An introduction to Modified Atmosphere
Packaging (MAP) and food shelf life extension
Steve Baker – Technical Specialist
Gas applications in food and beverage sector
Red meat
Poultry
Seafood
Prep. foods
Fruits
Vegetables
Bakery
Dairy/Liquids
Snack Foods
Fats/Oils
Soft Drink
Breweries
Wineries
PREPARE
SPRAY CRYST.
CARBONATIONDEOXYGENATION
FLOUR CHILLING
CHILLING
HYDRO.
PRESERVE
FREEZING ANDCHILLING
CRYO-CRYS
DISTRIBUTION
TRANSP.COOLING
ATMOSP.CONTROL
CLEAN-UP
WASTE
WATER
TREATMENT
PACKAGING
MAP
LN DISP. &
INERTING
MAP
INERTING
RETAIL/CONSUMER
HOSPI-TALITY
FRESHIn grocery
STORAGE/TRANSPORT
CA STUNNING
CA/SPARG
BLANKET/SPARGE
FUMIGANT
FUMIGANT
GROW/HARVEST
OXYGEN
CHILLING
GREENHOUSE
What is modified atmosphere packaging?
A preservation technique used to prolong the shelf life of processed or fresh food by changing the composition of the atmosphere surrounding the food in the package.
Common alternative preservation technologies:
Vacuum packaging: The removal of all the air within the package
Canning Preserving food from spoilage by storing it in containers that are hermetically sealed and then sterilized by heat
Pasteurization A method of treating food by heating it to a certain point to kill pathogens
Refrigeration Extend shelf life via storage in low temperature but above freezing point
Freezing Extend shelf life via lowering temperature below freezing point
Comparing food preservation methods
Method Advantages DisadvantagesDrying Concentrated form of food
Inhibits microbial growth Retains most nutrients
Loss of some nutrients
Changes product taste
Chemical Preservatives (salt, smoking, pickling)
Prevent microbial growth
No loss of nutrients.
Not ‘natural’
Potential for allergic risk
High Heat pasteurizing Inactivates autolytic enzymes Destroys microorganisms
Loss of heat-sensitive nutrients
Loss of food flavor & taste
Vacuum Packing Slows microbial growth Prevents oxidation
Limited to suitable products
Does not prevent anaerobic microbial growth
Canning Destroys microorganisms Water-soluble nutrients lost into liquid in can. Lost flavor & taste
Expensive capital & package cost
Refrigeration Slows microbial growth Slow loss of nutrients over time.
Limited shelf life time
Freezing Prevents microbial growth Good retention of nutrients
Thawing can reduce product quality.
Not perceived as ‘natural’.
MAP – gas flushing Slows & inhibit microbial growth Natural preservation method
Suitable for variety of foods
Limited length of shelf-life time
Introducing hurdles
Freshness
Time
Frozen
Canned
Ambient
temperature
Chilled
Chilled +
modified
atmosphere
General effects of different preservation methods on perishable food
Shelf life assessment
How long will the product remain fit for consumption?
For a food processor to be able to determine the shelf life of a product they will need to have
a good knowledge of the product, its composition and the factors involved in its spoilage.
Independent micro-biological testing laboratories can assist with this assessment.
Gases used in MAP
OXYGEN
A very reactive gas. Used in instances where colour retention is required (eg red meat),
or where air is replaced by a reduced oxygen atmosphere (eg in respiring produce).
Prevents anaerobic growth conditions (eg packaging of white fish).
NITROGEN
An inert gas with low solubility in water. Used primarily to displace air / oxygen from
packs, preventing rancidity (eg in snack foods). Low solubility in water, therefore used
in conjunction with CO2 where pack collapse occurs due to CO2 absorption.
CARBON DIOXIDE
Dissolves easily in water. Slightly acidic. Powerful inhibitory effect on microbial growth,
particularly effective against pseudomonas, which cause off-flavours and colours in
protein foods. Effect increases with reduced temperature, and generally needs to be
used in concentrations of at least 20%.
Recommending gas mixtures
Product Recommended Typical Shelf Life in:-Gas Mixture Air MAP
Cooked sliced meat 30% CO2 2-4 days 2-5 weeks
70% N2
Diced raw beef 80% O2 2-4 days 5-8 days
20% CO2
EU - Approved food contact use
Carbon Dioxide E290
Nitrogen E941
Oxygen E948
Labelling legal Obligation
Under EU Law, MAP packaged foods must be labelled with the phrase:-
‘Packaged in a protective atmosphere’
CO2 – the extra hurdle
Hurdle concept
aw pH temp gas (CO2)
The “Hurdle ” concept – Not just gas alone
The general principle of using multiple shelf-life solutions collectively to reduce the risk of spoilage
Perfect food comes in perfect packaging
MAP gas mixture vs shelf life recommendations
Packaging machines
Operational practicalities
Deep-drawing machine
Tray-sealer
Bag-sealer
Vertical flow-pack
Horizontal flow-pack
Vacuum chamber
BOC Online
www.boconline.co.uk