche STELA - Institut des nutraceutiques et des aliments fonctionnels (INAF), Université Laval, 2INAF, Université Laval, 3INAF et CHUQ

Plusieurs études épidémiologiques et cliniques ont associé la consommation d’AGT de sources industrielles à une augmentation du risque de maladies cardiovasculaires (MCV). D’autre part, l’association entre les acides gras trans (AGT) d’origine naturelle que l’on retrouve principalement dans les produits laitiers et le risque cardiovasculaire est beaucoup moins bien documentée. L’objectif de ce projet était de comparer, dans un contexte nutritionnel contrôlé de façon optimale, l’impact des AGT industriels et naturels sur les facteurs de risque cardiovasculaire. L’étude clinique à double insu en chassé-croisé impliquait 38 hommes en santé qui ont consommé 4 diètes comportant différents niveaux d’AGT naturels et industriels. Les facteurs de risque cardiovasculaires mesurés à la fin de chacune des diètes ont été comparés. Les résultats ont démontré que les concentrations plasmatiques de LDL étaient plus élevées à la suite de la diète très élevée en AGT naturels (10,2 g/2 500 kcal) par rapport à la diète témoin (p=0,03). La diète modérée en AGT naturels (4,2 g/2 500 kcal) n’a toutefois induit aucun changement significatif dans les facteurs de risque cardiovasculaires comparativement à la diète témoin. Cette première étude nutritionnelle contrôlée démontre que la consommation d’AGT naturels pourrait avoir des effets néfastes sur le profil lipidique, mais que les apports correspondant à la limite maximale pouvant être consommée par la population semblent avoir des effets neutres sur les lipoprotéines plasmatiques.

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11 h 00 Développement de stratégies pour diminuer les spores butyriques dans le lait cru

obtenu de vaches nourries à l’ensilage

Pascal DROUIN1, Carole LAFRENIÈRE2, Hani ANTOUN3, Patrice DION3, Gisèle LAPOINTE3, Marie- Claude JULIEN3 et Annie CHAMPAGNE3

1Université du Québec en Abitibi-Témiscamingue, 2Unité de recherche et de développement en agroalimentaire, Université du Québec en Abitibi-Témiscamingue (UQAT), 3INAF, Université Laval

La contamination du lait par les spores butyriques résistantes à la pasteurisation peut entraîner des pertes économiques de près de 10 millions de dollars/année pour l’industrie fromagère au Québec. Des recherches indiquent que ce type de contamination est en étroite relation avec l’utilisation d’ensilage dans l’alimentation des troupeaux. L’approche proposée est d’étudier l’écologie des Clostridium dans la chaîne de production du lait à la ferme. Parallèlement à ces essais, différentes stratégies sont explorées pour inhiber le développement des spores. La diminution des spores dans l’environnement de l’étable devrait se traduire par une meilleure qualité microbiologique du lait permettant ainsi de réduire les pertes à l’usine. Les résultats ont permis de démontrer qu’il y a deux profils spécifiques aux Clostridium pour le lait cru sur les fermes. Ces profils ne sont pas constants pour une même ferme d’une année à l’autre. Les résultats de dénombrement pour les ensilages de maïs indiquent qu’ils contiennent en moyenne 100 fois plus de spores de Clostridium que les ensilages d’herbe. Par ailleurs, dans les ensilages de maïs, la production d’acide butyrique caractéristique du développement des Clostridium est très faible. Dans les silos expérimentaux préparés à partir de parcelles fertilisées par différentes fumures organiques, les clostridies se sont développées de façon plus importante dans les ensilages de fléole des prés que dans les ensilages avec un mélange luzerne/fléole, et ce, malgré le faible nombre de Clostridium lors de l’entrée au silo. Une bactérie lactique produisant une substance ayant une activité anti-clostridiale a été identifiée. L’efficacité de cette bactérie a été comparée en silos expérimentaux à un inoculant commercial ainsi qu’à un produit acidifiant additionné de nitrites.

11 h 20

Ensilages en silos couloir : gestion du remplissage et développement d’une mesure directe de la matière sèche lors de la préparation

des rations totales mélangées (RTM) Roger THÉRIAULT1, Philippe SAVOIE2, André AMYOT3 et Luc COUTURE4

1FSAA, Département des sols et de génie agroalimentaire, Université Laval, 2Agriculture et Agroalimentaire Canada / Centre de recherche et de développement sur les sols et les grandes

cultures (CRDSGC), Université Laval, 3Institut de recherche et développement en agroenvironnement, 4Agriculture et Agroalimentaire Canada, CRDSGC

Au Québec, environ 60 % de l’herbe cultivée (sur une superficie de 700 000 ha produisant 4 Mt de matière sèche par an) et 100 % du maïs-ensilage (environ 40 000 ha et 600 000 t MS) sont conservés en ensilage, soit 3,0 Mt principalement en silos tour. Au cours des dernières années, le silo couloir est apparu comme une alternative valable au silo tour. Il pourrait servir à entreposer près de la moitié des ensilages au Québec d’ici 15 ans. Une bonne conservation en silo couloir exige toutefois une régie attentive afin de minimiser les pertes et assurer une alimentation de qualité. Une meilleure information technique (construction, couverture, compactage, reprise) pourrait apporter des gains de productivité de l’ordre de 4 à 8 $/t MS, soit un potentiel de 6 à 12 millions $ par année pour les producteurs laitiers quand les silos couloir deviendront plus omniprésents. Le projet de recherche avait quatre objectifs : 1) préciser la relation entre la densité, la couverture et les pertes; 2) établir le risque de contamination microbiologique selon la densité et la reprise; 3) établir une relation entre la densité et la régie lors du remplissage; 4) proposer un système de mesure instantanée de l’humidité des ensilages pour la préparation de RTM plus précise. Un aspect novateur du projet était l’intégration de plusieurs éléments de régie et de choix techniques entre le champ et la mangeoire pour optimiser l’utilisation du silo couloir.

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11 h 40

Mise à l’échelle de la production et de l’utilisation de foin destiné à la vache tarie

Sophie LAVALLÉE1, Hélène BRASSARD1, Alain FOURNIER2, Guy ALLARD3, Doris PELLERIN3 et Edith CHARBONNEAU3

1Agrinova, Centre de services Montérégie, 2MAPAQ Centre-du-Québec, 3 FSAA, Département des sciences animales, Université Laval

Ce projet consistait en une mise à l’échelle, des résultats d’une recherche scientifique sur la « production de fourrages adaptés aux besoins de la vache tarie » réalisée de 2002 à 2005 par l’Université Laval. Il visait à accélérer l’utilisation de cette technique novatrice par l’ensemble des fermes laitières du Québec. La fièvre vitulaire est la forme clinique d’un désordre métabolique majeur en production laitière, soit l’hypocalcémie. Les vaches atteintes de fièvre vitulaire produisent 14 % moins de lait lors de la lactation qui suit. Il a été estimé que chaque cas coûte au moins 500 $ en frais vétérinaire et perte de productivité. Pour réussir la période de transition, une ration à faible différence alimentaire cations-anions (DACA) doit être servie quelques semaines avant le vêlage. Le projet visait à valider que la production de foin à faible DACA et son intégration à la ration de la vache tarie, était possible et représentait une approche préventive et efficace pour réduire l’incidence de la fièvre vitulaire. Dix entreprises laitières des régions du Centre-du-Québec et de la Montérégie ont été sélectionnées pour leur potentiel à produire un fourrage à faible DACA. À l’été 2006, les producteurs ont été accompagnés dans la production de foin afin de répondre aux besoins fourragers des vaches taries. Par la suite, la DACA de la ration des vaches taries a été abaissée entre 0 et 50 mÉq/kg MS, soit en y intégrant le foin à faible DACA (groupe chloré), soit en servant le fourrage habituel (groupe témoin). Une mesure de l’efficacité du foin a été effectuée grâce à la prise du pH urinaire avant le vêlage et à des observations comportementales. Les coûts de production du foin à faible DACA ont été comptabilisés afin de mesurer les impacts économiques d’une telle pratique sur la ferme. Actuellement, au Québec, peu d’entreprises laitières se prévalent de cette approche alimentaire novatrice pour réduire l’incidence de la fièvre vitulaire. Il s’agit là d’une excellente stratégie pour les producteurs laitiers d’utiliser un moyen simple, efficace et naturel et qui s’ajoute aux ingrédients déjà en place pour réussir une meilleure transition.

12 h 00 - Dîner

13 h 30 - Session d’affiches au « Carrefour de la relève technologique »

Salles Crémazie-Garneau

14 h 00

Conditions d’élevage et croissance des animaux de remplacement du Québec

Roger I. CUE1, Anne-Marie DE PASSILLÉ2, Jeffrey RUSHEN2, Doris PELLERIN3, Daniel LEFEBVRE4, René LACROIX5 et Kevin Michael WADE5

1Département des Sciences animales, Université McGill, 2Agriculture et Agroalimentaire Canada, 3FSAA, Département des sciences animales, Université Laval, 4Valacta, 5Université McGill

Ce projet aborde la problématique de la croissance sous-optimale des animaux de remplacement en production laitière au Québec, un problème entraînant des pertes estimées à environ 40 millions de dollars pour l’ensemble des producteurs. Le premier aspect novateur de ce projet est une meilleure connaissance des profils d’élevage des génisses au Québec, et l’étude des relations entre les profils d’élevage et la croissance des animaux. Son deuxième aspect novateur est le développement d’un modèle de croissance des génisses basé sur une approche de modèles mixtes et aléatoires.

