MAP Packaging: the complete guide to modified atmosphere

How MAP works

The machine evacuates air from the container, then flushes the predefined gas mixture before hermetically sealing. The most common gases are CO₂, N₂ and O₂, combined in different proportions depending on the product. The pack thus maintains a controlled environment that slows bacterial growth and oxidation.

• CO₂ (carbon dioxide): bacteriostatic and fungicidal action
• N₂ (nitrogen): inert, maintains pack volume
• O₂ (oxygen): preserves the red colour of fresh meat
• Typical red meat mix: 70% O₂ / 20% CO₂ / 10% N₂
• Typical fish mix: 40% CO₂ / 30% O₂ / 30% N₂

MAP vs vacuum: when to choose which

Vacuum is ideal for dense products that do not need to maintain shape: whole cold cuts, aged cheeses, boned meat. MAP is preferable when the product must not be compressed or when the red colour of meat needs to be preserved at the counter.

Economically, MAP requires continuous consumption of technical gases and rigid or semi-rigid packs, while vacuum uses flexible pouches at lower cost.

• MAP: fresh products that must not be compressed
• Vacuum: cold cuts, aged cheeses, whole cuts
• MAP: visually appealing shelf life at point of sale
• Vacuum: lower pack cost, higher storage density

Machines for MAP packaging

Tray sealers are the most suitable machines for MAP: they place the product in the tray, evacuate air and flush gas before sealing the top film. For high volumes, thermoformers form the tray directly in-line from the bottom film.

• Manual/semi-auto tray sealer: up to 6-8 trays/cycle
• Automatic in-line tray sealer: 20-40 trays/min
• Thermoformer: forming + filling + MAP + sealing in continuous flow
• Vacuum chamber with MAP: versatile for mixed production