Table of Contents
- Food Preservation – Physical Methods
- Summary
- What’s Next?
In the previous segment of the chapter ‘Microorganisms’, we learnt about Food poisoning and chemical methods of food preservation. In this segment, let us get ourselves introduced to the Physical methods of food preservation.
What are the physical methods of food preservation?
Chemical methods for preserving food will not be appropriate for consumables like fruits, vegetables, milk, etc. Thus, well-designed physical methods of preservation are required for such food items. Some of the physical methods of preserving food are as follows:
- Chilling – It is an efficient treatment for the preservation of food items like fruits, vegetables, etc. Microbes are sensitive to extreme temperatures. Thus, low temperature arrests their growth and the food items are not damaged by the microbial activities.
- Boiling – It is a treatment in which the food is heated or boiled to save it from the microbial action. The high temperature kills the microbes present in the food items.
- Smoking – In this method, the food items are not heated directly. They are treated with the release of smoke by burning any organic substance. Food items like meat and fish are subjected to Smoke Drying. The smoke and heat penetrate the microbial cells, thereby destroying them and increasing the shelf life of the food items.
- Canning – It is a method of sealing the processed food items in air-tight containers. This technique helps in increasing the shelf life of food.
- Pasteurisation – It involves the treatment of milk to extreme high temperatures and then immediately to extreme low temperatures. In the dairy unit, milk is passed through huge pipes which are in the form of coils. The milk is treated to around \[ 70^{\circ} Celsius\] for only fifteen to thirty seconds and immediately the temperature is dropped down to \[ 10^{\circ} Celsius\]. The heated temperatures kill the microbes whereas the chilling temperatures prevent the growth of the remaining ones.