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14 h 20

Interactions acide folique – vitamine B12 – méthionine : effets sur le métabolisme hépatique et la productivité des vaches laitières

Christiane L. GIRARD1, Hélène LAPIERRE1, Jacques MATTE1, André DESROCHERS2, Marie-France PALIN1, Carole THIVIERGE3

1Agriculture et Agroalimentaire Canada, Centre de recherche et de développement sur le bovin laitier et le porc (CRDBLP), 2Université de Montréal, 3Université Laval

Il est probable qu'une augmentation de la production laitière augmente les besoins en acide folique et en vitamine B12, ces vitamines intervenant dans les voies importantes des métabolismes protéique et énergétique. Un apport insuffisant diminuera l'efficacité des voies métaboliques majeures, augmentant les coûts de production. Les animaux ont un besoin élevé en groupes méthyls, par exemple, pour synthétiser les membranes cellulaires et celles entourant les gras du lait et stocker l'énergie dans le muscle. Chez les animaux monogastriques, ces groupes méthyls sont fournis par la méthionine, la choline et la créatine d'origine alimentaire. Par contre chez les ruminants, l'alimentation est pauvre en créatine et méthionine, tandis que la choline est détruite par la microflore ruminale. Pour faire face à l'importante demande en groupes méthyls, les ruminants doivent donc compter synthétiser ces groupes via le métabolisme des folates et de la vitamine B12. De plus, la vitamine B12 joue un rôle essentiel dans la gluconéogenèse. Le présent projet visait donc à étudier les effets d'une augmentation des apports en acide folique et vitamine B12, en présence d'apports adéquats ou insuffisants de méthionine, sur les performances de lactation et les variables sanguines et hépatiques, indicatrices des voies métaboliques sollicitées pendant les 16 premières semaines de lactation. Les résultats de ces travaux ont permis de démontrer que c’est au cours des premières semaines suivant le vêlage que les vaches bénéficient le plus des suppléments de vitamines. Le supplément combiné d’acide folique et vitamine B12 a augmenté la production de lait et de composantes du lait, surtout en début de lactation, mais cette réponse n’a pas été modifiée par les apports en méthionine. Les suppléments de vitamine B12 ont augmenté de 50 % le transfert de cette vitamine dans le lait, augmentation présentant un intérêt nutritionnel non négligeable pour les enfants en bas âge, les femmes enceintes et allaitantes et surtout, les personnes âgées.

14 h 40 – Présentation spéciale Premium Lait Innovation Elise Gosselin, directrice du projet

Danielle Rivard, directrice générale, Novalait inc. 15 h 30 – Remise des « Prix d’excellence de la relève technologique » Mme Lorraine Bédard, présidente, Novalait inc.

M. Pierre Prémont, Président directeur général, Fonds québécois de la recherche sur la nature et les technologies (FQRNT)

15 h 45 – Remise des bourses d’excellence 2008 / Programme de bourses d’études de la Commission canadienne du lait en collaboration avec Novalait inc.

Mme Lorraine Bédard, présidente, Novalait inc. M. Gilles Froment, directeur principal, Politiques et affaires corporatives, Commission canadienne du lait

16 h 00 – Allocution de clôture Mme Lorraine Bédard, présidente, Novalait inc. 16 h 15 – Vin et Fromage

“Carrefour de la relève technologique” Semaine en science et technologie laitières de la FIL

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Novalait Technological Forum 2008

Poster session at the “Carrefour de la relève technologique” 1. Monitoring milk starter activity using a molecular technique – Fabien DACHET,

Université Laval 2. Milk microbiota dynamics as revealed by molecular techniques – Éric RASOLOFO,

Université Laval 3. Impact of milk Trans fats on cholesterol metabolism – Geneviève GRENIER, Université Laval 4. Impact of milk Trans fats on plasmatic lipoproteins – Annie MOTARD-BÉLANGER,

Université Laval 5. Factors influencing variation of milk components in Québec – Marie-Claude FERLAND,

McGill University 6. Culture media to study the effect of fatty acids on probiotic growth – Delphine SÈNE,

Université Laval 7. Impact of a brief dry period on Quebec dairy herds – Débora SANTSCHI, Agriculture and

Agri-Food Canada, FRDC 8. Brief dry period and mammary gland development – Philippe BERNIER DODIER,

Agriculture and Agri-Food Canada, DRSDC 9. Brief dry period and feed efficiency – Maude JOLICOEUR, Agriculture and Agri-Food

Canada, DRSDC 10. Characterization of membranes from fat globule fragments – Jessika BÉDARD-ST-AMAMT,

Université Laval 11. Effect of heat treatment of cream on cheese processing aptitudes of buttermilk –

Sophie IZMIROGLU, Université Laval 12. Starch – exopolysaccharids interactions of lactic bacteria from yogurt –

Marie-Claude GENTÈS, Université Laval 13. Sugar concentration in cheeses – Chantale MORIN, Université Laval 14. Antibacterial activity of whey protein hydrolysates – Émilie TURGEON, Université Laval 15. Detection of lactic bacteria phages in the air – Daniel VERREEAULT, Université Laval 16. Cheddar cheese bacteria: abundance or activity? – Émilie DESFOSSÉS-FOUCAULT,

Université Laval 17. On the Camembert trail: leading edge techniques to uncover its metagenome –

Marianne ARTEAU, Université Laval

18. Survey on cheddar cheese quality: the microbial community under interrogation! – Sadjia RACHEK, Université Laval

19. Subclinical mastitis: prevent or treat infections? – Simon DUFOUR, Université de Montréal, Faculté de Médecine Vétérinaire

20. Virulence factors of S. aureus associated with chronic mastitis in Canada – Bich VAN LE THANH, Université de Montréal, Faculté de Médecine Vétérinaire

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IDF DAIRY SCIENCE AND TECHNOLOGY WEEK

MAY 12 – 16, 2008, QUEBEC, CANADA

SESSION 1 – Tuesday, May 13, 2008

Health Properties of Milk and Dairy Products 8:45 a.m.

INVITED SPEAKER Trans Fatty Acids and Cardiovascular Disease: An Update on Naturally

Occurring Trans Fat? Dr. Benoît LAMARCHE

STELA Dairy Research Center / Institute of Nutraceuticals and Functional Foods

(INAF), Université Laval, Québec, CANADA

Trans fatty acids (TFA) in foods have recently attracted worldwide attention, owing to their undesirable effects on human health. In Canada, it has been estimated that TFA intake in 1995 averaged 8.4 g/day, which was equivalent to approximately 3.7% of the total energy intake in adults. When combined altogether, data from epidemiological studies indicated that an increase in TFA intake equivalent to 2% of daily energy was associated with a significant 25% greater risk over time. These data also indicated that on a gram to gram basis, TFA had a 10 times greater impact on the risk of CVD than SAT fat, suggesting that the impact of TFA on the cardiovascular health goes far beyond its effect on cholesterol levels. Although small in relative terms, the proportion of total dietary TFA coming from “natural” sources (mostly ruminant milk and meat) is not trivial. In fact, this proportion can be as high as 90% in countries where TFA from industrial sources have been eliminated. While the intake of TFA from industrially hydrogenated vegetable oils (iTFA) is now well known to have a deleterious impact on cardiovascular health, the effects of TFA from ruminants (rTFA) are virtually unknown. This presentation will summarize the results of two recent clinical studies that have compared the impact on dietary iTFA and rTFA on cardiovascular risk factors. In women, iTFA lowered HDL cholesterol, LDL cholesterol, and triacylglycerol concentrations compared on a gram to gram basis with rTFA. On the other hand, dietary rTFA seem to have the same effects on plasma LDL cholesterol levels as iTFA in men. However, our own studies indicate that at a dietary intake achievable in “real life”, rTFA are very unlikely to have any effect on most cardiovascular risk factors. These data, along with earlier evidence from epidemiological studies suggest that TFA from ruminants sources are unlikely to be harmful from a heart health perspective. Benoît Lamarche is professor at the Department of food science and nutrition at Laval University. He also is chair of the Canada Research Chair in Nutrition, Functional Foods and Cardiovascular Health since 2001. Dr. Lamarche completed a bachelor’s degree in Biochemistry (1991). He carried on graduate studies in Physiology at Laval University (1996) and postdoctorate training at the Faculty of medecine of the University of Toronto (1998). His research concentrates mainly on nutrition, functional foods and their impact on cardiovascular health.

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SESSION 1 – Tuesday, May 13, 2008 (cont’d)


Antiviral Activity of Esterified Whey Proteins Jean-Marc CHOBERT1, Mahmoud SITOHY1, 2, Sylviane BILLAUDEL3, Michèle

DALGALARRONDO1, and Thomas HAERTLE1*

1UR Biopolymères interactions assemblages, INRA, Nantes, Équipe fonctions et interactions des protéines laitières, Nantes, 2Université de Zagazig, Faculté d’Agriculture, Département de

biochimie, EGYPTE, 3Université de Nantes, UFR des sciences pharmaceutiques, bactériologie-virologie, Nantes, FRANCE

Esterification is a simple and cheap reaction without production of harmful secondary products. Depending on its extent, it produces proteins/peptides positively charged with a polycationic character, able to interact with polyanionic substances. Interactions between esterified milk whey proteins (beta-lactoglobulin, alpha-lactalbumin) transformed in polycations and (i) polyanionic molecules of DNA or (2) virus directed against Lactocoques used in dairy industry have been demonstrated previously. Recently, we have shown that such modified whey proteins can inhibit the replication of several viruses such as Herpes simplex virus, cytomegalovirus, poliovirus type-1, or Coxsackie virus B6. The antiviral activity of esterified whey proteins (IC50 = 20-40 µg mL-1) observed against virus infecting Vero cells depended on five factors (in order of importance): concentration of esterified proteins, multiplicity of infection, duration of incubation, timing of esterified proteins addition after infection, and extent of esterification of proteins. The relative amounts of viral RNA were less affected by the esterified proteins concentration than was the virus infectious titer, indicating that inhibitory proteins may slow down viral multiplication, yielding reduced amounts of viral RNA. Hence, we can propose a new product enhancing surface sterilisation in food and bio-technologic industries susceptible to viral infections. Such a product could be incorporated in detergents used in the surface treatment in industry, hospitals, household and for cutaneous treatment. It could be used also as one of the elements of defence of agro-production and human means against deliberate infections (agro-terrorism, bio-terrorism) and against accidental infections.

