When there are exposed to oxygen, foodstuffs deteriorate rapidly. The protective atmosphere packaging allows to avoid this issue. Let’s look at this of conditionning is called the MAP (Modified Atmosphere Packaging).
Replace air by others gases
The protective atmosphere packaging consits in protecting the foods from any contact with air by replacing it with others gases, from industrial origin. In pratice, this technique is frequently coupled to a low temperature storage.
In general, the gas used is a mix, adapted to the type of food to protect. The different gases used for modified atmosphere packaging are listed in European Directive 2008/84/CE:
● Nitrogen (N2) prevents pigments oxydation and bacterial proliferation ● Carbon dioxide (CO2) limits the growth of bacteria and molds. ● Oxygen (O2) preserves the color of the meat and prevents the proliferation of germs ● Argon (Ar) acts as nitrogen, while reducing for enzymatic decomposition
Ntrogen helps preserve dry goods while oxygen protects fresh fruits and vegetables, meat and fish. As for argon, it is used to package sensitive products such as wine. The gases used can be produced on the user’s site by means of a specific generator (nitrogen generator, oxygen generator, etc) optionally associated to a mixer.
An optimal food preservation
Protective atmosphere packaging has many advantages for the preservation of foodstuffs:
• It prolongs their freshness • He moves back the shelf life • It facilitates inventory management across the distribution chain • It guarantees hygiene by reducing the risk of bacterial contamination • It allows a better presentation of products, more attractive for the consumer
This mode of conditioning, on the other hand, requires a strict respect of the cold chain, and is not suitable for all types of food.
The packaging process
The protective atmosphere packaging has several stages.
It starts with the choice of the packaging itself, which must be adapted to the foodstuffs to be protected. Some foods require permeable films, which allows them to breathe. This is the case of fresh fruits and vegetables. Others, on the contrary, must be wrapped in totally hermetic films. This is the case with meat and fish.
The preservative gas is then injected into the package. For this, two techniques are possible:
● gas scavenging: it consists in injecting gas into the packaging until it has replaced the air.
● the compensated vacuum: it consists in removing the air from the packaging before injecting the gas.
Gaseous sweep is suitable for fragile foods. The compensated vacuum is better suited for products able to withstand the pressure generated by vacuum.
Finally, once packaged, the food is carefully controlled. Various techniques make it possible to perform this control : the tightness of the packaging can be tested by using vacuum measurement instruments, or the gas contained in the package can be analyzed.