Past, current and potential utilisation of active and intelligent packaging

systems for meat and muscle-based products: a review

Joe P. Kerry

Department of Food and Nutritional Sciences,National University of Ireland,

Cork, Ireland

52nd ICoMST, Dublin, Ireland

Meat Packaging

“The efficient containment, preservation and protection of a meat product and all necessary information required during packing, transport, storage, sale and use, along with the

provision of convenience, taking into consideration all legal and environmental issues”

Importance of Meat Packaging at Retail Level

Customer choice of a muscle-based product is dependent upon many factorsAppearance most important

Important meat/pack quality attributesMeat ColourShelf-life StabilityDrip/Moisture LossSensory AttributesOdour Gain/LossPack IntegrityPack AppearanceLabelling (dates, additives, product support information)Convenience

Packaging functions (First level packaging)

Technical Function Prevents/Allows: Free movement of gases Entry or exit of moistureProduct illumination Prevent contamination

Sales Function Provides:InformationConvenience

Commercial Meat Packaging Formats

Boxed

Overwrap

VacuumCommon processHeat-shrinkThermoforming vacuum processSkin vacuum packaging

Modified Atmospheres (MAP)Retail and bulk gas flushing

Problems Associated with Meat Packaging(First level packaging)

Exposure to oxygen:Systems generally not hermeticMeat products exposed to varying levels of oxygen

Moisture loss:Fresh muscle foods lose moisture in the form of drip-lossDrip-loss in packs can reduce product shelf-life

Compartmentalised odour/flavour: Development occurs principally through the production of volatile gaseous compounds via product-package-gas interactions

Introduction to Active PackagingIntroduction to Active Packaging(Second level packaging)(Second level packaging)

Active packaging:

Incorporation of certain additives into packaging systems with the aim of maintaining or extending product quality and shelf-life

or

Active when it performs some desired role in food preservation other than providing an inert barrier to external conditions (Hutton, 2003)

or

Active when the packaging elements change the condition of the packed food to extend shelf-life or improve safety or sensory properties, while maintaining quality of packaged food (Ahvenainen, 2003)

Active packaging applications:

Absorbing/scavenging oxygen, carbon dioxide, moisture, ethylene, flavours, taints, UV light

Releasing/emitting ethanol, carbon dioxide, antioxidants,preservatives, sulphur dioxide, flavours, pesticides

Removing catalysing food component removal: lactose, cholesterol

Temperature control insulating materials, self-heating and self-cooling packaging,microwave susceptors and modifiers, temperature-sensitive packaging

Microbial control UV and surface-treated packaging materials

Moisture Control

Dri-Loc® Absorbent pads, CRYOVAC®, Sealed Air Corporation

- Moisture absorbent pads and trays with applications for meat and poultry- Lowering of water activity to suppress microbial growth- Systems consist of super-absorbent polymers located between two other plastic layers

Commercial Examples:

Fresh-R-Pax™ Absorbent pads, Fresh-R-Pax™ Absorbent trays, Maxwell Chase Technologies, LLC.

• Pads perforated with tiny one-way valves • Juices absorbed from the bottom • Prevents meat from drying

Moisture Control

Advantages:

Enhanced product appearance and freshness

– shelf life extension

Removes and retains spoilage bacteria

Reduces costly rewraps and product downgrades

Reduces product and packaging waste

Pads protect product display cases

– enhanced visual appeal to customers

Oxygen Scavengers

Elevated O2 levels in food packages may facilitate:

Microbial growth

Off-odour and off-flavour development

Colour changes

Nutritional losses

A significant reduction in product shelf-life

Existing technology based on: iron powder oxidation, ascorbic acid oxidation, photosensitive dye oxidation, enzymatic oxidation (e.g. glucose oxidase), unsaturated fatty acids, rice extract or immobilised yeast on a solid substrate

Traditional MAP or vacuum packaging may not facilitate complete removal of O2=> Residual O2 may be removed using oxygen scavenging technology

Majority of commerically available O2 scavengers based on the principle of iron oxidation:

Fe → Fe2+ + 2e-

½ O2 + H2O + 2e- → 2OH-

Fe2+ + 2OH- → Fe(OH)2

Fe(OH)2 + ¼ O2 + ½ H2O → Fe(OH)3

Available as labels, sachets, cards or films (incorporation of scavenging agent into the packaging film)

Mitsubishi Gas Chemical Co.