10:00 a.m.

Health Promoting Properties of Fermented Buttermilk. Brian A. MURRAY* and Philip M. KELLY

Moorepark Food Research Centre, Teagasc, Moorepark, Fermoy, Co. Cork, IRELAND

The milk fat globule membrane (MFGM) is increasingly recognised to possess important biologically active protein and phospholipid components. MFGM biologically active lipids include structural components of membranes and lipoproteins and function as signalling molecules in processes such as regulating cell growth and cross membrane trafficking. Certain sphingolipids are known to influence apoptotic pathways, and their anti-cancer effects may lead to potential constituents in an anti-cancer regime. In addition, studies on intestinal digestion of milk have identified a sphingomyelinase activity which degrades sphingomyelin into sphingosine and ceramide both of which are potent anticancer agents. Considerable progress is being made in recent years with regard to the measurement and characterisation of MFGM components in buttermilk and other dairy product sources. However, little work has been done in relation to the role of fermentation on the composition and biological activity of MFGM. Fermentation is applied in the course of dairy product manufacture while bacterial growth and metabolism also takes place in vivo following ingestion. Hence, a study has been initiated which aims to examine changes that occur during fermentation of buttermilk containing MFGM by selected lactic acid bacteria. The objective, therefore is to examine whether the various forms of fermentation have a beneficial effect in enhancing the biological activity of MFGM-based components and extracts.

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Randomized Controlled Trial Comparing the Bioavailability of Vitamin D3 from Fortified Cheddar Cheese, Fortified Low-Fat Cheese, and Supplement

Dennis WAGNER*, Gloria SIDHOM, Susan J. WHITING, Dérick ROUSSEAU, and Reinhold VIETH

Department of Nutritional Sciences, University of Toronto, Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, CANADA

There is a need to increase the options for vitamin D fortification. We have developed a method to fortify hard cheeses with vitamin D3. We compared the bioavailability of vitamin D3 from fortified hard cheeses and from a well-characterized liquid vitamin D3 supplement. Sixty adults were randomly given weekly servings of fortified full-fat Cheddar cheese (34 g), fortified low-fat cheese (41 g), or vitamin D3 supplement. These contained 28,000 IU vitamin D3, equivalent to 4,000 IU/d. 20 adults were also randomized to placebo. Bioavailability of vitamin D3 was assessed by comparing the serum 25-hydroxyvitamin D [25(OH)D] response over 8 weeks. In the placebo group, initial serum 25(OH)D, 55.0 ± 25.3 nmol/L (mean ± SD), declined over the 8-week winter protocol, to 50.7 ± 24.2 nmol/L (paired t test, p=0.046). In the vitamin D3-treated groups, the mean increases in serum 25(OH)D from baseline to 8 wk were: 65.3 ± 24.1 nmol/L (Cheddar cheese), 69.4 ± 21.7 (low-fat cheese), 59.3 ± 23.3 (supplement with food), and 59.3 ± 19.6 nmol/L (supplement without food); these changes were significantly different from the placebo group (ANOVA, p<0.0001) but not from one another (ANOVA, p=0.62). Compared with baseline, serum parathyroid hormone decreased significantly with both the fortification (paired t test, p=0.003) and the supplementation (paired t test, p=0.012) strategies. Vitamin D3 is equally bioavailable from fortified hard cheeses and from supplement. Therefore, hard cheese is a viable food for vitamin D fortification, and can help to enhance vitamin D.

11:30 a.m.

Caseinphosphopeptides and Calcium Absorption from Bovine and Caprine Calcium-Fortified Fermented Milks

Adela MORA-GUTIERREZ1*, Miguel MORA-GUTIERREZ 2, and Changzheng WANG3 1Cooperative Agricultural Research Center, Prairie View A&M University, TX, 2Department of

Gastroenterology, Universidad Central de Venezuela, Caracas, VENEZUELA, and 3Human Nutrition Research, Kentucky State University, Kentucky, USA

In an effort to improve calcium (Ca) status, some investigators have focused on finding food ingredients that might enhance calcium absorption and/or utilization. Caseinphosphopeptides (CPP) are released from the proteolytic digestion of casein during food processing or gastrointestinal digestion. CPP prevent the formation of insoluble Ca salts thereby increasing the bioavailability of Ca in the ileum or the distal small intestine. Four major casein components are present in casein of bovine milk: αs1-, αs2-, β-, and κ-casein. However, in caprine milk there is a high degree of variance in casein proportions among animals, which appears to be genetically controlled. The ability of CPP prepared by enzymatic hydrolysis from the respective caseins (extrinsic CPP) to enhance Ca absorption from bovine and caprine Ca-fortified fermented milks was compared with intrinsic CPP released from the gastrointestinal digestion of caseins to enhance Ca absorption. Growing male Sprague Dawley rats were randomly assigned (7/group) to receive bovine and caprine Ca-fortified fermented milks alone or enriched with CPP (1 mg/ml). An aqueous solution of the bovine and caprine Ca-fortified fermented milks (10% w/v) labeled extrinsically with 45Ca was given by gastric intubation. Absorption was determinated from measurements of radioisotope activity in femur. Addition of CPP enhanced Ca absorption from Ca-fortified fermented milk. Ca absorption was less pronounced in Ca-fortified fermented milk without added CPP. Based on the results of this study we can conclude that the addition of CPP have beneficial effect on the absorption of CaCO3 added to bovine and caprine fermented milks.

12 NOON – LUNCH - POSTER SESSION: Rooms Crémazie – Garneau, and Hall

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SESSION 2 – Tuesday, May 13, 2008


1:30 p.m.

INVITED SPEAKER Dairy Components and Products for Weight Management

and Metabolic Syndrome Riina KEKKONEN

Valio Ltd, R&D and University of Helsinki, Institute of Biomedicine, FINLAND Metabolic syndrome is a cluster of metabolic disorders which are risk factors for cardiovascular disease and type-2 diabetes. These risk factors include obesity,

hypertension, dyslipidemia and impaired glucose tolerance. Abdominal obesity and insulin resistance are thought to represent common underlying factors of the metabolic syndrome, which features also a chronic low-grade inflammatory state. Genetic factors have an influence on the development of metabolic syndrome, but lifestyle and health behaviour have a great impact on the progress as well as the development of metabolic syndrome. The key recommendations for the prevention and management of metabolic syndrome include promotion of healthy lifestyle through weight loss, change in dietary composition, and increase in physical activity. There is emerging evidence that dairy products could have protective effects against obesity and metabolic syndrome. In epidemiological studies, high dairy calcium intake is associated with lower weight. High calcium intake from milk products seems both to prevent weight gain and to improve the results of dieting. A strong reverse correlation has been observed between regular and high consumption of milk products and the development of metabolic syndrome and type-2 diabetes in adults. The underlying mechanism of action is still unclear but it is most probably related to milk proteins. Also other components may contribute to the beneficial effects. Whey protein has been investigated for its satiety increasing and insulinotropic properties. Dairy protein and calcium has been linked to improved body composition. In addition, peptides, calcium and other minerals may have blood pressure lowering effects. Recently, intestinal microbes have been linked with obesity which may have potential therapeutic implications through modulation of the gut microbiota with fermented or probiotic products. In recent years a number of products designed to help in weight management have been launched. Increasingly, these are positioned as making the consumer feel fuller for longer and therefore cutting down on hunger between meals and helping to avoid snacking. This satiety trend features new products with combinations of fibre and protein, fibre on its own or different branded ingredients. Indeed, the food industry possesses a central role in the solution of the obesity and metabolic syndrome problem. It is obviously not solved entirely by the action of the food industry, but the whole society has to be involved. And still, the individuals themselves make the final choices. Successful life style changes in terms of diet require sensible daily choices of foods and drinks, which can be supported by the expertise of the food industry. Riina Kekkonen works as a research scientist at Valio Research Centre, Finland since 2001. She is responsible for planning, conducting and coordinating experimental and clinical studies. Her main research concern the effect of probiotics on immune response, health effects of dairy proteins and weight management. She obtained her Master’s degree (Health Sciences, Nutrition) at Kuopio University. Besides her work at Valio Research Centre, she is at the moment finalizing her PhD studies at the University of Helsinki, Faculty of Medicine, Institute of Biomedicine, on the topic “Immunomodulatory effects of probiotics” (cellular and clinical studies).

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2:15 p.m.

