Physical Method of Food Preservation

The different physical methods of food preservation are given below:

Freezing

This is the modern version of food preservation. This process does not kill the bacteria and yeast, but slows down the spoilage in the food. As yeast and bacteria both grow rapidly at a specific temperature (40F-140F), but lowering the temperature below 40F their reproductive and metabolic actions slow down. Food items such as sliced vegetables, berries, carrots, peas, and many more are preserved by this method.

Drying / Dehyhdration

It is an ancient method used for food preservation. In this, food items are dried decreasing the number of water and as a result, it stops bacterial growth. The drying process can be done by shelf dryers, household ovens, fluidized bed dryers, freeze-drying, spray drying, and commercial food dehydrators. In this method of food preservation, the weight of food products becomes lighter which makes products transportable. Food items such as fruits, vegetables, mushrooms, meats, and many more are preserved by this method.

Salting

It is the oldest method used for food preservation. In this method, salt removes the moisture from food and make an unfavorable environment for micro-organisms. There are very few bacteria that survive this excess high salt condition. This method can be used with other methods (dehydration, acidic solution) too. Food items such as vegetables, some fruits, fish, meats, and many more are preserved by this method.

Canning

This method became popular with the industrial revolution. In this method, food is preserved by removing the oxygen that is a basic need of micro-organisms. But still, some organisms can grow in absence of oxygen, so this method can be used with other methods (salting or with acid). Food items such as jams, juices, vegetables, fruits, and many more are preserved by this method.

Fermentation

This method is done under anaerobic conditions which involve a chemical change in food that use organic acids to convert micro-organisms. These anaerobic conditions occur in the absence of oxygen. This environment stimulates a microbial conversion of starches and sugars into alcohol, which is already a natural preservative. Food items such as cheese, yogurt, and many more can be preserved by this method.

Vacuum Packing

This is done by food vacuum machines. In this method, food items are packed in a bag and then removed all the air present in that bag, and then seal it tight. This method increases the shelf life of food items. Food items such as cereals, nuts, cheese, coffee, and many more can be preserved by this method.

Ionizing Radiation

Irradiation is used for eliminating parasites, reducing pathogenic bacteria, and extending the shelf life cycle of food items. In this method, food undergoes the exposal of ionizing energy which suppresses microbial growth. Food items such as fruits, vegetables, spices, and many more can be preserved by this method.

Food preservation can be defined as the process to slow or stop food spoilage, its loss of nutritional value, quantity, and the edibility of food items. Food preservation methods are divided into two types – physical and chemical. Food preservation by preservatives is another way to preserve food. Let’s discuss food preservation methods and their importance here.