Meat Processing 1 Common preservation techniques Prods 1...1 Meat Processing 1 Common preservation...
Transcript of Meat Processing 1 Common preservation techniques Prods 1...1 Meat Processing 1 Common preservation...
Meat Processing 1Common preservation techniques
A webinar presented by:
Dr Andy Bowles
Attendee Notes
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Meat Processing 1Common preservation techniques
Dr Andy Bowles
Introduction
In this webinar I will discuss: General principles of preservation Common techniques used in the meat industry Heat treatment Lowering of water activity (aw) Reduction of pH Use of chemical preservatives Use of modified atmospheres
Types of meat product
MeatPreparations
Burgers
Sausages
Kebab
Cured Meatpieces
Cured rawmeat
Curedcooked meat
Raw-cookedmeat
Frankfurters
Meat loaf
Pre-cookedcooked
products
Blackpudding
Liversausage
Fermentedsausages
Salami
Driedproducts
Biltong
Jerky
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General principles
Chemical Composition of meat
PRODUCT WATER PROTEIN FAT MINERALSBEEF (LEAN) 75.0 22.3 1.8 1.2BEEF (CARCASS) 54.7 16.5 28.0 0.8PORK (LEAN) 75.1 22.8 1.2 1.0PORK (CARCASS) 41.1 11.2 47.0 0.6CHICKEN 75.0 22.5 0.9 1.2FRANKFURTER 63.0 14.0 19.8 0.3LIVER SAUSAGE 45.8 12.1 38.1LIVER PATE 53.9 16.2 25.6 1.8SALAMI 33.9 24.8 37.5
Common processes used by meat industry
Heat treatment Lowering of water activity (aw) Reduction of pH Use of chemical preservatives Use of modified atmospheres
Hurdle technology
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Heat Treatment
Heat treatment
Heat treatment of processed meat productsserves two main purposes: Enhancement of desirable texture,
flavour and colour Reduction of microbial content Ready to eat Appropriate shelf life
Heat treatment
Can be two-stage heat treatment: As part of processing Prior to consumption
Frankfurters raw-cooked sausage Initial process used to achieve desired: Texture Flavour Colour
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Heat treatment
Some products subject to two initial heattreatments Raw materials pre-cooked Further processed For example black pudding.
Important to be clear about the nature of heattreatment on inspection.
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Thermal processing
Different degrees of preservation: Sterilisation Complete destruction of micro-organisms 121°C for 15 mins
Commercial sterility All pathogens, toxins and spoilage bacteria destroyed. Some thermoduric survivors
Pasteurisation Kills pathogens Extends shelf life
Blanching Inactivates key enzymes Reduce bacterial load
Effect of Heat on Micro-Organisms
Application of heat sufficient to kill microorganisms: Results in % kill / unit time
Characterised by “D”, “Z” and “F” values.
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D Values
Decimal reduction time Varies for different
organisms Quoted at a particular
temperature ie “D121” Cells die more rapidly
at higher temperature
1
10
100
1000
0 5 10 15
Surv
ivin
g Sp
ores
Heating Time (Min)
D Value 5 Mins
D Values
This is the time taken to reduce micropopulation by 90% Higher “D” Value indicates higher heat resistance
NOTE: More Micro orgs in raw material,longer it will take to get to desired level
D Values
Can be expressed as 5D, 8D or 12 D etc 8D process will reduce numbers by 100,000,000 5D and 8D commonly used, 12D used for low acid canning
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Heat Resistance of Food PoisoningBacteria
Organism D Value (seconds)Campylobacter sp D55 = 60
Salmonella sp D60 = 34.8
Listeria sp D 71.7 = 3.3
Staph. Aureus D60 = 120 – 2000D71.7 = 4.1
Clostridium botulinum
Escherichia coli
D121 = 12.6D62.8 = 7.8
Z Value Change in ºC required to
bring about a 10 foldchange in D
aka Temperaturecoefficient of destruction
D and Z valuescharacterise the heatresistance of an organism 1
10
100
1000
90 110 120 130
D v
alue
s
Temperature
Z Values
Destruction of E.coli o157 in burgersACMSF 2007
Temperature °C ACMSFRecommendation
6 D reductionZ 6°C
60 45 mins 93 mins
65 10 mins 13.6 mins
70 2 mins 2 mins
75 30 secs 18 secs
80 6 secs 3 secs
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F Value
Total time/temp received by a food.