Ageless® Sachet

Ageless® Label

Effective with a variety of packaging materials

Reduce and maintains O2 to < 0.01%

De-oxygenation time ~ 1 to 4 days

Oxygen Scavengers

Emco Packaging Systems.

Atco® Sachet

Atco® Labels

Multisorb Technologies Inc. FreshPax® Sachets FreshPax® Labels

Advantages:- Significantly reduces oxygen levels in packs - Reduces oxidation reactions (pigments, lipids)- Reduces aerobic microbial growth

Disadvantages:- Concerns regarding anaerobic pathogens- Activation - moisture dependent- Sachet leakage/consumption

Applications in sliced cooked meats (e.g. hams)

Prevent discoloration in fresh beef (Allen et al., 1996; Tewari et al., 2001)

Oxygen Scavengers

Oxygen Scavengers

Reduce headspace O2 from 1% to ppm levels in 4-10 days ~ comparable with O2scavenging sachets

Applications:Dried or smoked meat products, processed and sliced meats

UV light activated films composed of an O2 scavenger layer extruded into a multilayer film

Commercial examples:Cryovac® OS2000™ polymer based oxygen scavenging filmZERO2TM developed by CSIRO and VisyPak Food Packaging

Carbon Dioxide Emitters and Scavengers

CO2 emitting sachets or labels can also be used alone

Further research required - safety risks of CO2 in packaging systemse.g. C. botulinum type B

Removal of O2 or dissolution of CO2 in the product creates a partial vacuum which may cause collapse of flexible packaging

⇒ Dual action CO2 generators / O2 scavengers

Function of CO2 to inhibit microbial growth and extend product shelf-life

Commercial examples:

Ageless® GMitsubishi Gas Chemical Co.

FreshPax® MMultisorb Technologies Inc.

Based on either ferrous carbonate or a mixture of ascorbic acid and sodium bicarbonate

Verifrais™ package (SARL Codimer) extends shelf-life of fresh red meatsStandard tray with a false, perforated bottom containing sachet of sodium bicarbonate/ascorbateJuice dripping from the meat onto the sachet results in CO2 emission

⇒ Replacement of CO2 absorbed by the meat⇒ Prevention of package collapse

CO2 absorbers (sachets) consisting of either calcium hydroxide and sodium hydroxide or potassium hydroxide, calcium oxide and silica gel

⇒ Removal of CO2 during storage to prevent bursting of package⇒ Applications in dehydrated poultry products and beef jerkey

Carbon Dioxide Emitters and Scavengers

Antimicrobial Packaging

Antimicrobial agents: acid anhydride, alcohol, bacteriocins, chelators, enzymes, organic acids and polysaccharides

Antimicrobial agents - may be coated, incorporated, immobilised or surface-modified onto package materials

Antimicrobial films classified into two types:

⇒ films containing an antimicrobial agent which migrates to the food surface

⇒ films effective without migration

Antimicrobial coatings

Incorporation of antimicrobial agents

Nisin coated films – reduction of S. typhimurium on surface of fresh broiler skin and drumsticks (Natrajan and Sheldon, 2000)Alginate coatings containing organic acids reduced levels of L. monocytogenes, S.typhimurium and E. coli 0157:H7 on beef carcasses (Siragusa and Dickson, 1993)

