The process of treating and handling food to prevent or slow down its spoilage caused by microorganisms is called food preservation and the substances used in this process are called preservatives. Sometimes microorganisms such as; benign bacteria, yeast or fungi is added to a food to enhance its quality or to preserve it. For example, a lactic acid bacterium is used to preserve cheese and yeasts are used in production of alcohol.
Preservatives not only inhibit the growth of bacteria, fungi, and other micro-organisms, but also retard the oxidation of fats which cause rancidity. The preservatives also inhibit the natural ageing and discoloration of food such as the enzymatic browning reaction in apples which causes browning when apples are cut.
Sterilizing the equipments, sanitization and sealing of food products in packets are used to keep microorganisms out of food and to reduce the contamination during the food processing. Microorganisms may be removed from liquid foods by filtering and sedimenting them or just by washing and trimming them. Washing is particularly valuable for vegetables and fruits, and trimming is useful for meat and poultry products.
Some common food preservation techniques are:
- Drying, curing and conserving
- Vacuum and oxygen free modified atmosphere packaging
- Carbon dioxide enriched and/or modified atmosphere packaging
- Addition of weak acids such as sodium lactate
- Lactic fermentation
- Sugar preservation
- Ethanol preservation
- Addition of preservatives such as nitrite or sulphite ions
- Food irradiation
- Application of high hydrostatic pressure
- Pulsed electric field processing
In harmonization with the guidelines issued by CODEX and WHO, the FSSAI has laid down regulations for the use of preservatives. As per FSS (Food Products Standards & Food Additives) Regulations, 2011, the preservatives have been classified into Class I and Class II based on their inherent properties & usages.
It is mandatory for the food business operator to declare preservatives on the label of a packaged food product in the list of ingredients. FBOs also required to send the food articles for testing to validate the claims regarding the ingredients made on the label.