Food security usually defined as the availability of healthy and enough food for healthy life to all the people in all over the world at all the times at reasonable cost. The history of food preservation for its security is as old as the history of mankind; the best examples are the storage of food by ancient Egypt kings in great famines of the world. The Holy Quran also describes the preservation of food by the prophet Yousaf (A.S) in the famine. But today there is more need of food security due to increasing population. The population of world increases greatly so for constant healthy food supplying to whole world requires its proper preservation and handling.
Food preservation is the process of treating and handling food in such a way as to stop or greatly slow down the spoilage of food and also extends its shelf-life. It involves preventing the growth of micro organisms specially bacteria, fungi (such as yeast), or other microorganisms, as well as slowing the oxidation of fats that cause rancidity in the food. Rancidity produces bad smell in the food and can cause diseases in the consumer which may be any living organism usually human beings.
Over the years many food preservation methods have been improved to increase the shelf-life of foods while minimizing changes to the quality and nutritional content. Most of the people preserve fruits and vegetables by drying and freezing for short period of time. Food can be preserved by using different methods, for example Refrigeration and freezing, canning, Dehydration, Freeze-drying, Pickling, Pasteurizing, Fermentation etc. not only at small scale but also at industrial level. At industrial level these methods are used to store food for longer time periods and mostly for storage to export food materials out of country to get more income and to improve economy of the country, but the basic theme of export is to provide the food to whole world. In this way these methods help in solving the major issue of the world regarding to food which is food security.
All of the food preservation processes work by slowing down the activity and growth of disease causing bacteria, or by killing the bacteria all together. They also slow down or stop the action of enzymes which can degrade the quality of the food. For preserving food we increase the temperature due to which water availability in food and pH of food decreases, due to the decreases of water contents and pH of food we can preserve it for a long time.
There are some methods used for food preservation:
Drying or dehydration of food: Drying is the oldest method for preserving food. Over hundreds year ago people use this method for preservation of meat by sunlight drying. When we dry food we provide temperature to the food as enough as it does not cook it only become dry. Heating of food at specific temperature will kill all the microbes and slow down the growth of microbes. An electric dehydrator is best for drying and dehydrating of food. We can also use oven, by using sun heat but these methods are time consumer and produce low or bad results as compared to dehydrator. Water is necessary for most of chemical reactions run by micro organisms which cause spoilage of food, in the method of dehydration water evaporates by temperature so food become save from spoilage as well as growth of algae and fungi.
Canning is the process of applying heat to the food that sealed in a jar in order to destroy all microorganisms that can cause food spoilage. Proper canning techniques stop this spoilage by heating the food for a specific period of time and killing these unwanted microorganisms. During the canning process, air is driven from the jar and a vacuum is formed as the jar cools and seals.
Although we may hear many of canning methods, but only two are approved by the United States Department of Agriculture (USDA). These are water-bath canning method and pressure canning method:
Water-bath canning: This method sometime referred as hot water canning, uses a larger kettle of boiling water. Filled jars are submerged in the water and heated it for a specific period of time. Use this method for processing high-acid foods, such as fruits, pickled food, and tomatoes.
Pressure canning: Pressure canning uses a large kettle that produces steam in a locked compartment. The filled jars in the kettle heated it for a specific period of time under a specific pressure (stated in pounds) that’s measured with a dial gauge on the pressure-canner cover. Use a pressure canner for processing vegetables and other low-acid foods, such as meat, poultry and fish.
Don’t confuse a pressure canner with pressure cooker, which is used to cook food quickly. A pressure cooker does not have the ability to preserve foods it only has the ability to cook food quickly.
Freezing of food: Freezing of food is the art of preparing, packing and storage of food in the freezer. We can store all type of food e.g. fruits, vegetables, meats, cakes, fish, and breads. When we buy food make sure it is absolutely fresh, store this food in the freezer quickly as possible at the proper frozen temperature. Proper packing and storage of food helps to prevents from any reduction in the quality of food. Sometimes due to the less supply of electricity, overfill of freezer, food become damage but damaged food does not hurt us it only makes the taste of food bad.
Here are three things which help to prevent from the damage of food;
- Don’t overfill the freezer, if we overfill the freezer air circulation reduce and food become damage.
- Wrap the food tightly, due to which air does not circulate in the food.
- Keep the freezer closed as much as possible.
Conclusion: A number of diseases especially diseases of digestive tract spread from unhealthy and improperly stored food in the world. “Care from a disease is more beneficial than its cure”. So there is a need of proper as well as advance methods to preserve food for food security. Because food preservation is the only way to provide healthy food to whole world means to meet the criteria of food security.
B.Sc (Hons) Agri.Sciences