The principle
Modified atmosphere packaging helps maintain the characteristics of food, especially freshly packaged food, achieving a longer shelf life without the addition of preservatives.
A gas mixture replaces the ambient air by sweeping or in two stages, a vacuum followed by injection of the mixture into a low-permeability package.
| GAS / Expected Profit | N2 | CO2 | O2 | AR | HE |
|---|---|---|---|---|---|
| Mechanical resistance, volume | Yes | Yes | |||
| Color preservation | Yes | ||||
| Anti-oxidation | Yes | Yes | |||
| Solubility | Yes | ||||
| Acidification | Yes | ||||
| Anti-aerobic organisms | Yes | ||||
| Anti-anaerobic organisms | Yes | Yes | |||
| Attenuation of breathing | Yes | Yes | Yes | ||
| Abundance | |||||
| Leak detection | Yes |
Oxygen (O2), carbon dioxide (CO2) and nitrogen (N2) are generally used.
The table opposite shows the proportions of oxygen (O2), carbon dioxide (CO2), and nitrogen (N2) depending on the application. CO2 is the most important gas among the protective gases. At concentrations above 20%, CO2 can significantly reduce the growth of microbes. A high oxygen content in the packaging protective gas can prevent oxidation.
| O2 | CO2 | N2 | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Color preservation, anaerobic anti-organisms | Solubility, Acidification, Anti-aerobic organisms, Anti-anaerobic organisms, Attenuation of respiration | Mechanical resistance, volume, Anti-oxidation, Attenuation of breathing | |||||||
| Product | De | Average value | A | De | Average value | A | De | Average value | A |
| Raw red meat | 70% | 70% | 70% | 23% | 26% | 28% | 5% | 5% | 9% |
| Offal | 80% | 80% | 80% | 20% | 20% | 20% | 0% | 0% | 0% |
| Whole raw poultry | 0% | 0% | 0% | 30% | 30% | 30% | 70% | 70% | 70% |
| Raw skinless poultry | 0% | 0% | 0% | 20% | 25% | 30% | 70% | 75% | 80% |
| Cooked meat and sausages | 0% | 0% | 0% | 20% | 25% | 30% | 70% | 75% | 80% |
| Lean raw fish | 20% | 24% | 27% | 40% | 48% | 56% | 20% | 29% | 37% |
| Raw oily fish | 0% | 0% | 0% | 40% | 40% | 40% | 60% | 60% | 60% |
| Cooked / smoked fish | 0% | 0% | 0% | 30% | 45% | 60% | 40% | 55% | 70% |
| Shellfish and crustaceans | 30% | 30% | 30% | 40% | 40% | 40% | 30% | 30% | 30% |
| Hard cheeses | 0% | 0% | 0% | 30% | 65% | 100% | 0% | 35% | 70% |
| Soft-paste cheese | 0% | 0% | 0% | 10% | 25% | 40% | 60% | 75% | 90% |
| Sliced cheese | 0% | 0% | 0% | 30% | 35% | 40% | 60% | 65% | 70% |