Food Preservation With Vacuum - How & Why It Works

Food Preservation With Vacuum - How & Why It Works

August 31, 2021

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by Katy Manning

Food preservation is an important part of our lives. The capability to keep food from spoiling for longer has practical benefits, including reducing food waste. In the recent past, vacuum packing has emerged as one of the most popular packing methods in domestic and commercial spheres.

Denis Papin first demonstrated the use of a vacuum to preserve food in the 17th century. In his experiment, he used an air pump to create a vacuum to preserve food. However, it was only after the introduction of vacuum-packed meat in the 1920s that vacuum packing went mainstream.

 

What Is Vacuum Packing Food Preservation?


Vacuum packing is a food preservation technique that involves removing air from the pack before sealing the product in the low-oxygen permeability pack. The vacuum pump pulls air out of the pack, ensuring the packing material remains in close contact with the food item. Doing this negates the formation of any air pockets between the food item and the packing material.

Most commercially available vacuum packaging machines for domestic use have a nozzle vacuum pump to draw out air and create a vacuum. Other types of vacuum pumps in use include B Chamber-Type vacuum packaging machines, C Skin-Type vacuum packaging machines, and the D Deep-Draw Type vacuum packaging machine.

In most cases, the packing material is flexible and capable of contouring against the food item. However, there are instances where the packing material is rigid. In this regard, the type of packing material does not matter as long as it can create a sealed vacuum around the food item.

Consequently, the vacuum pump in conjunction with the sealed pack helps maintain an oxygen-deficient environment. The anaerobic environment prevents the growth and proliferation of spoilage bacteria and fungi, thereby increasing the shelf life of the food item while maintaining high quality.

 

Why Does Vacuum Packing Preserve Food?

 

The underpinning goal of vacuum packing is to create an anaerobic environment. Removing oxygen from direct contact with the food item has two benefits:

#1. It prevents oxygen from reacting with the food item, which deteriorates its quality and appearance. A good example of this effect is the oxidative rancidity of fats which require oxygen to take place. Additionally, color changes in food are almost always caused by oxygen.

#2. It prevents the growth of spoilage bacteria. Vacuum packing food items prevents bacteria from growing, which, in turn, reduces spoilage of perishable food (foods that require cold storage and are not stable at room temperature for long). Spoilage bacteria are the various bacteria that spoil food in the ways humans can perceive through odor, color, and appearance.

Such bacteria need oxygen to survive and spoil food in ways you can perceive with your senses. Creating an anaerobic environment deprives the food of the necessary oxygen they need to multiply. This slows down the deterioration of food quality.

While preventing the growth of spoilage bacteria goes a long way to increase the longevity of food items, there is still a risk of other types of bacteria multiplying and making your food unsafe for consumption. The resulting anaerobic environment is the perfect breeding ground for anaerobic bacteria such as C. botulinum which causes botulinum poisoning.

C. botulinum grows at room temperature in moist, low acid, and oxygen-deprived environments. Moreover, the lack of competition from the spoilage bacteria gives the anaerobic bacteria the perfect environment to reproduce more readily and faster.

With the above in mind, removing oxygen from the food’s storage environment will prevent spoilage bacteria from growing, but it increases the risk of anaerobic bacteria infesting perishable food. This problem does not arise in non-perishable foods such as dried nuts, crackers, and dried spices.

To prevent anaerobic bacteria from growing, you should freeze the vacuum-packed food items. Lowering the temperature negates the pathogenic activity of anaerobic bacteria. Ideally, you should not keep vacuum-sealed food items at temperatures above 40 degrees Fahrenheit for more than 2 hours in total.

 

How Long Will Vacuum Sealed Food Last?

 

The vast majority of vacuum-packed food items will last 1 or 2 weeks in your refrigerator, which is 2 to 4 times longer than the standard shelf life of perishable food. Typically, perishable food will last 1 to 3 days when stored conventionally.  

Storing the vacuum-packed food items in a freezer increases its storage period significantly. For instance, vacuum-packed fish, vegetables, fruits, poultry, and meat can last from 1 to 3 years when stored in a freezer.

 

Benefits Of Vacuum Sealing Food Preservation

 

Obviously, the main benefit of vacuum-sealing foods is to preserve food quality for longer. You can store your food far longer when you use vacuum packing than other traditional preservation methods. However, there are numerous other benefits you accrue from vacuum packing. These include:

  • Eliminate Oxidation – As explained above, vacuum packing gets rid of oxygen or diminishes the amount of oxygen your food is exposed to, therefore, preserving the quality of food for longer, its color, and odor.
  • Maintain The Food’s Natural Moisture Content – Exposure to the environment causes the food to lose moisture. Vacuum packing protects your food from drying out by preserving its natural moisture.
  • Preserve Oils And Flavor – Vacuum packing helps preserve the delicate flavors and natural oil much the same as it preserves natural moisture. Preserving natural oil is especially important for food containing omega-3 fatty acids such as fish.
  • Prevents Freezer Burn – Freezer burns are common for foods frozen without preparation. The burns occur when the surface of the food dehydrates, causing the food to be dry and attain a leathery appearance. Vacuuming packing food protects the foods from cold, dry air.
  • Preserve Food Structure – For instance, vacuum-packed stored vegetables will have noticeably better structure and texture than foods stored out in the open. Given that the food items retain their moisture and oils, they will inevitably retain their natural structure, hence feel better to eat.


What Foods Are Vacuum Packed?

 

There are numerous food items you can vacuum pack and refrigerate for longer shelf life. Such food items include vegetables, fruits, cured meats, fish, ground coffee, cereals, nuts, cheese, pasta, and much more.

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