How Does Canning Prevent Food Spoilage

Last Updated on November 9, 2020 by cmoarz

how does canning prevent food spoilage
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Nicholas Appert first introduced canning during the 19th century. The French researcher in 1809 developed a method through which one can preserve food items. It was a means to supply food to the French armies and naval fleet, which would last longer.

Suppose you are wondering, “How does canning prevent food spoilage?” then you are not the first person to ask that. The process involves boiling the food item in a can. Heating the can to a certain temperature kills the microorganisms that find their way into the food.

You can use any container that you can seal for canning. The objective is to have airtight storage, which will prevent harmful bacteria and contaminants from entering. Apart from metal cans, you can even use glass jars, aluminum foils, and plastic pouches for this process. We can even find packaged milk in cartons that are sterilized and sealed.

As long as you seal these containers, they have a longer shelf period. They do not spoil even at room temperature.

Process of Canning

When we think of canning, we think that all we need is stuff the food items into a can and seal the lid. However, this is far from the truth because it involves a lot of steps.

Depending on the type of food we process, we use different methods and follow various procedures. Here are three methods which we use to safely can the food. By thoroughly understanding them, we will be able to answer the question, “How does canning prevent food spoilage?”

Water Bath Canning

Boiling Water Bath Canning is used for processing food with a pH level of 4.6 or lesser. You can preserve high acidic foods using this method. Apple, peaches, cranberries, cherries, pears, tomatoes, jams, butter, marmalades, etc. are some food items you can bottle safely using the Water Bath Canning method.

For this method, you must put the food item inside a jar. The container is then loosely sealed and submersed into a pot. You can then heat it to 100°C (212° F).

Depending on the recipe, the duration would last from ten to twenty minutes. The time taken to boil the can should increase as the altitude rises. 

If the processing time is less than five minutes, then you would need to sterilize the jar. Also, keep in mind to avoid putting a cold jar inside the boiling water. You wouldn’t want the jar to explode or crack open due to thermal shock.

How does the Water Bath Canning method Prevent Food Spoilage?

  • Canning kills the harmful disease-causing microorganisms that may be on the food. It also terminates infectious agents like salmonella, fungi, Escherichia coli O157: H7, and listeria monocytogenes making the food safe for consumption and preventing it from spoiling.
  • By boiling the jar, you can remove any extra air in the container, preventing it from spoiling the food.
  • As the air inside the jar shoots out, it creates a vacuum inside the bottle. The air pressure around the container becomes greater than the force that the air exerts from the inside. Thanks to this, the can is sealed properly. Also known as the hermetic seal, this prevents the air from entering.
  • While preserving food items like pickles, the Water Bath Canning method helps the acid like vinegar to sip into the food. Heat processing makes it easy for the acid to enter into the low-acid ingredient and preserve it. 

Atmospheric Steam Canning Method

The effectiveness of the Atmospheric Steam Canning Method has been a burning issue for many years. It was only recently that researchers agreed that this method could be effective in processing acidic food. To process food with a pH level less or equal to 4.6, you use Steam Canners.

The basic principle of the Water Bath Canning and Atmospheric Steam Canning method is the same and uses heat to sterilize the jar. Instead of submerging the jar in the water, the only difference is that the latter uses steam from a reservoir to heat the can placed right above it. If done properly, it is as effective as the water bath canning.

How does Steam Canning method Prevent Food Spoilage?

  • The steam provides enough heat to kill off pathogenic microbes that could spoil the food and harm the body.
  • If the air cooling process is done right, it kills most microbes that might infect the food.
  • The heat from the steam removes the jar’s air; it creates a vacuum sealing the jar.

Pressure Canner       

A pressure canner is a method that involves placing the jar of food in a pressurized container. The specially made pressure cooker is filled with three to four inches of water and heated. The temperature it achieves is 240°F. This level of heat is achieved only due to the pressure that the storage chamber creates.

The pressure varies from 10-11 pounds at sea level depending on whether you use weighted or dial gauge pressure canner.  

How does the Pressure Canning method Prevent Food Spoilage?

  • As they can reach a temperature of 240°F, they are used to preserve low-acid foods. You can also use it to preserve food ranging from meat, vegetables, and even seafood.
  • Low acid food carries the chances of causing botulism, which the bacterium Clostridium botulinum causes. The normal canning process cannot kill it. Only by using pressure canning, you can make sure that your food is safe from these pathogens.

Precautionary steps 

  • Choose a canning method based on the food item you want to process. Each ingredient reacts differently, so it needs to go through a varied process. The recipes for preserving them will vary.  
  • Be aware of the altitude where you live. You will have to make certain adjustments to the heat and pressure treatment based on the height.
  • Wash the equipment, including the ingredients and jars, thoroughly before you begin the canning process.
  • Never can food items that are already rotten.
  • Ensure that there are no cracks on the jar or the lid.


By now, you must have got some idea to the question, “How does canning prevent food spoilage?” Canning is an efficient way to preserve our favorite food items. It is a cheap and easy method which you can carry out without wasting much time. Choosing the right ingredient and recipe is key to secure a successful canning process. 

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