Food preservation can be defined as the science that deals with the process of prevention of decay or spoilage of food thus, allowing it to be stored in a fit condition for future use.
In other words, food preservation is the process in which the perishable food materials are given a suitable physical or chemical treatment to prevent their wastage or spoilage and to retain their nutritive value for long periods.
Microorganisms are responsible for causing or accelerating spoilage but also in some cases, use of benign bacteria and yeasts add specific qualities and preserve food e.g. cheese, wine. Spoilage results in loss of quality, edibility or nutritive value of food. Preservation usually involves the process of treating and handling food to stop or greatly slow down spoilage as well as maintaining or creating nutritional value, texture and flavour of food.
Preservation mainly prevents the growth of bacteria, fungi, and other microorganisms. It also includes processes to check the oxidation of fats which causes "Rancidification"rancidity and to inhibit natural ageing and discolouration due to enzymatic browning. In some cases, preservation also includes sealing of food materials after heat treatment to avoid recontamination with microbes, such as canning. Methods like drying, allow food to be stored without any special control for long periods.
A number of preservation methods include drying, spray drying, freeze drying, freezing, vacuum-packing, canning, food irradiation, and adding preservatives or inert "Gas"gases such as carbon dioxide. Other methods that not only help to preserve food, but also add flavour, include pickling, salting, smoking, preserving in sugar syrup and curing.
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