What Is Modified Atmosphere Packaging?

Regardless of your refrigeration or packaging system, food is always subject to spoiling. The most common examples of food spoilage include milk curdling and fermenting, fruit browning or rotting, and nasty mold spore growth on bread.

To combat this, the food packaging industry uses a processing system known as modified atmosphere packaging (MAP) to package food. This packaging process aims to inhibit unwanted changes brought about by the spoiling process and extend the shelf life of packaged foods. Consumer demand for healthy food options is ever increasing, as is the need for packaging choices to supply desirable and fresh food alternatives. With this demand comes the need to provide a consistent quality control method that can result in less food spoilage.

By expanding the use of modified atmosphere packaging systems to a variety of food products this can inhibit spoilage and allocate fresh food alternatives into a broader scope of markets. The modified atmosphere packaging process achieves this goal without depending on using food stabilizers or chemical additives.

How Does Modified Atmosphere Packaging Protect Foods?

The food processing system for modified atmosphere packaging is also referred to as gas flushing, protective atmosphere packaging, or reduced oxygen packaging. This process involves exchanging the atmosphere within food packaging with natural gases in precise proportions. This method is proven to inhibit the oxidation process and prevent any microbes from flourishing on the food product.

By flushing or changing the gaseous atmosphere that exists within a packaged good, it permits a much longer shelf-life by preserving the food.

Nitrogen is the perfect solution to displacing the oxygen levels that lead to the spoilage of various foods. The use of nitrogen in gas flushing creates the desired controlled proportions that inhibit the oxidation process and successfully modify the atmosphere in which the food is packaged to significantly extend the shelf life of the food product.

Partner with On Site Gas Systems

When it comes to dependable nitrogen generators, On Site Gas Systems is the leader in customizing a system suited for your operations. On Site Gas supplies manufacturers around the globe with top-notch nitrogen generators made in their own ISO-certified factory. We are reputed for our best-in-class nitrogen generation systems that are both reliable and cost-effective.

From PSA nitrogen generators and membrane nitrogen gas generators to custom nitrogen engineered systems, On Site Gas covers a breadth of manufacturing needs for modified atmosphere packaging for the food industry. Contact our team to learn more about our nitrogen generator systems.

The Types of Nitrogen Purging Systems


Impurities, oxidation, and unwanted vapors (or gases) can occur within many industrial manufacturing systems. The presence of these gases runs the risk of creating a hazardous or explosive environment within the system. Nitrogen purging is the safest method for eradicating any potentially damaging or threatening ambiance by using a technique that implements an inert nitrogen atmosphere.

Industries such as pharmaceuticals, oil and gas, and chemicals integrate the process of nitrogen purging as an essential part of their daily operation. Where the presence and the contamination of threatening gases are likely, a nitrogen purge system is an absolute requisite.

The Method of the Nitrogen Purge

Nitrogen purging is a method of successful displacement of any dangerous gas, harmful vapor, damaging oxygen, or unwanted moisture to ensure the environment within the equipment or a system is dry.

Purging is a well-established and long recognized use of nitrogen gas. For example, tanks that are full of hydrocarbon liquids have vapor space that exists at the top of the tank where hydrocarbon vapors gather. When emptying an atmospheric tank, the air is drained and can become subject to friction or static electricity, which can easily ignite or explode. A nitrogen purging system, however, functions to eradicate the vapor space with nitrogen gas, thwarting the hazard of explosion.

A nitrogen purging system is ideal for substances that attract water by either absorption or adsorption. Substances like this include ethanol, glycerin, methanol, and concentrations of sulfuric acid, lye, or honey.

The Merits of a Nitrogen Purging System

The main objective of a nitrogen purging system is to purify pipes and other components in a manufacturing process that can house various contaminants. Nitrogen is a reliable inert gas that is both economical and safe. The benefit of a nitrogen purge is that it eradicates the risks associated with unsafe elements, including oxygen. It creates a more stable, dry, and safe environment. Depending on the method of nitrogen purging used, the nitrogen may flow at either low or high pressures.

What are the Different Kinds of Nitrogen Purging Systems?

There are four main processes for a nitrogen purge, each of which requires different equipment. The four processes involved include:

  • Displacement purging
  • Dilution purging
  • Pressure transfer of liquids
  • Pressure hold vacuum process

Displacement purging

Manufacturing equipment that is designed with a basic cross-section (such as pipelines) is ideal for displacement purging. This functions by using a scraping piston (or pig) which is thrust by the pressure of the nitrogen. As the scraping piston propels through the line, it purges the unwanted matter. The volume of the pipeline determines the amount of nitrogen that is needed to perform this task. There is no mixing involved (as in the dilution method) and it is possible to separate nitrogen and additional material with an inert fluid.

Dilution purging

Systems that are more complex than a straightforward pipeline, and equipment that includes cross-sections, are ideal for dilution purging. An example of this includes columns, reactors, or kilns. The nitrogen is mixed with the specific gas needed to be purged in the system. The mixture is purged from the entry point to the exit point. Emphasis is placed on the location(s) of these two points. Diluting combined with displacing the unwanted matter results in the creation of a more inert atmosphere.

Pressure transfer of liquids

In some instances, the objective is to move liquids without the use of a pump. Nitrogen is the perfect choice to pressurize the headspace inside the container or system in order to do so. This is particularly useful where space is constricted or where materials that influence pump efficiency are present. By using the pressure transfer of liquids, the chance of oxidation is significantly reduced.

The pressure-hold vacuum process

There may be conditions present that prevent the nitrogen from sweeping away harmful substances. In this case, the container is instead pressurized with nitrogen. This creates the conditions for dilution to occur and the material is then vented. The pressure hold vacuum process is then repeated. This is an effective method for containers that have only one opening. The amount of nitrogen needed for this process is based on how many times pressurized purges are needed to reduce the unwanted contaminant to the desired level.

On Site Gas is the Leader in Nitrogen Purging Systems

On Site Gas is best-in-class when it comes to matching nitrogen purging systems to your needs. To learn more about which nitrogen purging system is best for you, consult with a member of our customer care team today. Our experts are here to help you choose the nitrogen purging solution that works for you.