Vacuum packing is a method of packaging that removes air from the package prior to sealing. This method involves placing items in a plastic film package, removing air from inside and sealing the package. Shrink film is sometimes used to have a tight fit to the contents. The intent of vacuum packing 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 it inhibits 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 products, using plastic bags, canisters, bottles, or mason jars, are available for home use. For delicate food items that might be crushed by the vacuum packing process (such as potato chips), an alternative is to replace the interior gas with nitrogen. This has the same effect of inhibiting deterioration due to the removal of oxygen.
Types
Edge, suction, and external vacuum 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. A heat sealer is often used to seal the pack. Typically these units use a dry piston vacuum pump which is often considered a "maintenance-free" pump. For sealing dry goods only, this is the preferred method. Moist foods are known to cause internal corrosion on these dry piston pumps.
Double-chamber vacuum sealers
Double-chamber sealers require the entire product to be placed in a plastic bag within the machine. Once the product is placed in the machine on the seal bar, the lid is closed and air is removed. Then a seal bar inside the chamber seals the product in 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. Double-chamber sealers are typically used for medium-volume packaging, and also have the capability to vacuum seal liquids. The lid generally swings from one side to another, increasing production speed over a single-chamber model. Double-chamber vacuum packaging machines generally have either spring-weighted lids or fully automatic lids. Double-chamber vacuum packaging machines are commonly used for:
Fresh meat Processed meat Cheese (hard and soft) Candy and chocolate
Rotary belt type vacuum sealers Rotary belt type vacuum packaging machine or vacuum sealer features the same function as the double-chamber vacuum packaging machine as a 'vacuum bag sealer'. But the rotary belt vacuum packaging machine is more convenient, as the belt rotates automatically while the bags are placed to the sealing bar and vacuum sealing process completed. The vacuumed and sealed bags are automatically unloaded, which obviously is more convenient. The packaging plate of the machine is adjustable to 4 degrees, which allows the vacuum packaging of food with soup and liquid. Rotary belt type packaging machines are commonly used for:
Fresh meat Processed meat Seafood Pickles Cheese (hard and soft) Candy and chocolate Any other packs that needs vacuum sealing, and the size of the pack is not too big.
Automatic belt vacuum chamber machines
Automatic belt chamber sealers require the entire product to be placed in a plastic bag or flow wrapped pouch within the machine. The product travels on the conveyor belt, it is automatically positioned in the machine on the seal bar, the lid is closed and air is removed. Then a seal bar inside the chamber seals the product in 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. Automatic belt vacuum chamber machines are typically used for high-speed packaging of large items, and also have the capability to vacuum seal liquids. The lid generally travels straight up and down. Automatic belt vacuum chamber packaging machines are commonly used for:
Fresh meat (large portions) Processed meat Large sausage logs Cheese (hard and soft)
Thermoforming HFFS vacuum packaging machines
Vacuum packaging in large production facilities can be done with thermoforming machines. These are Form-Fill-Seal style machines that form the package from rolls of packaging film (webbing). Products are loaded into the thermoformed pockets, the top web is laid and sealed under a vacuum, MAP (modified atmosphere), or skin packaging producing rapidly packaged products. Thermoforming can greatly increase packaging production speed. Thermoformed plastics can be customized for size, color, clarity, and shape to fit products perfectly, creating a consistent appearance. One of the most commonly used thermoformed plastics is PET, known for a high-strength barrier resistant to outside tampering and an ease of molding into designated designs and shapes. Some common uses for Thermoforming in vacuum packaging include:
Fresh and marinated meat Sausage Cheese Candy and chocolate Grain Grab-and-go snacks (beef jerky, snack sticks) Pharmaceutical and medical products Coins and collectables
Food storage
Food safety
In an oxygen-depleted environment, anaerobic bacteria can proliferate, potentially causing food-safety issues. Some pathogens of concern in vacuum packed foods are spore-forming non-proteolytic Clostridium botulinum, Yersinia enterocolitica, and Listeria monocytogenes. Vacuum packing is often used in combination with other food processing techniques, such as retorting or refrigeration, to inhibit the growth of anaerobic organisms.
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