While many consumers assume that gas flushing is new, it is a technique that has been around since the early part of the 1930s. It was originally used to transport fruit in large cargo ships where CO2 was flushed into the cargo holds to prevent the fruit from ripening and spoiling.
The first use of modified atmosphere packaging for consumer products wasn’t until the 1970s, and even then it was first used in Mexico before the rest of the world. Now, this method is used to preserve and extend the life of products from minimally processed foods to fresh fruits and vegetables or even coffee and fresh cuts of meat and fish.
How it Works
The original bagging or packing process for all foods undergoing modified atmosphere packaging is the same as with traditionally packed foods. However, just before the bag is sealed an inert gas is forced into the bag.
This inert gas will typically be a combination of gasses. They can include nitrogen, carbon dioxide and carbon monoxide in carefully controlled mixtures. This particular combination is known in the packing industry as Tri-Gas. It is also common to use nitrogen, mostly as a filler gas to create pillow packs or to add protection to food items. Argon is commonly used in modified atmosphere packaging for vegetables as it can slow down the chemical processes that create spoilage in the package.
This inert gas is heavier and denser than the oxygen in the air, so the inert gas mixture forces the lighter oxygen out of the package. This is where the term gas flushing originates. At that point, the bag is sealed, trapping the inert gas inside to prevent oxygen in the atmosphere from entering. Not all oxygen from the interior of the bag is removed, but there is not more than 3% for optimal preservation conditions.
