Food packaging

Modified atmosphere packaging (MAP) of food is a widespread application of gases and gas mixtures to maintain the freshness, flavour and appearance of food in the supply chain and retail outlets. At Coles, and other supermarkets in Australia, you will find many meats, dairy products and dried groceries that have been packed using MAP gas mixtures from Coregas. The process is also known as controlled atmosphere packaging, or CAP.

Three gases are most commonly used for modified atmosphere packaging: nitrogen, carbon dioxide and oxygen. For some applications, such as the packaging of dried goods, it would be common to use a pure gas such as nitrogen. For processed meats a gas mixture of nitrogen and carbon dioxide would be typical. The packaging of fish often uses a three-component mixture of nitrogen, oxygen and carbon dioxide (CO₂). In a few cases such as pork, the gas composition for wholesale storage of bulk product is different to the gas mixture used for retail packaging.

Example retail food packaging gas mixtures:

• Red meat           30% CO₂ balance oxygen
• Poultry              30% CO₂ balance nitrogen
• White fish          30% CO₂, 30% nitrogen balance carbon dioxide
• Oily fish             40% CO₂ balance nitrogen
• Fresh pasta        50% CO₂ balance nitrogen
• Bakery products  50% CO₂ balance nitrogen
• Hard cheese       100% CO₂
• Milk powder        100% nitrogen
• Dairy products    30% CO₂ balance nitrogen
• Prepared meals   30% CO₂ balance nitrogen
• Fruit and veg      5% oxygen, 5% CO₂ balance nitrogen

In smaller scale operations, pre-mixed food packaging gases in cylinders are preferred due to the low capital cost and high flexibility. When production volumes grow, it is often the case that cylinder packs with 6, 8 or 12 cylinders bundled together are used. These may either contain pre-mixed gas at the required concentration or might be pure gases which are blended on site using gas mixing equipment to create the required gas mixture composition.

For the highest scale of food packaging operations, liquefied gases are supplied whether from our Microbulk Systems or with bulk delivery. These are delivered in liquid form and are vapourised before use. They can either be used in their pure form or mixed on-site to the desired composition using gas-blending equipment.

Typical pure food grade gases for mix on site applications:

• Food grade oxygen
• Food grade nitrogen
• Food grade CO₂

Our national team of Coregas customer service engineers can assist you with bulk tank installations, gas supply piping and on-site gas mixing equipment. It's all part of the service.

In some countries it has historically been common practice to capture and compress smoke from an open wood fire into cylinders and use that as a food packaging gas. This product, known as "smoke gas" is rich in nitrogen, CO₂ and CO. It does, however, also contain a high water content and the mixing of the water, CO and CO₂ in the steel gas cylinder can cause corrosion cracking of the steel which can lead to rupture of the cylinder. So, this practice is regarded as totally unsafe in Australia.

Bubbles in your beer

In addition to packaging of feed products, carbon dioxide and mixtures of nitrogen and carbon dioxide are also used for storage and dispensing soft drinks and beer. Coregas offers a range of gas mixtures for this application, such as Corebrew 30 for smooth-flow beers such as Guinness and Kilkenny, and Corebrew 75 for draft beers.