Effects of Caseins on the Thermal Stability of β-Lactoglobulin Yie Hui YONG* and Allen E. FOEGEDING

Department of Food, Bioprocessing, and Nutrition Sciences,

North Carolina State University, USA Casein fractions have been shown to act as molecular chaperons and inhibit aggregation of whey proteins in dilute solutions (<1% w/v). The goal of this investigation was to determine if this approach is a viable way to stabilize higher concentrations of proteins as desired for beverage application. Mixtures of β-lactoglobulin (6% w/v) and either β-casein (0.01 to 2% w/v) or α-casein (2% w/v) were adjusted to pH 6.0 and heated (70 to 90°C) for 20 min, cooled then analyzed to determine the aggregation degree. Overall aggregation was determined by solution turbidity (optical density at 400 or 600 nm). Soluble aggregate mass and radius of gyration were determined by multi-angle laser light scattering (MALLS). Addition of 0.05% (w/v) β-casein or greater caused a drop in turbidity. In contrast, inhibition was not observed when 2% (w/v) α-casein was added. Moreover, prolonged heating (60 min) of β-lactoglobulin with 2% (w/v) β-casein (pH 6.0) at 90°C produced a clear solution while β-lactoglobulin solutions containing α-casein formed semi-turbid gels after heated for 15 min. MALLS measurements confirmed the turbidity results. For instance, at 75°C, solutions containing 2% (w/v) β-casein and 6% (w/v) β-lactoglobulin produced aggregates with lower molar mass (80% in the range of 3.0x106 to 2.0x107 g/mol) and smaller radius of gyration (80% in the range of 19 to 30 nm) as compared to their control cohorts (3.5x107 to 7.0x108 g/mol and 58 to 85 nm, respectively). These results show that β-casein is a feasible component to stabilize higher concentration whey proteins in beverages.

2:45 p.m.

Gelation of Undenatured Milk proteins by Interaction with Anionic Polysaccharides and its Potential Applications

Sandra I. LANEUVILLE1* and Sylvie L. TURGEON1

1STELA Dairy Research Center, Institute of Nutraceuticals and Functional Foods (INAF), Université Laval, Québec, CANADA

The gelation of three different milk proteins, β-lactoglobulin, BSA and sodium caseinate was achieved by electrostatic interaction with different anionic polysaccharides (xanthan gum, λ-carrageenan). The uniqueness of this work resides in that no thermal, enzymatic or any other denaturing treatment was applied to the protein or the mixture at any time. Gelation was induced by in-situ acidification to a pH where both molecules carry net opposite charges, resulting in a tridimensional network stabilized by the electrostatic attractive interactions between both molecules. Our studies showed that this gel could be formed in a wide range of protein to polysaccharide ratios, ionic strengths, and concentrations (including extremely low concentrations ~ 0.03-3 wt%), depending on the studied macromolecules. The kinetics of gel formation was followed by dynamic rheology, microscopy and in some cases, by static light scattering. It was found that the gels were composed of aggregated complexes of a fractal nature (fractal degree ranging from ~ 2.1-2.4). Moreover, our results demonstrate the great impact that the molecular charge density and conformation had on the gel strength and its internal structure, with globular and more charged proteins forming stronger and denser gels than random coil proteins. Interestingly, some gels were more stable at higher ionic strengths, due to charge shielding, which diminished the strong electrostatic interaction, thus preventing syneresis. Potential applications are being studied, e.g., in milk systems, where understanding the molecular factors leading to this type of interaction is essential to fully grasp the role of bacterial exopolysaccharides in the structuration of products such as yoghurt. Other studies include the use of this gel as a vehicle for liposomes that could eventually be used to protect/transport delicate molecules such as enzymes, nutraceuticals or drugs.

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3:45 p.m. Relation Between Physical State and Survival of Freeze-Dried Probiotic Bacteria.

Lone KURTMANN*, Charlotte U. CARLSEN, Leif H. SKIBSTED, and Jens RISBO

Food Chemistry, Department of Food Science, Faculty of Life Science, University of Copenhagen,

Frederiksberg, DENMARK The composition of freeze-drying medium for probiotics is important in relation to stability and survival of the bacteria during storage. The drying process removes water, and the matrix components, mainly carbohydrates, serve to embed and protect the bacteria in the dry state. During dehydration under suitable conditions, high concentrations of carbohydrates will form an amorphous glassy matrix, which is characterised by an extremely high viscosity. In a glassy matrix the molecular mobility is lowered due the high viscosity, and consequently the rates of detrimental reactions in a bacteria culture should be limited. Dried bacteria are suggested to be protected during storage if the they are stored below the glass transition temperature, Tg, and in the current study we have constructed two water activity-temperature state diagrams, one for each of two different matrices embedding the probiotic bacteria Lactobacillus acidophilus. The state diagrams map the changes in the physical state of the freeze-dried bacteria cultures in relation to storage temperature and water activity, and based on this information it was possible to investigate directly the relation between the physical state of the dried cultures and the bacteria survival during storage. The results show that careful selection of temperature and water activity for storage of dried probiotics is important, but also that detrimental reactions cannot be fully eliminated by storage in glassy states.

4:15 p.m. Does Milk Processing Influence Casein Digestibility in Infant?

Didier. DUPONT1*, A. Mackie2, D. Molle1, J. Leonil1, and E.N.C. Mills2

1INRA – UMR Science et technologie du lait et de l’oeuf, Rennes, FRANCE 2Institute of Food Research (IFR), Colney, Norwich UNITED KINGDOM

Bovine milk proteins are the first non-human proteins consumed by the infant, after or instead of breast-feeding. Among them, caseins are the major ones and due to their flexible structures are known to be extremely sensitive to digestion, leading to the formation of peptides that may have positive (anti-hypertensive, immunomodulatory, opioid) as well as negative (allergenic) effects on infant health. Processing may have a significant impact on casein structure. For instance, heat-treatment is known to enhance protein–protein interactions generating supramolecular structures like aggregates. The objective of this work was to determine if processing could make caseins more resistant to digestion using a physiologically relevant in vitro model mimicking the infant gut and to determine the protein region that showed resistance to digestion. Sixteen well-defined and differing casein-containing matrices (purified caseins, micelles, raw, pasteurized and sterilized milks, yogurts…) were submitted to in vitro digestion using an infant gut model. Digested samples were analysed by SDS-PAGE, RP-HPLC and indirect ELISA using polyclonal antibodies. Four digested samples (raw, pasteurized, sterilized milks and yogurt) were further characterized using 25 different monoclonal casein-specific antibodies and LC-MS-MS. Large fragments were found resistant to digestion and corresponded to the areas β-CN(f76-93), κ-CN(f98-169), αs2-CN(f36-75) and αs1-CN(f149-199) to a lesser extent. These sequences corresponded to hydrophobic areas of the caseins at pH 3.0, i.e. the pH used during the gastric phase. Comparison of the short peptides patterns showed that processing of raw milk into sterilized and yogurt led to a higher resistance of casein to in vitro digestion. 4:45 p.m.: POSTER SESSION: Rooms Crémazie – Garneau, and Hall

15



SESSION 3 – Wednesday, May 14, 2008

Microbial Quality of Milk and New Tools 8:30 a.m.

INVITED SPEAKER

Probiotics vs Gastrointestinal Infection Dr. Mansel GRIFFITHS

Department of Food Science and Canadian Research Institute for Food Safety, University of Guelph, Ontario, CANADA

Many dairy products containing pre- or probiotics are appearing on the market that purport to be good for you. However, the scientific basis for these health claims has been limited. It is only in recent years that the mechanism of action of

probiotics has been investigated and many of their beneficial health effects substantiated. For example, many studies have shown that probiotics protect against gastrointestinal infection and it has been thought that this is mediated by competition between probiotic microflora and pathogens for intestinal colonization sites and stimulation of the host’s immune system. We have recently shown that probiotics also produce bioactive molecules that down-regulate virulence genes in enteric pathogens and this effect may be mediated through interference of cell-cell signalling pathways. These molecules have the potential to be used as prophylactics to prevent foodborne infections and will provide the industry with opportunities to develop “designer foods” targeting certain sectors of the population most at risk of foodborne infections. Dr. Mansel Griffiths is senior chairholder since 1991 of the DFO/NSERC Senior Industrial Research Chair in Dairy Microbiology. His research team is engaged in research to develop detection methods for foodborne microorganisms and to learn more about how microorganisms behave in food and food production/ processing environments. They are leaders in the application of bioluminescence for the study and detection of foodborne microorganisms which allows to study organisms in vivo without recourse to culture. They have developed diagnostic methods for the detection of foodborne pathogens that can be applied directly in foods. They also have developed novel methods for using bacteriophage to detect foodborne pathogens which are being commercialized. There is substantial interest in the development of phage as antimicrobial agents for use in human and veterinary medicine. They also have the potential for controlling contamination at food processing facilities.

16

SESSION 3 – Wednesday, May 14, 2008 (cont’d)


Screening of the Proteolytic Psychotrophic Flora in Raw Milk: Does the Role of Pseudomonas Fluorescens Need Revision?

Sophie MARCHAND*, Kim HEYLEN, Katleen COUDIJZER, Paul DE VOS, Koen DEWETTINCK, Jan DE BLOCK, and Marc HEYNDRICKX

Institute for Agriculture and Fisheries Research Technology & Food, Melle, BELGIUM

Proteolytic psychrotrophs, particularly Pseudomonas, are the key microorganisms responsible for spoilage of milk and dairy products, due to their ability to produce heat-resistant proteases. To investigate the psychrotrophic heat-resistant proteolytic activity in raw milk, 86 raw milk samples were screened. 103 proteolytic strains isolated and identified to species level using API 20NE. 91.3% of the isolates belonged to Pseudomonas. Consistent with literature data, 50% of the isolates were identified as P. fluorescens according to API 20NE. Although API tests are frequently used for rapid identification of microorganisms, they have limited taxonomic resolution for certain Pseudomonas species groups. As DNA-based techniques have provided more reliable approaches to bacterial identification and differentiation at the species level, a (GTG)5-PCR was performed as screening method. The fingerprints displayed a large genetic diversity in the isolated strains on species and infraspecific level. Nevertheless, these data revealed two major clusters representing isolates with great milk spoilage potential. For a polyphasic identification approach, 29 representatives were subjected to Fatty Acid Methyl Ester, 16S rDNA and rpoB sequence analysis. The first two techniques appeared not discriminatory enough to identify Pseudomonas isolates to species level. On the other hand, rpoB analysis identified the main spoilers in our milk screening study as Pseudomonas fragi and Pseudomonas lundensis. These results were confirmed by DNA-DNA hybridisation. Moreover, Pseudomonas fluorescens appeared to play a minor role in the investigated samples. Misidentification in the past due to biochemical testing systems and the absence of a polyphasic approach could probably partly explain why Pseudomonas fluorescens appears to be such a heterogeneous species and why its role in milk spoilage has probably been overestimated.

