Nitrogen Flush: Keeping Your Favorite Snacks Fresh and Crispy

Despite playing a key role in the preservation of many of our favorite foods, like potato chips, most people have probably never heard of nitrogen flushing. We’re here to change that. In this Union Kitchen resource guide, we’ll go over the science, history, process, and application of nitrogen flush in packaged foods. By the end, you should know the magic behind preserving your favorite packaged snack! 

To start out, what exactly is a nitrogen flush? A nitrogen flush is the process of using nitrogen gas to remove oxygen from food packaging, thus increasing its shelf life. Because nitrogen is the heavier gas, it sinks to the bottom, pushing out the oxygen. It’s similar to placing a stone in a cup of water, causing the water to spill out. This is critical, as oxygen causes food decay by creating an ideal environment for decomposing bacteria and fungi to thrive. 

To illustrate how this works, let’s use a Union Kitchen favorite, Snacklins, as an example. One of the last steps in manufacturing a Snacklin is bagging. Packaging can support or take away from the shelf life of a product. 

When the Snacklin’s team bags their plant-based chips, they run the risk of trapping oxygen inside the bag. Left alone, this could result in the chips going bad sooner than normal. This could be a serious problem, if a customer opens this bag, only to discover discolored, rotting chips. To stop this from happening, Snacklins uses a nitrogen flush.

The technique of controlling decay by modifying the storage atmosphere is relatively new compared to more ancient food-preservation techniques, such as salting or dehydrating. While Jacques Etienne Berard, a professor at the School of Pharmacy in Montpellier, France, reported delayed ripening of fruit and increased shelf life in low-oxygen storage conditions in 1821, this practice wouldn’t become a wide-spread for another hundred plus years. In the 1930s, shipping companies began to use CO2 to transport fruit. Finally, gas-flushed, oxygen-free packaging would arrive on store shelves forty years later in the 1970s. The demand for gas flushing has grown continuously since then.

How exactly does one successfully complete a nitrogen flush? First, place your food into their respective packaging. Easy enough. Next you’ll need to employ a specially designed sealer, which will remove the air from the packaging. A machine will then need to quickly replace the oxygen with nitrogen. Not only does this replace the decay-causing oxygen with nitrogen, but it also creates a protective cushion for fragile foods. Grab a bag of chips and feel the air in it. That’s the protective layer of nitrogen. This is helpful for transportation, as the food might break or be crushed without it. It’s no wonder then why many snack and food manufacturers, such as PepsiCo, so commonly use this technique.

Wondering if a nitrogen flush system is a good investment for your business? There are several factors you should consider before deciding. 

  1. Does your food spoil easily? Foods that use fresh ingredients but forgo using artificial preservatives or dehydration are at risk of spoiling relatively quickly due to oxygen. Many of the ready-made salads you buy at grocery stores, for example, would spoil quickly if not for nitrogen flush. If this sounds a bit like your product, then it might be worth taking another look. 

  2. What type of packaging are you using? The second thing to look at is the packaging you use. Businesses that place their product in air-sealed environments, such as bags or air-tight plastic containers, should probably look into investing into a nitrogen flush system. As previously mentioned, this not only removes the oxygen, but also creates a protective cushion. 

  3. How are you storing your food? Finally, you’re going to want to look at how you store your product. Packaged foods that are stored in dry, room-temperature environments, like store shelves, will likely benefit from a nitrogen flush. Dry storage units typically lack the cold air, as there would be in a refrigerator or freezer, necessary to slow the food’s decay by freezing the water vapor, which decomposing organisms normally thrive in.

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By reading through this guide, you should now have an idea about whether or not you want to invest in a nitrogen flush. Those who have decided that this would be the right move for their business can find the necessary equipment and the gas from a local gas company. Check with them for pricing and availability. For more useful business resources, check out more of Union Kitchen Resource Guides.