Food preservation is the process that prevents food spoilage, food poisoning, and microbial contamination in food. It is one of the methods to protect food from unwanted microbial growth. After the food is produced, we store and protect by covering the rice and curry with lids to keep away flies and other insects. By this, we are protecting it from any infection caused by them. This is a short-term condition. Food preservation, on the other hand, is done to preserve food for a longer time.
Objectives of Food Preservation
Following are the important objectives of food preservation:
- To prevent microbial contamination.
- To kill pathogens.
- To minimize food spoilage and food poisoning.
- Preserve food for future purposes.
Methods of Food Preservation
There are some of the methods of food preservation:
- Chemical Method: Salt and edible oils are two main preservatives that are used for ages to prevent microbial growth. This is why we add extra oil to pickles. Preservation by salt is known as salting. Salting helps to preserve fruits for the long term. Meats and fishes can also be preserved by salting. Other synthetic preservatives include vinegar, sodium benzoate, sodium metabisulphite, etc.
- Sugar: Sugar is another common preservative used in jams and jellies. Sugar is a good moisture absorbent. By reducing moisture content, it restrains microbial growth.
- Heat and Cold Methods: Boiling and refrigeration prevent around 70 percent of microbial growth. Boiling kills the microorganisms that cannot tolerate extreme temperatures. Thus, it helps in food preservation. Refrigerators have very low temperatures. Since microbes do not get the optimum temperature they need for growth, their growth is inhibited.
- Smoking: Smoking prevents dehydration in fish and meat and thus prevents spoilage. The wood smoke contains a large number of anti-microbial compounds that slow the rancidification of animal fats.
- Canning: The food contents are sealed in an airtight container at high temperatures. Meat, fish, fruits are preserved by canning.
- Sterilization: This method is carried out to remove microbes from food. For eg., milk sterilization at 100°C kills the microbes.
- Dehydration: It is the process of removal of water from food. It is the simplest method and prevents food spoilage by removing water.
- Lyophilization: This is the process of freezing and dehydration of the frozen product under a vacuum.
- Radiation: This method is also known as cold sterilization. The UV rays, X rays, gamma rays kill all the unwanted microbes present in food.