Food preservation involves the process that ensures the safe handling of food for future consumption by preventing its decay. It aims to enhance the shelf-life of food for use when in limited supply by preventing or slowing decomposition.
Causes of food spoilage
Food spoilage is the deterioration of food quality. Factors that cause food spoilage include:
- Mechanical factors
- Enzymes and chemical reactions
- Increase or decrease in moisture content
- Non-enzymatic reactions
- Changes in temperatures
- Microbial activity
- Animals, insects, birds
- Physical damage
Principles of food preservation
- To prevent or deter the decomposition of food by inactivating enzymes or through the usage of chemical reactions. This is usually achieved by methods such as blanching (a food technique where food is immersed in boiling water for several minutes before immediate cooling), which destroys enzymes.
- To reduce the damage caused by animals i.e. rodents, birds, insects etc. or mechanical factors. To deter animals, and insects, from damaging food, the use of pesticides can be used. Proper packaging material also ensures that food is not damaged by these organisms.
- To delay or prevent microbial damage. This can be achieved through processes such as filtration, asepsis, dehydration, refrigeration etc. Asepsis is the process of preventing micro-organisms from food through the use of some sort of covering around a food. This covering acts as a barrier that prevents microbial entry, for example, outer shell or peelings of fruits or nuts. Likewise, a food package can be compared to a covering as it also prevents entry of micro-organisms into a food. The process of filtration involves passing of liquid foods through filters (made of suitable material like porcelain, asbestos, etc) to remove micro-organisms from foods. Processes such as sedimentation, centrifugation, etc can also be used.
Methods of Food Preservation
There are a variety of methods applied to ensure food preservation. They include:
- Drying
- Freezing
- Application of chemicals
- Radiation
- Canning
- Heating
- Salting
- Pickling
In our next posts, we will discuss each of the methods of food preservation comprehensively.