F0 = F121
Number of minutes at 121°C to heat food
Minimum Safe Process “Botulinum Cook” Applied to low acid canned foods Necessary to achieve 12D reduction of
Clostridium botulinum spores At 121ºC D value for Cl.botulinum is 0.21
minutes 12 x 0.21 = 2.52 minutes (ie F0 of 3.0) F0 values will vary according to food type etc Sufficient margin of safety built in.
Food safety controls: Thermal Process
Thermal process must be adequate to controlidentified microbial hazards: Salmonella spp E.coli o157 Listeria spp Staph.aureus etc.
Where necessary: C.botulinum
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Food safety controls: Thermal Process
Where risk from C.botulinum considered high 90°C for 10 minutes or equivalent
Where risk from C.botulinum not consideredhigh: 70°C for 2 minutes or equivalent
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Lowering water activity
aw - Water Activity
Measure of amount of liquid water availablefor microbial growth
Pure water = 1.0 Presence of solutes = <1.0 Enables prediction of possible bacterial
growth in food Bacteria generally require high aw for growth
Typical aw values for meat products
PRODUCT aw RANGEFRESH MEAT 0.99 (0.99 – 0.98)COOKED HAM 0.97 (0.98 – 0.96)RAW – COOKED SAUSAGES 0.97 (0.98 – 0.93)LIVER SAUSAGE 0.96 (0.97 – 0.95)BLOOD SAUSAGE 0.96 (0.97 – 0.86)RAW FERMENTED HAM 0.92 (0.96 – 0.80)RAW FERMENTED SAUSAGES 0.91 (0.96 – 0.70)DRIED MEAT 0.70 (0.90 – 0.60)
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aw values for limiting microbial growthMICROORGANISM aw
Pseudomonas 0.93E.coli 0.93Salmonella spp 0.91 – 0.95Listeria 0.93Clostridium botulinum (proteolytic) 0.94Clostridium botulinum (non-proteolytic) 0.97Clostridium perfringens 0.93 – 0.95Bacillus species 0.90 – 0.95Staph aureus 0.86 – 0.90Most yeasts 0.87 – 0.90Most moulds 0.80 – 0.85
Reduction of pH
Effects of pH on microbial growth Acidophile Lactobacillus acidophilus
Neutrophile Salmonella spp
Alkaliphile Nitrobacter spp
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Reduction of pH
PRODUCT pHRaw fermented sausage 4.5 – 5.2Beef 5.4 – 6.0Pork 5.5 – 6.2Canned meats 5.8 – 6.2Biltong 5.8Ham 5.9 – 6.1Black pudding 6.5 – 6.8
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Typical pH values for some foodspH Range Food pHLow acid (pH 7.0 –5.5)
Medium acid (pH 5.5 – 4.5)
Acid (pH 4.5 – 3.7)
High acid (pH <3.7)
MilkCheddar CheeseBaconRed MeatHamPoultryFishButterBreadCottage cheeseGreen beansBananasMayonnaiseTomatoesCanned pickles, fruitjuiceSauerkrautCitrus fruitApples
6.3 – 6.55.95.6 – 6.65.4 – 6.25.9 – 6.15.6 – 6.46.6 – 6.86.1 – 6.45.3 – 5.84.54.6 – 5.54.5 – 5.23.0 – 4.14.03.5 – 3.93.1 – 3.33.0 – 3.52.9 – 3.3
Use of chemical preservatives
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Effects of osmotic pressure on microbial growth
Typical NaCl levels in some Foods
Food NaCl (%)BaconHam (canned)Ham (raw)Smoked FishCheddar CheeseRaw FishRaw Meat –BeefLambChickenTurkey
3.0 – 4.83.22.6 – 3.61.9 – 4.81.6 – 1.80.3
0.20.20.20.2
Use of modified atmospheres
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Vacuum and modified atmosphere packaging
MAP - a definition“packaging of a food product in something other than air”Includes:
vacuum packaged (VP) modified atmosphere packaged (MAP) controlled atmosphere packaged (CAP) gas packed/gas flushed sous-vide Also any other condition which will result in a similar reduction of
oxygen e.g. deep-filled or hermetically sealed products
Vacuum Packing (VP)
Food Preservation technique where: atmospheric air is removed vacuum maintained by integrity of pack
Vacuum Packing (VP)Advantages
Increased shelf life Equipment relatively
inexpensive Freshness and flavour
maintained Moisture retained Rancidity reduced Infestation eliminated Wastage reduced Portion control and
presentation
Disadvantages Temperature control
required Inherent food safety risks Not suitable for soft
products Undesirable colour
changes in red meat
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Modified Atmosphere Packaging (MAP)
Food preservation technique whereby: the composition of the atmosphere surrounding
the food different from the normal composition ofthe air.