9.45 a.m.

Differences in Heat Resistance and Growth Limits of Listeria monocytogenes Strains, and Identification of Potential Biomarkers

Stijn VAN DER VEEN1,2*, Roy MOEZELAAR2, Jeroen WOUTERS1, Tjakko ABEE2, and Marjon H. J. WELLS-BENNICK1,2

1NIZO Food Research, Division Health & Safety, Ede, The Netherlands, 2Top Institute Food and Nutrition (TIFN), Wageningen, THE NETHERLANDS

Listeria monocytogenes is a foodborne pathogenic bacterium which is the causative agent of listeriosis. Due to the severity of the disease and the fact that its incidence is increasing in numerous european countries, L. monocytogenes is of great public health concern. Food manufacturers, including those producing dairy products containing unpasteurized milk or ready-to-eat foods, have had to re-evaluate their processes in order to maintain safe food products. One of the most important strategies to reduce the incidence of food-borne listeriosis is to prevent growth to high numbers in the case of contamination. We assessed the growth limits and heat resistances of a large number of L. monocytogenes strains (total 138) of different origins of isolation and serotypes. Significant differences in heat resistance was observed between strains. Furthermore, growth was evaluated using combinations of low pH, sodium lactate, and high salt concentrations in BHI broth at different temperatures. We found that serotype 4b strains, which are most commonly isolated in cases of clinical listeriosis, have the highest acid and salt tolerance at 30 °C. The highest tolerance for high NaCl concentrations was found for serotype 1/2b strains at 7 ºC, at neutral pH and pH 5.5. The association of certain L. monocytogenes serotypes with particular stress responses likely reflects adaptation to specific niches, possibly explaining the abundance of certain types in foods and others in clinical cases. We were furthermore able to identify specific genes associated with particular phenotypes, which may be candidate genes to be used as suitable biomarkers for specific L. monocytogenes strains in foods.

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SESSION 3 – Wednesday, May 14, 2008 (cont’d)


A Toolbox to Quantify Enterotoxin Gene Expression in a Complex Microbial Ecosystem

Manon DUQUENNE1,2*, Marina AIGLE1, Isabelle BATAILLON1, Pascal QUENEE1, Tiphaine LEROY, Elise BOREZEE-DURANT1, Sylviane DERZELLE2,

Véronique DEPERROIS-LAFARGE2, Marielle BOUIX3, and Agnès DELACROIX-BUCHET1*

1INRA, Unité bactéries lactiques et pathogènes opportunistes, Jouy-en-Josas, 2Agence française de sécurité sanitaire des aliments, Laboratoire d’études et de recherches sur la qualité des aliments et

des procédés agro-alimentaires, 3AgroParisTech Massy, Massy, FRANCE

Cheese is a complex and dynamic microbial ecosystem characterized by the presence of a large variety of bacteria, yeasts and moulds. Some microorganisms, including species of lactobacilli or lactococci, are known to contribute to the organic quality of cheeses, whereas the presence of others may lead to spoilage or constitute a health risk. Staphylococcus aureus is recognized worldwide as an important foodborne pathogen, owing to the production of enterotoxins in food matrices. In order to study enterotoxin gene expression during cheese manufacture, we developed an efficient method to recover total RNA from cheese and a robust method to study gene expression by quantitative RT-PCR. RNA is isolated from cheese in two steps: A cheese sample is first homogenized in citrated water with a mechanical blender and cells are isolated by centrifugation. Cells are then disrupted and total RNA is purified using a classical protocol. This method yields pure preparations of undegraded RNA accessible for RT-PCR. It is important that quantitative RT-PCR data be normalized with a proper internal control to obtain reliable results with biological significance. We thus investigated the expression stability of ten housekeeping genes potentially useful as references in studies of S. aureus grown in milk or cheese, using the geNorm Visual Basic Application for Microsoft Excel. Enterotoxin gene expression can therefore be normalized using the geometric mean of the three most stably expressed reference genes. And gene expression is correlated with enterotoxin quantity.

11:15 a.m.

Development of Antibody Microarray-based Biosensor for Bacterial Detection

Isabelle NOISEUX1*, Jean-Pierre BOUCHARD1, Fabien CLAVEAU1, François BABIN1, François ROY-MOISAN1, Marci VERNON1, and Shu CHEN2

1Institut National d’Optique (INO), Québec, 2Laboratory Services Division,

University of Guelph, Ontario, CANADA The detection, identification and quantification of different pathogenic microorganisms simultaneously at low cost are of great interest to the agrifood industry. This paper describes the development of a low cost biosensor based on antibody microarrays. The biosensor is a LED-based microarray reader that uses imaging processing algorithms to improve the signal-to-noise ratio over that of commercial readers. Proof-of-concept tests were carried out with Salmonella and demonstrated detection of 105 CFU in less than 2 hours with no interference by the presence of other bacteria in the sample. Results from an overnight enriched-sample showed the detection of 10 CFU of Salmonella in 25g of a Salmonella-inoculated food sample. These results are compared to those obtained with a commercial microarray reader and show equal to better performance. The developed biosensor is a low cost solution for simultaneous detection of different types of bacteria or other organisms of concern in complex food samples.

11:45 LUNCH - POSTER SESSION: Rooms Crémazie – Garneau, and Hall

18



SESSION 4 - Wednesday May 14, 2008 p.m. (cont’d)


1:30 p.m.

Non-Thermal Processing Technologies and Dairy Product Quality

Dr. Geoffrey W. SMITHERS*§,

Cornelius (Kees) VERSTEEG, and Jay SELLAHEWA

Food Science Australia, New South Wales, AUSTRALIA

In the 21st century, innovation and product differentiation in the dairy industry will be essential in enhancing international competitiveness in a truly global

food marketplace. Such innovation and differentiation will also be critical in meeting consumer demands for so-called ‘miracle foods’ that are not only safe and nutritious, but also natural, promote health and well-being, great tasting, convenient, economical to manufacture, environmentally-friendly, and individually tailored for each consumer. These marketplace drivers create quite a challenge to the dairy industry who must ‘think outside the traditional box’, often to new and novel approaches that when adapted and applied in dairy systems will result in innovation, differentiation, and consumer excitement and acceptability. Several non-thermal processing technologies, notably ultra-high pressure, power ultrasonics, and pulsed electric field, are creating an impact in agri-food processing around the world. While these technologies have been largely viewed as alternative non-thermal techniques to enhance microbiological safety and quality of food streams and products, they are increasingly being developed for a range of other applications in dairy systems, including (a) improved processing effectiveness and enhancement of quality; (b) differentiation of ingredients and products including tailored functionality, both physical, nutritional and organoleptic; (c) preservation of unstable bioactive ingredients; (d) modulation of enzyme activity; and (e) hypoallergenic ingredients and products. In this presentation, the potential of the major non-thermal processing technologies in dairy systems will be introduced, together with an examination of their current and potential applications in processing and modulating dairy streams and products. The presentation will explore the science underpinning the observed effects, and how this understanding can accelerate and strengthen commercialization of these non-thermal dairy processes, and capture benefit for the dairy industry.

Dr. Geoffrey Smithers is the Director of Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO). He is responsible for setting the strategic framework for relationship and business development in international markets, and directing and coordinating activities in these markets. Dr. Smithers has a background in both fundamental and applied R&D in the areas of advanced processing and ingredient functionality, together with 'hands-on' experience in food business practice. He published plentifully in scientific literature and invented several patented applications.

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2:15 p.m. High Pressure Homogenization as Alternative to Thermal Treatment to Improve the Microbial

Safety, Shelf-Life and Functionality of Milk and Milk Products Maurice NDAGIJIMANA, Francesca PATIGNANI*, Lucia VANNINI, Pamela VERNOCCHI,

Rosalba LANCIOTTI, and M. E. GUERZONI

Alma Mater Studiorum, University of Bologna, Department of Food Science Bologna, ITALY

Novel non-thermal processes represent an alternative to thermal treatment to improve quality, safety and functionality of milk and milk-based products. Among the alternatives proposed, the “high-pressure homogenization” (HPH) is one of the most promising technologies and its potential has been applied to the dairy field both for the milk decontamination and product diversification. The aim of this research, included in the european project “Innovative non-thermal processing technologies to improve the quality and safety of ready-to-eat meals (HighQ RTE)”, was to evaluate the potential of HPH to inactivate pathogenic species such as Listeria monocytogenes and Salmonella enteritidis in raw milk and to promote the proliferation and viability of probiotic bacteria inoculated in HPH processed milk. The data obtained were compared with those obtained using traditional heat treatment. The results regarding the milk decontamination showed that the inactivation curves of S. enteritidis were linear up to the 4th cycle at 100 MPa, after which their slopes diminished. Also L. monocytogenes resulted to be sensitive to HPH. A reduction of 5 Log cfu/ml was obtained with 8 pressure pushes at 100 MPa. The use of HPH applied to milk increased the performance of the probiotic cultures co-inoculated and extended the product shelf-life during the refrigerated storage. The data obtained confirmed the industrial importance of this technology both for milk decontamination and optimization of probiotic fermented milks. In addition, the effect of HPH on the organoleptic quality of milk and milk products was evaluated in relation to sulfur and aroma compounds detected respectively by GC-FPD and GC-MS/SPME.

