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Vacuum packing or vacuum packaging is a method of packaging that removes air from the package prior to sealing. It can involve both rigid and flexible types of packaging. The intent is usually to remove oxygen from the container to extend the shelf life of foods and, with flexible package forms, to reduce the volume of the contents and package.
Vacuum packing reduces atmospheric oxygen, limiting the growth of aerobic bacteria or fungi, and preventing the evaporation of volatile components. It is also commonly used to store dry foods over a long period of time, such as cereals, nuts, cured meats, cheese, smoked fish, coffee, and potato chips (crisps). On a more short term basis, vacuum packing can also be used to store fresh foods, such as vegetables, meats, and liquids, because they inhibit bacterial growth.
Vacuum packing greatly reduces the bulk of non-food items. For example, clothing and bedding can be stored in bags evacuated with a domestic vacuum cleaner or a dedicated vacuum sealer. This technique is sometimes used to compact household waste, for example where a charge is made for each full bag collected.
Vacuum packaging delicate food items can be done by using an inert gas, such as nitrogen. This helps prevent crushing fragile items and delicate foods such as potato chips.
External sealers 
External vacuum sealers involve a bag being attached to the vacuum-sealing machine externally. The machine will remove the air and seal the bag, which is all done outside the machine.
Chamber sealers 
Chamber sealers require the entire product to be placed within the machine. Like external sealers, a plastic bag is typically used for packaging. Once the product is placed in the machine, the lid is closed and air is removed. Then, there is a heat seal inside the chamber that will seal the bag, after sealing the bag the chamber is refilled with air by the automatic opening of a vent to the outside. This oncoming pressure squeezes all remaining air in the bag. The lid is then opened and the product removed. Chamber sealers are typically used for higher-volume packaging, and also have the capability to vacuum seal liquids
Preventing freezer burn 
When foods are frozen without preparation, freezer burn can occur. It happens when the surface of the food is dehydrated, and this leads to a dried and leathery appearance. Freezer burn also ruins the flavor and texture of foods. Vacuum packing reduces freezer burn by preventing the food from exposure to the cold, dry air.
Sous-vide cooking 
Food safety 
In an oxygen-depleted environment, Anaerobic organisms can proliferate, potentially causing food safety problems. Vacuum packing is often used in combination with other packaging and food processing techniques.
- Soroka, W. Illustrated Glossary of Packaging Terminology (Second ed.). Institute of Packaging Professionals.
- Yam, K. L., "Encyclopedia of Packaging Technology", John Wiley & Sons, 2009, ISBN 978-0-470-08704-6