Preservation Of Food And Agricultural Commodities
Food preservation is the science that deals with the process of preventing spoilage or decay of food. Preservation of foods and agricultural commodities allows them to be stored in a fit condition so that they can be used in the future. When food is preserved, it can be retained for a certain period without getting contaminated by chemical or pathogenic organisms. The preserved food or agricultural commodities also do not lose the optimum qualities of texture, flavor, nutritive value and color.
The benefits of food preservation include ensuring that seasonal foods are available throughout the year, adding variety to the diet, stabilizing food prices and decreasing wastage of food. Food preservation can also save time by minimizing the energy and time required to prepare food because it has been partially processed.
One of the effective methods of food preservation is food irradiation. This food safety technique eliminates disease causing microorganisms like E. coli O157:H7, Salmonella and Campylobacter from foods. Irradiation can be used to preserve a wide variety of foods, including meat, poultry, vegetables, fruits and spices. This process is effective and safe in reducing or eliminating harmful bacteria, parasites and insects. In certain vegetables and fruits, irradiation delays ripening and inhibit sprouting.
The effects of irradiation on the foods and agricultural commodities as well as on the humans and animals eating the foods have been extensively studied for more than four decades. The studies clearly show that when irradiation is used on food as approved, its nutritional value remains unchanged and the food does not become radioactive. The process reduces or eliminates disease causing microorganisms.
The process of irradiating food involves exposing it to amounts of ionizing radiation that are carefully controlled for a certain period to achieve various desirable objectives. The sources of radiation, which are approved on foods, include Gamma rays, Electron beams and X-rays.
When the microbes that are present in the food or agricultural commodities are irradiated, the energy from the radiation breaks the bonds present in DNA molecules. This causes defects in the genetic instructions of the microbes. This leads to the death of the organisms or their inability to reproduce.
When food is being irradiated, it matters if it is fresh or frozen. A large radiation dose is required to kill microorganisms in frozen foods. The effectiveness of irradiation also depends on the sensitivity of the microorganism on irradiation, the rate at which it is able to repair damaged DNA and the amount of DNA in the target organism.
Insect pests and parasites that have high amounts of DNA are killed rapidly by low doses of irradiation. More irradiation is required to kill bacteria since it has less DNA. Viruses are generally resistant to irradiation at doses that are approved for foods.
If the food stills contain living cells, they will be killed or damaged just like the microbes are. This effect is useful. It is used to increase the shelf life of vegetables.
Irradiation does not destroy all bacteria. It is not the same as sterilization. The irradiation of food is an important tool in preventing illness and death from food borne diseases, but it cannot act as a substitute for comprehensive food safety programs or good food handling practices. Irradiated foods should be handled, stored and prepared in the same way as foods that are not irradiated.