2:45 p.m. Electrodialysis With Ultrafiltration Membrane:

A New Way for Peptide Fractionation Laurent BAZINET1*, Jean-François POULIN1, and Jean AMIOT2

1STELA Dairy Research Center, Institute of Nutraceuticals and Functional Foods (INAF),

2Department of Food Science and Nutrition, Université Laval, Québec, CANADA β-lactoglobulin tryptic hydrolysates contain numerous bioactive peptides and amongst others, β-lg 142-148, which has been reported to be an anti-hypertensive sequence. However, to obtain an ingredient with higher functionality, this peptide has to be isolated. Electrodialysis with ultrafiltration membrane (EDUF), a technique developed recently, has demonstrated very high selectivity for the separation of acid or basic bioactive peptides. EDUF couples size exclusion capabilities of UF membranes (membrane cut-off) with the charge selectivity (driving force = electric field) of electrodialysis. The main goal of this work was to increase cationic peptide migration to the permeate solution and more specifically to concentrate the β-lg 142-148 sequence by studying the influence of three main process parameters (effective membrane surface, strength of the electrical field and feed solution flow rate). The increase of the membrane area resulted in a 4 fold increase of the peptide concentration. Moreover, raising the electrical field strength also resulted in increasing considerably the peptide concentration in the permeate solution. In the best conditions, a total migration of 29% was obtained for peptide β-lg 142-148 after only 90 minutes of processing with a relative concentration of 30%. However, at high electrical field and membrane area, the final migration rate was affected due to a retro-migration phenomenon linked with pH changes. It appeared that the feed solution flow rate had no impact on the yield of the process but induced changes in the selectivity.

20



3:45 p.m. Microfiltration and Thermal Treatment for Extending the Shelf-Life of Milk:

Factors Affecting Product Quality and Stability Veronika KAUFMANN*1, Verena SCHMIDT², Siegfried SCHERER², and Ulrich KULOZIK1

1,²Technische Universität München, GERMANY 1Chair for Food Process Engineering and Dairy Technology, ²Chair for Microbial Ecology

According to the concept of minimal processing, extended shelf-life (ESL) milk is produced by using microfiltration (MF) in combination with a mild thermal process in a hybrid mode. Until now the contributions for each of these processing units to operating profit were neither understood nor quantified. Furthermore this technology is applied without sufficient knowledge about the effects of processing conditions (e.g. filtration parameters) and up- or downstream factors (raw milk quality, storage conditions) on product attributes and alteration. Particularly, it is not known how far these different factors are affecting microbial survival and growth, residual enzyme activity as well as sensory characteristics and, hence, quality and absolute shelf-life of the milk. But towards process design and product optimization, a fundamental investigation of these interrelations is required and therefore is the aim of this study. MF was demonstrated to remove a major part of the initial bacterial bulk load (decimal reduction about 3.5) and thus to deliver a significant contribution to achieving a prolonged milk shelf-life. The hybrid processing neither led to serious objectionable (chemical or organoleptic) product alteration, but nor to a complete inactivation of all potentially shelf-life limiting microbes (like Bacillus species) or bacterial (proteolytic and lipolytic) enzymes. It could be shown that the shelf-life capacity of ESL milk (12 to 24 days) therefore is related to microbial as well as enzymatical quality of the raw product and also depends on storage temperature, but much less on processing parameters.

4:15 p.m. Proteolysis and Lipolysis of Ultra-High Pressure Homogenized Treated Milk

During Refrigerated Storage Julieta PEREDA*, Victoria FERRAGUT, Martín BUFFA, Buenaventura GUAMIS,

and Antonio TRUJILLO*

Centre Especial de Recerca Planta de Tecnologia dels Aliments (CERPTA), Departament de Ciència Animal i dels Aliments, Facultat de Veterinària, Universitat Autònoma de Barcelona, SPAIN

Ultra high-pressure homogenization (UHPH) is a new technology that is being studied as an alternative to pasteurization. This technology is able to obtain milk with microbial and physico-chemical characteristics similar to that of high-pasteurized milk. However, the effect of UHPH on proteolysis and lipolysis has not been studied until now. Therefore, the aim of this work was evaluating proteolytic and lipolytic changes in UHPH milks during refrigerated storage and comparing with the effects of heat (PA; 90 ºC, 15s). Proteolysis of milk subjected to UHPH (200-300 MPa, Ti=30/40 ºC) and PA treatments and the relation of plasmin residual activity on it was studied by capillary electrophoresis, HPLC peptide, pH-4.6-soluble nitrogen and free amino acids. Inactivation of plasmin increased as UHPH pressure did and extensive proteolytic degradation was observed in 200 MPa 40 ºC milk. Hydrolysis of β-casein, hydrophobic peptide and pH-4.6-SN levels increased with the higher residual plasmin, meanwhile hydrophilic peptides were not affected. Although, UHPH-treated samples exhibited higher casein hydrolysis compared to PA milk and there were no significant differences in peptide and pH-4.6-SN content between 300 MPa and PA samples. Immediately after treatments, there were no significant differences between samples in free fatty acid (FFA) levels. During storage, an increase of FFA was observed in samples treated at 200 MPa, however, only 200 MPa 30 ºC milk showed levels of FFA significantly higher than those of the other UHPH and PA samples. This study shows how UHPH treatments influence milk properties, suggesting that treatment at 300 MPa could be used as an alternative to pasteurization.

4:45 p.m.: CLOSING ADDRESS, Dr. Paul Paquin, Chairman of the Organizaing Committee

5:00 p.m. POSTER SESSION: Rooms Crémazie – Garneau, and Hall

6:30 p.m. : CLOSING DINNER at The Capitole de Québec

21



Poster presentations

Tuesday and Wednesday, May 13 - 14, 2008

Reference Number

Title/Authors

1

Electroreduction of milk and effect on storage in glass jars

Laurent BAZINET*, Jérome PERICOU, and Monica ARAYA-FARIAS

STELA Dairy Research Center, Institute of Nutraceuticals and Functional Foods (INAF), Laval University, Quebec CANADA

[email protected]

2

Biodiversity of coagulase-negative staphylococci in French milk, cheeses products and environment

Marie-Hélène DESMONTS1, Emmanuel COTON2, Monika COTON2, Emmanuel JAMET3, Sabine LEROY4, Sylvie LORTAL*5, and Régine TALON4

1Aerial CRT et ITAI, 2ADRIA Normandie, 3ITFF, 4INRA Clermont, 5INRA Rennes, FRANCE

[email protected]

3

Design and validation of a diagnostic microarray for microbial risk assessment in coagulase negative staphylococci isolated from fermented dairy products

Sergine EVEN1, Sabine LEROY2, Cathy CHARLIER1, Nouri BEN ZAKOUR1,3, Jean-Paul CHACORNAC2, Isabelle LEBERT2, Emmanuel JAMET4, Marie-Hélène DESMONTS5, Emmanuel COTON6,

Sylvie LORTAL*1, Régine TALON2, and Yves LE LOIR1

1UMR1253 STLO INRA Rennes, FRANCE, 2UR454 Microbiologie, INRA Clermont Theix, FRANCE, 3LBEP, University of Edinburgh, UK, 4ITFF, La Roche sur Foron, FRANCE, 5AERIAL, Illkirch, FRANCE, 6ADRIA

Normandie, Villers Bocage, FRANCE

[email protected]

4

Effect of dissolved gases and heat treatments on oxidative degradation of a dairy beverage enriched with polyunsaturated fatty acids

Hélène GIROUX*, Geneviève ACTEAU, Hassan SABIK, and Michel BRITTEN

Food Research and Development Centre, Agriculture and Agri-Food Canada, Quebec, CANADA

[email protected]

5

Impact of ripening on probiotic-delivering capacity of semi-hard cheese: in vitro assessment using gastro-intestinal dynamic (TIM-1) model

Ehab KHEADR, Nassra DABOUR, Geneviève PETIT, and Jean-Christophe VUILLEMARD*

STELA Dairy Research Center, Institute of Nutraceuticals Functional Foods (INAF), Laval University, Quebec CANADA

[email protected]

22



Poster presentations (cont’d)

6

Reserveratrol-β-lactoglobulin interaction studied by circular dichroism and fluorescence

Li LIANG* and Muriel SUBIRADE

STELA Dairy Research Center. Institute of Nutraceuticals and Functional Foods (INAF), Laval University, Quebec CANADA

[email protected]

7

Lactoferrin separation by electrodialysis with ultrafiltration membrane (EDUF) Ndiaye NAFISSATOU*1, YVES POULIOT1,,Linda SAUCIER1,2,

Lucie BEAULIEU3, and Laurent BAZINET1

1STELA Dairy Research Center, Institute of Nutraceuticals and Functional Foods (INAF), Laval University, Quebec, 2Départment of animal sciences, Laval University, Quebec, 3Department of

biology, chemistry and geography, Université du Quebec in Rimouski, CANADA

[email protected]

8

Study of a soluble complex of β-lactoglobulin and fucoidan, a bioactive polysaccharide from brown seaweed

Laurie-Eve RIOUX* and Sylvie L. TURGEON

STELA Dairy Research Center, Institute of Nutraceuticals and Functional Foods (INAF), Laval University, Quebec CANADA

