What gas mix is right for our modified atmosphere package?

We get this question frequently, especially for companies new to modified atmosphere packaging.  While it’s impossible to give specific product advice, we can at least lay out some of the variables to keep in mind.

In many cases, the gas mix will differ based on 1) the product in question, 2) whether or not the item is for bulk shipment or storage, or for retail sale, and 3) whether the product is raw or cooked.

With the exception of raw red meat, raw offal, cooked poultry, and many types of fresh and whole fruit, the overall goal is usually to remove as much oxygen as possible.   

Many types of cheese, dairy, pasta, and bakery products use some percentage of CO2 in their packages.  In these types of products, the goal is to prevent staleness and inhibit bacteria, which have a harder time growing in the presence of CO2.

Fruits usually contain a low (1-10%) percentage of oxygen, and a CO2 level between 0% and 20%.  Since fruits continue to respire after packaging, the permeability of the packaging is also a component – many types of packaged fruit allow for a consistent passage of O2 and CO2 through the packaging membrane.

No matter which gas mix you choose, you need an analyzer which can accurately test the gas composition of your package, both after it’s packaged, and for shelf life testing.  MAP packaging equipment can introduce incorrect gas mixes, the packages themselves can leak (letting in ambient air), and understanding the respiratory nature of your product days, weeks, or months after they are packaged are all important components to shipping a product which has an appealing appearance, longer shelf-life, and is safer to consume.