Films containing acetic or propionic acid in a chitosan matrix with/without lauricacid or cinnamaldehyde applied to bologna, cooked ham or pastrami (Ouattara et al., 2000)Grapefruit seed extract incorporated into multilayer polyethylene films reduced aerobic and coliform bacteria in minced beef (Ha et al., 2001)

Antimicrobial Packaging

Immobilisation

Pack inserts

Nisin-adsorbed bioactive inserts reduced L. innocua and S. aureus in hams (Scannell et al., 2000)

Sachets of oregano essential oil in combination with MAP extended the shelf-life of fresh beef (Skandamis and Nychas, 2002)

AgION™ (concentrate)AgION Technologies LLC

Nisaplin® (extract)Integrated Ingredients

Microgard™ (film)Rhone-Poulenc

Commercial examples:

Few commercial successes – Ag-substituted zeolite incorporated into plastics in Japan

Antimicrobial Packaging

Zeomic™ (powder)Sinanen Zeomic

Introduction to Intelligent Packaging (Second Level Packaging)

Packaging systems which monitor the condition of packaged foods to give information about the quality of the packaged food during transport and storage (Ahvenainen, 2003)

Intelligent packaging in some way senses properties of the food it encloses or the environment in which it is kept and which is able to inform the manufacturer, retailer and consumer of the state of these properties

Information extensive, though much of it is conceptual

Limited commercial application to date

Tamper evidence/pack integrity - breach of pack containment

Safety/quality indicators- time-temperature indicators (TTIs) - gas sensing devices - microbial growth- pathogen detection

Traceability/anti-theft devices- radio frequency identification (RFID) labels/tags/chips

Product authenticity- holographic images, logos - hidden design print elements- RFID

Intelligent Packaging Applications

IndicatorsSubstances that indicate the presence, absence, or concentration of another substance or the degree of reaction between two or more substances by means of a characteristic change, especially with respect to colour

Visual O2 indicators: use in low O2 packsNumber of patents (redox dyes) – MAP mince steaks, mince pizzas

DisadvantagesHigh sensitivity to residual O2 in MAPReversibility - undesirable where O2 is consumedduring bacterial growth

Few commercial devices availableAgeless-Eye®, Vitalon®, Samso-Checker®

Integrity (leak) indicators

Provide direct product quality information resulting from microbial growth or chemical changes within a meat product

Potential indicator metabolitesOrganic acids, ethanol, biogenic amines, CO2, H2S, microbes

DisadvantagesBased in broad-spectrum colour changesTarget metabolites do not necessarily indicate poor quality

Toxin Alert – ToxinguardTM

Freshness indicator measures Pseudomonas sp.

Antibodies in polyethylene-based packaging- can also detect pathogens

Freshness Indicators

Time-Temperature Indicators (TTIs)

Small tag or label used to show time-temperature history to whicha perishable product has been exposed

Diffusion-based, enzymatic and polymer-based TTIs offer most potential

VITSAB®, Fresh-Check® and 3M Monitor® - effective indicators of meat quality

TTIs: Price estimates from €0.02 to €0.15

CheckPoint® (Vitsab International, Sweden)

‘Do not use if circle is pink’

Radio Frequency Identification Tags (RFID)

Tags affixed to assets (cattle, pallets, meat bins, packs) to transmit information to a reader

Tags - transponder and antenna with unique number or identifier- non-contact, non-line-of-sight, can penetrate bio-matter including meat (~ 125 kHz)

Wireless data collection technology that uses electronic tags for storing data and identification of people, animals or objects.

