What gases are used in Modified Atmosphere Packaging?

Typical gases used in Modified Atmosphere Packaging (MAP) include:

• Nitrogen (N2) 
• Carbon dioxide (CO2) 
• Oxygen (O) 
• Argon (Ar) 
• Hydrogen (H2) and helium (He)
• Carbon monoxide (CO).

Let’s look at each in detail.

Nitrogen (N2)

Nitrogen is an inert (chemically stable, unlikely to react with other substances), high-purity gas commonly used in Modified Atmosphere Packaging to replace atmospheric air, particularly oxygen.

It helps prevent oxidation and slow the growth of microbes that need oxygen to thrive, keeping products looking and tasting fresh. 

Nitrogen is often added to packages as a filler gas because it diffuses slowly through plastic films, helping maintain the desired gas combination for longer. 

It also maintains pressure inside the package, helping it retain its shape. This is essential for product display. Expanded or deflated packages can topple over in a warehouse or on supermarket shelves and look defective to consumers. 

Foods like crisps, dry pasta and rice, and roasted coffee are packaged with a 100% nitrogen content.

Nitrogen is often combined in small to high percentages (20 to 80%) with gases like carbon dioxide and oxygen to help keep products like baked goods, dried fruit, cheese, and processed meats fresh.

Carbon dioxide (CO2)

Carbon dioxide is a reactive gas - it can chemically interact with other substances - often used in Modified Atmosphere Packaging because it disrupts microbial metabolism (when bacteria and other microbes break down nutrients to grow).

It slows oxidation and the growth of most aerobic bacteria and moulds, which helps keep products looking fresh when on display.

As a rule of thumb, the higher the CO2 concentration, the longer a product lasts. However, excessive amounts can make some foods high in water or fat - like soft cheeses, ready meals, and fresh pasta - taste sour. 

Using carbon dioxide poses two potential challenges. Foods high in water or fat can absorb the CO2, causing the packaging to collapse. 

These problems can easily be solved by adding inert filler gases like nitrogen to the packaging. Nitrogen dilutes the CO2 concentration and maintains internal pressure.

Carbon dioxide is used in small to medium concentrations (20 to 60%) to extend the shelf life of foodstuffs like poultry, soft or semi-hard cheese, fresh pasta, and cooked meats.

Oxygen (O2)

Oxygen is a highly reactive gas commonly used in Modified Atmosphere Packaging because it prevents anaerobic metabolism (when cells generate energy without oxygen).

In some instances, a high concentration of oxygen (60 to 80%) is used to maintain the bright colour of red meat by stabilising oxymyoglobin (its pigment).

However, oxygen is often reduced or displaced in products like ready meals, white meat, and cheese to reduce oxidation, microbial growth, and flavour alteration.

Keeping oxygen levels between 2% and 5% helps fruits and vegetables maintain healthy respiration after harvest and prevents the switch to anaerobic metabolism, which can cause them to spoil, soften, or release unpleasant gases.

Because of its reactive nature, oxygen must be carefully controlled based on the product’s requirements.

Carbon monoxide (CO)

Carbon monoxide (CO) is a reactive gas that, in minimal amounts, helps preserve the colour of meat and fish, preventing them from turning brown. 

Carbon monoxide is banned in several countries, including the EU and the UK, in food packaging. However, it is used in the United States, Canada, and parts of Asia and Latin America to preserve beef, pork, tuna, and other fish.

Argon (Ar) - Experimental

Argon is an inert gas similar to nitrogen, so it can be used as a substitute. 

Argon is heavier than nitrogen, so it can form a denser protective layer over a product, reducing oxygen more efficiently. For this reason, argon can be very effective in protecting fresh produce, like leafy greens and sprouts, from spoilage.

Some studies suggest argon might help slow down the growth of enzymes linked to ripening and spoilage and reduce how fast vegetables breathe, possibly keeping them fresher a little longer. However, the effects are minor and vary between different types of produce. 

Because argon is more expensive than nitrogen and doesn’t offer significant added benefits,  it’s rarely used outside high-value or experimental packaging.

Hydrogen (H2) and helium (He) - Experimental

Hydrogen and helium are occasionally used in Modified Atmosphere Packaging to trace gases in some leak detection systems. Their extremely small molecules can quickly escape through even tiny packaging defects, helping you pinpoint leaks quickly and accurately.

Their use is uncommon because they are costly, difficult to handle, and require specialist equipment and trained staff. They are mainly used in high-risk or high-value packaging quality assurance processes. Most leak testing relies on detecting O2 and CO2. 

When it comes to a complex process like Modified Atmosphere Packaging, it’s essential to identify the right combination and concentration of gases to preserve your product. Different foods react uniquely to specific gas mixtures, so maintaining freshness and quality relies on precise atmospheric control.

Too much or too little of a gas can lead to spoilage, texture alterations, changes in flavour, and even food safety risks. 

Luckily, today’s gas and leak testing tools are ultra-precise. 

Modern packaging testing instruments can conduct exact gas, leak, and burst tests sequentially, making MAP and quality control more effective and time-efficient. The latest flow optimisers on the market help minimise gas usage while ensuring freshness, safety, and hygiene.