[email protected]

9

Lactococcus lactis affects several staphylococcus aureus virulence gene expression during mixed cultures

Sergine EVEN1, Cathy CHARLIER1, Marina CRETENET1, Sylvie LORTAL*1, Pascal LOUBIERE2, Muriel COCAIGN-BOUSQUET2, Sébastien NOUAILLE2, and Yves LE LOIR1

1UMR1253 STLO-INRA Rennes, FRANCE, 2LISBP, UMR CNRS 4, UMR INRA 792, INSA, Toulouse, FRANCE

[email protected]

10

Effect of milk fermentation on global gene expression in human blood cells

Mary Francina SAGAYA1,2, Guy VERGÈRES1, Michel BELLIS3, Hans-Peter BACHMAN*1, and Richard F. HURRELL2

1Agroscope Liebefeld-Posieux (ALP), Bern, SWITZERLAND 2Laboratory for Human Nutrition, Institute of Food Science and Nutrition, Swiss Federal Institute of Technology Zurich (ETHZ), Zurich,

SWITZERLAND, 3Centre de Recherche de Biochimie macromoléculaire (CRBM), Montpellier, FRANCE

[email protected]

11

Production and quality of cheddar cheese made from microfiltered or CO2 acidified milk stored during 9 days

Sophie TURCOT*1, Daniel ST-GELAIS1, Gaétan BÉLANGER1, Denis ROY2, and Gisèle LAPOINTE2

1Food Research and Development Centre, Agriculture and Agri-Food Canada, Quebec, CANADA, 2STELA Dairy Research Center, Institute of Nutraceuticals and Functional Foods (INAF),

Laval University, Quebec CANADA

[email protected]

23




12

Study of interactions between exopolysaccharides produced by strain lactobacillus rhamnosus RW-9595M and milk proteins

Véronica PLESCA* and Sylvie TURGEON

STELA Dairy Research Center, Institute of Nutraceuticals Foods (INAF), Laval University, Quebec CANADA

[email protected]

13

Stabilization of whey protein isolate-pectin complexes against pH adjustment to 7.0 and their use in yoghurts

Marie-Claude GENTES*1, Sylvie TURGEON1, and Daniel ST-GELAIS2

1STELA Dairy Research Center. Institute of Nutraceuticals and Functional Foods (INAF), Laval University, Quebec CANADA, 2Food Research and Development Centre, Agriculture and Agri-Food

Canada, Quebec, CANADA

[email protected]

14

Oxidative stability of lipids in electro-reduced milk

Sanaz HARATIFAR*1, Laurent BAZINET1, Michel BRITTEN2, and Paul ANGERS1

1Dairy Research Center (STELA) and Institute of Nutraceuticals Foods (INAF), Laval University, Quebec, 2Food Research and Development Centre, Agriculture and Agri-Food Canada, Quebec,

CANADA

[email protected]

15

Large-scale isolation of caprine and bovine β-casein.

Sophie, LAMOTHE*, Gilles ROBITAILLE, Daniel ST-GELAIS, and Michel BRITTEN

Food Research and Development Centre, Agriculture and Agri-Food Canada, Saint-Hyacinthe, Quebec, CANADA

[email protected]

16

Calcium limits gut absorption of long chain fatty acids during ingestion of dairy matrixes

Christelle LOPEZ1, Frédéric GAUCHERON*1, Valérie BRIARD-BION1, Denis LAIRON2, and Jacques MOUROT3

1UMR Science et Technologie du Lait et de l’France (STLO) INRA-Agrocampus, Rennes, France, 2UMR Nutrition Humaine et Lipides INSERM 476 – INRA 1260, Faculté de Médecine de la Timone, Marseille,

France, 3UMR Systèmes d’Elevage, Nutrition Animale et Humaine (SENAH) INRA-Agrocampus, Saint-Gilles, FRANCE

[email protected]

24




17

The comparative study of monolaurin treatments , and monolaurin with EDTA treatments to control Escherichia coli post-processing contamination on Laur

(Laurec), a traditional Iranian whey cheese, stored at 4 ºC in sterile packages

Jaafarpour JAVAD1, Feiz allah beigi HOSSEIN1, Ehsani ALI2, and Razavi ROHANI Seyed MEHDI2

1Faculty of veterinary medecine, Urmia University, 2Department of food hygiene, Faculty of veterinary medecine, Urmia University’ IRAN

[email protected]

18

Rheology of microgel particles made of whey protein isolate/κappa-carrageenan: effect of shear on the microparticle size

Samy GAALOUL*1, Sylvie L. TURGEON1, and Milena CORREDIG2

1STELA Dairy Research Center, Institute of Nutraceuticals and Functional Foods, Laval, University, Quebec, CANADA, 2Department of Food Science, University of Guelph, Guelph, Ontario, CANADA

[email protected]

19

Analysis by real-time PCR of expression of the beta-galactosidase genes of Bifidobacterium longum strains in the presence of various sugars during the exponential phase of growth

Zahira CHOUCHANE*, Ismaïl FLISS, and Denis ROY

STELA Dairy Research Center, Institute of Nutraceuticals and Functional Foods (INAF), Laval University, Quebec, CANADA

[email protected]

20

Formation of structure during rennet-induced gelation of milk containing high methoxyl pectin

Alexandra ACERO LOPEZ*, Milena CORREDIG, and Marcela ALEXANDER

Department of Food Science, University of Guelph, Guelph, Ontario, CANADA

[email protected]

21

Study of Escerichia coli infections in mammary glands of buffalo and the antibacterial drug resistance of the isolates in Urmia Iran

Malahat AHMADI

Urmia University, Faculty of veterinary medicine Department of Microbiology, Urmia, IRAN

[email protected]

25




22

Effect of concentration by ultrafiltration on the rennet-induced gelation of caseins studied in situ by diffusing wave spectroscopy

Christina COOPER*, Marcela ALEXANDER, and Milena CORREDIG


[email protected]

23

Microencapsulation of probiotics by means of enzymatically induced cross linking of dairy proteins

Thomas HEIDEBACH* and Ulrich KULOZIK

Technische Universität München, Chair for Food Process Engineering and Dairy Technology, Freising, GERMANY

[email protected]

24

Kinetics of the lactosylation of β-lactoglobulin in a dry system

Marianne KAABER THOMSEN*, Karsten OLSEN, Jeanette OTTE, and Leif H. SKIBSTED

Department of Food Science, Faculty of Life Science, University of Copenhagen, Rolighedsvej Frederiksberg, DENMARK

[email protected]

25

Modeling of probiotic stability, post acidification and precipitation of a probiotic lactic beverage produced by different combinations of milk base, starter culture, incubation

temperature, dilution and salt percentage during cold storage

Parinaz TAHERI1*, Mohammad REZA EHSANI2, Kianoosh KHOSRAVI DARANI3, and Seyed HADI RAZAVI2

1Azad University, Research and Science Branch, Tehran, IRAN, 2Department of Food Science and Technology, Faculty of Agriculture, Tehran University, IRAN, 3Department of Food Technology

Research, National Nutrition of Food Technology Institute, Shahid Beheshti University of Medical Science, Tehran, IRAN

[email protected]

26

Effects of pasteurization and ageing time on structural parameters of whipped dairy emulsions enrichment by unsaturated fatty acids

Ali BAZMI1* and Perla RELKIN2

1Food Science and Technology Group, Faculty of Agriculture, University of Tabriz, Tabriz, IRAN, 2Laboratoire de Biophysique des Matériaux Alimentaires,

École Nationale Supérieure des Industries Alimentaires, Massy, FRANCE

[email protected]

26




27

Raw milk dispensers in Italy

Roberta LODI, Franco SANGIORGI*, Milena BRASCA, and Stefano ZANDALINI

National Research Council-Institute of Sciences of Food Production (CNR-ISPA), Istituto di Ingegneria Agraria dell’Università degli Studi di Milano; Milano ITALY

[email protected]

28

Farm sale of raw milk: old flavours and nutraceutic properties

Milena BRASCA, Roberta LODI*, Tiziana SILVETTI, and Laura VANONI

National Research Council-Institute of Sciences of Food Production (CNR-ISPA) Milano ITALY

[email protected]

29

Effect of experimental staphylococcus aureus mastitis on composition of goat milk

Nancy MUNGATANA

University of Egerton, KENYA

[email protected]

30

Human blood neutrophils primed by a bovine whey protein extract increase their specialized functions of innate defense

Daniel RUSU1*, Réjean DROUIN2, Sylvie GAUTHIER3, Yves POULIOT3, and Patrice E. POUBELLE1

1Centre de recherche en rhumatologie et immunologie (CRCHUL), 2Advitech inc., Québec, 3STELA Dairy Research Center, Institute of Nutraceuticals and Functional Foods (INAF), Université Laval,

CANADA

[email protected]

31

Structure formation during acidification of milk: Study based on scanning electron microscopy (SEM)

Ivo PISKA* and Douglas G. DALGLEISH


[email protected]

32

Correlation between non-enzymatic browning reactions and the loss of vitality of probiotic bacteria in freeze-dried dairy cultures

Charlotte U. CARLSEN*, Lone KURTMANN, and Leif H. SKIBSTED

Food Chemistry, Department of Food Science, Faculty of Life Science, University of Copenhagen, Frederiksberg, DENMARK

[email protected]

27



_____________________________________________________________________


33

Viability of bifidobacteria strains in yogurt and simulated gastrointestinal transit

Terri D. BOYLSTON*, Karen S. KERR, and Aubrey F. MENDONCA

Iowa State University, Dept. Food Science & Human Nutrition, Ames, Iowa, USA

[email protected]

34

Dynamic in vitro gastrointestinal digestion (TIM-1) of a growth factors-enriched whey product: hydrolysis profile and effect

on intracellular glutathione of digested fractions

Samira NABIL*1, Sylvie F. GAUTHIER1, Réjean DROUIN2, and Patrice POUBELLE3

1STELA Dairy research Center, Institute of nutraceuticals and Functional Foods (INAF), Laval University, Quebec, CANADA 2Advitech inc., Quebec, CANADA,

3Research center in rhumatology and immunology (CRCHUL), Quebec, CANADA

[email protected]

35

Production of galacto-oligosaccharides and hetero-oligosaccharides with disrupted bacterial cells

Vivian LEE*, Clarissa SCHWAB, and Michael GÄNZLE

Department of Agricultural, Food, and Nutritional Sciences, University of Alberta, CANADA

[email protected]

36

Potentialities of high pressure homogenization for the production of bio-yoghurts

Francesca PATRIGNANI1, Rosalba LANCIOTTI1, Maurice NDAGIJIMANA1, Wilhelm H. HOLZAPFEL2, and M. E. GUERZONI1.