Tags • passive: simple, cheap, short-range, powered by energy from reader• active: battery powered, more info (temp, RH, nutritional info, cooking instructions etc), longer range

Costs• ~ €0.40 and €0.75 per tag (passive) ; ‘€0.07 in volumes of 106’• to cost ~ €0.01 after 2007?• decrease in cost critical to implementation

Applications to meat• trial stage• tracking of beef from Namibia to UK• birth to beef: RFID/bar code tracking• ‘iBoS’ transport crate for meat products• Wal-Mart, Tesco, Target, Metro AG

RFID on boxes of frozen meat (TrolleyponderTM)

Radio Frequency Identification Tags (RFID)

Sensors

Devices used to detect, locate or quantify energy or matter, giving a signal forthe detection of a physical or chemical property to which the device responds

Most contain two functional units:Receptor - physical or chemical information transformed into a form of energyTransducer - device that transforms this energy into a useful analytical signal

R&D mainly in biomedical and environmental applications

Used to determine a primary measurable or a secondary physical, chemical or biological variable – ‘the marker concept’

High development costs, exacting industry specifications and safety considerations have limited commercial realisation although significant steps have been made

Need for traceability, guaranteed quality and safety is promoting development

Gas Sensors

Recent developments in optical oxygen sensors based on fluorescence quenching

Non-invasive technique for gas analysis through translucent materialsFluorescent or phosphorescent dye encapsulated in a polymer matrix=> O2 penetrates dye-polymer coating and quenches luminescence (energy transferred to O2) => quantified against pre-determined calibration

Ruthenium, palladium(II)-, platinum-porphyrin and porphyrin-ketone complexes show promise for intelligent packaging use Relatively long emission lifetimes (~40-500 μs) best for food packaging applications

Fabrication – dissolution of indicator dye and polymer support in organic solvent followed by drying

Large scale, continuous production possible

Operating criteria for optical O2 sensors in intelligent packaging:

Working range: 0 to 100 kPa O2; detection limits 0.01- 0.1 kPa.

Temperature dependence: Effective from -20 to +70 °C

Response: < 10-3 s, ideal for rapid on-line screening

Stability: Effective time/temperature/light/migration stability

Toxicity: Single pack sensor ~ 1 mg, of which > 95% support matrix: non-hazardous

OxySense® - first commercially available fluorescence quenching sensor

• > 98% correlation with GC• Stable to 150 °C without loss of sensitivity• Rapid (< 5 s per measurement)• Headspace and liquid measurements

Gas Sensors

Oxygen Sensors

Migration of active components of O2 sensors in food packaging applicationsO’Riordan et al. (2005)

Effects of residual oxygen in anaerobic MAP chicken and beefSmiddy et al. (2002a,b,c)

Use of O2 sensors printed directly onto packaged sous vide beef lasagneO’Mahony et al. (2004)

Use of O2 sensors for headspace analysis of commercial ham productsPapkovsky et al. (2002)

Platinum-based O2 sensors as quality control instruments for meat productsFitzgerald et al. (2001)

Current research - new sensing materials and detection systems

Vacuum packed beef with O2 sensing membrane

O2 sensing equipment

Bio-Sensors

Compact analytical devices that detect, record and transmit information pertaining to biological reactions

• Bioreceptor specific to a target analyte (enzymes, antigens, microbes, hormones etc.)

• Transducer to convert biological signals to an electrical response (electrochemical, optical etc.)

Contaminating bacteria render bar-code unreadable

SIRA Technologies Inc. Food Sentinel SystemTM

Few commercially available systems but more widespread use predicted

Active and Intelligent Packaging – The Future

These packaging technologies anticipated to grow significantly over the next 10 years,due principally to:

- Consumer demands for meat and other food products which are premium quality and whichprovide adequate shelf-life, safety, convenience and information

- Reduction in packaging material costs as formats grow in popularity/sales volume, and as newer and cheaper formats emerge through research and development

- Greater demands by retailing outlets for extended product shelf-life

- Concerns regarding product authenticity and bio-terrorism

- Growing efforts to reduce unnecessary product/package wastes

AcknowledgementsAcknowledgements

My sincerest thanks to:My sincerest thanks to:

Dr Sean Hogan Dr Sean Hogan &&

Dr Michael ODr Michael O’’GradyGrady

for their invaluable assistance and support for their invaluable assistance and support throughout this entire projectthroughout this entire project

Thanks for yourThanks for yourattentionattention