Process involves Removal of air Replacement with mixture of Carbon dioxide Nitrogen Oxygen
Gas mixture varies for type of food
Gases for MAP
CO2
has biostatic properties against manypsychrotrophic bacteria
O2
inhibits anaerobes, develops bright red colour inmeat
N2
inert, used as a filler to prevent collapse ofpackaging.
Effects of MAP on Micro-organisms
CO2 Increases lagphase
Gram -ve moresensitive to CO2
CO2 can inhibitgrowth of spoilagemoulds
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Advantages / Disadvantages of MAP
Advantages Increased shelf life Reduced distribution
costs High quality product Reduced need for
additives Minimisation of waste
Disadvantages Expensive Temperature control
required Different gases required
per product Special equipment
required Inherent food safety
risks
Food Safety Concerns
Food Safety Concerns
Absence of oxygen Growth of Clostridium botulinum favoured Listeria monocytogenes, Staph aureus
Primary Food Safety Concern: Increased probability of C.botulinum toxin
formation before spoilage bacteria make productunacceptable to the consumer
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Clostridium botulinum
Psychrotrophic C.botulinum Important in VP/MAP chilled foods
Types B,E,F can grow at 3.3°C As shelf life increases - more time to grow Toxin formation increases with temperature
Characteristics of Group I and IIC. botulinum.Characteristic* Group I
(proteolytic)(A & B)
Group II(non-proteolytic)(B, E & F)
Minimum temperature forgrowth (oC)
10 3.3
Maximum Temperature forgrowth (oC)
48 45
Inhibitory pH 4.6 5.0
Inhibitory NaCl concentration(%)
10 5
Inhibitory aw 0.94 0.97
*Value when other conditions are optimal for growth
Assessment of Risk from C.botulinum
Basic principles: C.botulinum must be present Inadequate processing or unprocessed product Product must support growth and toxin formation Intrinsic Extrinsic
Product must be ingested.
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Vacuum Packaging of Red Meat
Commonly used for distribution and storage ofprimal cuts of meat.
Cut will appear dark purple. Upon opening pack myoglobin will be oxygenated to
oxymyoglobin (Bright red). Vacuum packed primal cuts of beef with normal
pH can be stored for several weeks at 0oC Not suitable for comminuted meats
MAP- Gas Flushing of red meat
Air is removed from the pack and replacedwith a control atmosphere. Inhibits the growth of aerobic spoilage bacteria
such as Pseudomonas spp. Lactic acid bacteriapredominate.
Raw red meat attractive red colour due to theformation of oxymyoglobin
Effectiveness is dependant on goodtemperature control and good quality meat
Equipment required is expensive
Typical controlling factors
Temperature No growth of C.botulinum at 3°C Heat treatment 90°C for 10 minutes
pH 5 or less throughout food
Salt level 3.5% throughout food
Water availability (aw) 0.97 or less throughout food
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Listeria control strategies
Meat products vulnerable to the outgrowth ofListeria monocytogenes which may be present inthe environment.
FBOs should be encouraged to: Undertake environmental investigation, based on HACCP
principles, to determine the likely occurrence of listeriaand
introduce effective controls to prevent the contaminationof finished products.
This investigation should include, but not be limited to, aconsideration of the use of environmental swabs.
Listeria control
Guidance issued byFSAI
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References
http://www.fao.org/docrep/010/ai407e/AI407E00.htm
Questions?
Dr Andy Bowles FIFSTSpecialist food law solicitor
01603 274486
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