Nitrogen Flushing Protects and Preserves Foods

Potato chips are kept fresh by nitrogen gas.
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Let's face it. We consume a lot of processed foods every day. They're convenient and certainly not all processed foods are bad. Processed foods need a lot of protection -- from the processing plant to the grocery store, and to your kitchen. Plus, you may need to store them for awhile before you use them.

When certain processed foods are exposed to oxygen, they can deteriorate - fats go rancid, discoloration occurs and the food spoils.

 Oxygen can be removed from the packaging by removing all of the air with a vacuum, which will increase the shelf life of the food packed inside.

Regular vacuum packaging works fine for sturdy solid foods like beef jerky and fresh meat, but it doesn't work well for foods that are delicate, like powders, snack chips, and crackers. These foods need protection during transportation so that they won't be crushed or broken. 

When you've picked up a bag of chips at the grocery store, you've probably noticed the bag is puffed and filled with 'air.' But it's not exactly like the air we breathe -- the package doesn't contain oxygen.

Most of these delicate foods are protected by a process called nitrogen flushing. Which may sound scary, but it's totally safe. In fact, nitrogen flushing is an excellent preservation method used to protect packaged foods such as coffee beans, nuts, rice cakes, snack crackers and chips.

 

Food manufacturers use machines that force the regular oxygen-rich air out of the packages and immediately fill them with nitrogen gas, and seal them tight. Nitrogen doesn't react with food like oxygen does, so foods stay fresher longer and it doesn't affect the flavor or texture of the food. And don't worry about the nitrogen - you're exposed to nitrogen constantly because it makes up about 70 percent of the air you breathe.

The nitrogen-filled packages help to protect the delicate foods inside. Of course, once you open the bags, the food inside is no longer protected and will start to deteriorate. But you can maintain some of the freshness by keeping the package closed with a twist tie or clip, or by placing the food in a resealable container.

Sources:

Lloyd MA, Hess SJ, Drake MA. "Effect of nitrogen flushing and storage temperature on flavor and shelf-life of whole milk powder." J Dairy Sci. 2009 Jun;92(6):2409-22. doi: 10.3168/jds.2008-1714. Accessed February 19, 2016. http://www.journalofdairyscience.org/article/S0022-0302(09)70556-9/abstract.

Marasca E, Greetham D, Herring SD, Fisk ID. "Impact of nitrogen flushing and oil choice on the progression of lipid oxidation in unwashed fried sliced potato crisps." Food Chem. 2016 May 15;199:81-6. doi: 10.1016/j.foodchem.2015.11.136. Epub 2015 Nov 30. Accessed February 19, 2016. http://www.sciencedirect.com/science/article/pii/S0308814615302715.

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