1Alma Mater Studiorum - University of Bologna, Department of Food Science, Bologna, ITALY, 2Institute of Hygiene and Toxicology, Federal Research Centre for Nutrition, GERMANY

[email protected]

37

Bio-K+ International: Clinical research; efficacy and safety of Bio-K+ CL1285®

Marcia T. RUIZ*1, François MARTIN2, and Serge CARRIERE2

1Bio-K+ International, Montreal, Quebec, CANADA, 2Université de Montréal, CANADA

[email protected]

38

Sodium caseinate affects the aggregation of rennet-altered casein micelles

Zafir GAYGADZHIEV*, Marcela ALEXANDER, Arthur HILL, and Milena CORREDIG


[email protected]

28




39

Séparation of TGF-β2 from a whey protein isolate by crossflow microfiltration in the presence of a ligand

Wassef BEN OUNIS*1, Sylvie F. GAUTHIER1, Sylvie L. TURGEON1, Olivier MORONI2, and Yves POULIOT1

1STELA Dairy research Center, Institute of nutraceuticals and Functional Foods (INAF), Laval University, Quebec, CANADA, 2Advitech inc., Quebec, CANADA

[email protected]

40

Effect of processing on triacylglycerol composition in milk fractions

Samia MEZOUARI*1, Michel BRITTEN2, Paul ANGERS1, and Yves POULIOT1

1STELA Dairy research Center, Institute of nutraceuticals and Functional Foods (INAF), Laval University, Quebec, CANADA, 2Food Research and Development Center, Agriculture and Agri-Food

Canada, Quebec, CANADA

[email protected]

41

Serum cholesterol level in mice: effects of probiotics and milk lipid extracts

Cuibai FAN*, Anne-Marie DAVILA, Michel DUBARRY, Agnes BAGLIERI-MARSSET, and Daniel TOME

UMR914 Nutrition Physiology and Ingestive Behavior, INRA, AgroParisTech, CRNH- Paris, FRANCE

[email protected]

42

Effect of pasteurization on the interactions between casein micelles and milk fat globule membranes in cream and buttermilk

Sophie IZMIROGLU*1, Michel BRITTEN2, Laurent BAZINET1, and Yves POULIOT1

1STELA Dairy research Center, Institute of nutraceuticals and Functional Foods (INAF), Laval University, Quebec, CANADA, 2Food Research and Development Centre, Agriculture and Agri-Food

Canada, St-Hyacinthe, Quebec, CANADA

[email protected]

43

Protein composition changes in bovine milk fat globule membrane isolated from buttermilk caused by industrial pasteurization

Jessika BÉDARD-ST-AMANT*1, Yves POULIOT1, Sylvie GAUTHIER1, Dominique MICHAUD2, and Michel BRITTEN3

1STELA Dairy research Center, Institute of nutraceuticals and Functional Foods (INAF), Laval University, Quebec, CANADA, 2Department of Phytology and Institute of Nutraceuticals and Functional

Foods (INAF), Laval University, Quebec, CANADA, 3Food Research and Development Centre, Agriculture and Agri-Food Canada, Saint-Hyacinthe, Quebec, CANADA

[email protected]

29




44

Antibacterial activity of peptide fractions isolated from a tryptic hydrolysate of whey proteins

Émilie TURGEON*, Sylvie GAUTHIER, Ismail FLISS, and Julie JEAN

STELA Dairy research Center, Institute of nutraceuticals and Functional Foods (INAF), Laval University, Quebec, CANADA

[email protected]

45

Fractionation of β-lactoglobulin peptide mixture by means of nanofiltration in the presence of ligands

Bertrand P. CHAY PAK TING, Sylvie F. GAUTHIER, and Yves POULIOT


[email protected]

46

A new technological approach for the bovine colostrum fractionation

David P. LACHKAR*1, Éric LAMIOT2, Sylvie L. TURGEON1, Sylvie F. GAUTHIER1, and Yves POULIOT1

1STELA Dairy research Center, Institute of nutraceuticals and Functional Foods (INAF), Laval University, Québec, CANADA, 2Advitech Inc., Quebec, CANADA

[email protected]

47

Digestion of conjugated linoleic acids (CLA) from different sources in a dynamic in vitro gastrointestinal model

Rachel. GERVAIS*1, Edward R. FARNWORTH1,2, Ismaïl FLISS1, Ehab E. KHEADR1, M.R. VAN CALSTEREN2, Claude CHAMPAGNE1,2, and P.Yvan CHOUINARD1

1STELA Dairy research Center, Institute of nutraceuticals and Functional Foods (INAF), Laval University, Quebec, CANADA, 2Agriculture and Agri-food Canada, St-Hyacinthe, Quebec, CANADA

[email protected]

48

Emulsifiers for granulated ghee

Ravindra KUMAR1 and Niels Erik LARSEN2

1Danisco (India) Pvt. Ltd, Gurgaon, INDIA, 2Danisco A/S, Edwin Rahrs, Brabrand, DENMARK

[email protected]

49

Characterization of acid-induced gels of mixtures of β-lactoglobulin and α-lactalbumin

Ladan RABIEY*, and Michel BRITTEN

Agriculture and Agri-Food Canada, Saint-Hyacinthe, Quebec, CANADA

[email protected]

30




50

Evaluation of the impact of microfiltration, acidification with carbon dioxide and prolongation of the storage period of milk on the diversity and dynamics

of the bacterial community during ripening of Cheddar cheese

Sadjia RACHEK*1, Daniel ST-GELAIS2, Gisèle LAPOINTE1, Steve LABRIE1, and Denis ROY1

1STELA Dairy research Center, Institute of nutraceuticals and Functional Foods (INAF), Laval University, Quebec, CANADA, 2Agriculture and Agri-Food Canada, St-Hyacinthe, Quebec, CANADA

[email protected]

51

Transcriptome profiling of Lactococcus lactis subsp. cremoris under conditions simulating Cheddar cheese manufacture.

Amel TAÏBI*1, Nassra DABOUR1, Maryse LAMOUREUX2, Denis ROY1, and Gisèle LAPOINTE1

1STELA Dairy research Center, Institute of nutraceuticals and Functional Foods (INAF), Laval University, Quebec, CANADA, 2Agropur, inc., Granby, Quebec, CANADA

[email protected]

52

Impact of digestive stresses on tolerance and metabolic activity of bacteriocin-producing lactic acid bacteria and bifidobacteria

Jedidi HAJER*, Ehab E. KHEADR, and Ismail FLISS


[email protected]

53

Combined effects of bacteriocins and gastrointestinal stress conditions on the inhibition of listeria mononcytogenes

Helen ENGEL1, Christophe LACROIX1, Annina ZIHLER1, Ehab KHEADR2, and Ismaïl Fliss*2

1Institute of Food Science and Nutrition, Swiss Federal Institute of Technology, Zentrum, CH-8092 Zürich, SWITZERLAND, 2STELA Dairy research Center, Institute of nutraceuticals and Functional

Foods (INAF), Laval University, Quebec, CANADA

[email protected]

54

Impact of Lactobacillus acidophilus NCFM cell surface proteins on its binding to milk fat globule membrane in buttermilk

Guillaume BRISSON* and Rafael JIMENEZ-FLORES;

Dairy Product Technology Center, California Polytechnic State University, San Luis Obispo, CA 93407, USA

[email protected]

31




55

A new central source for bacteriocins characterization

Riadh HAMMAMI1, Abdelmajid ZOUHIR1, Jeannette BEN HAMIDA1, and Ismail FLISS2§

1Unité de Protéomie Fonctionnelle & Biopréservation Alimentaire, Institut Supérieur des Sciences Biologiques Appliquées de Tunis, Université El Manar, Tunisie, 2STELA Dairy Research Center, Institute

of Nutraceuticals and Functional Foods (INAF), Laval University, Quebec, CANADA

§[email protected]

Use of scientific database maker for the characterization of protein sequences and design of specialized biological databases

Riadh HAMMAMI 1, Abdelmajid Zouhir1, Jeannette Ben Hamida1 and Ismail Fliss2§

1Unité de Protéomie Fonctionnelle & Biopréservation Alimentaire, Institut Supérieur des Sciences Biologiques Appliquées de Tunis, Université El Manar, TUNISIE, 2STELA Dairy Research Center,

Institute of Nutraceuticals and Functional Foods (INAF), Laval University, Quebec, CANADA

§[email protected]

mardi 20 mai 2008

32

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