Food preservation is the treatment of food to stop or reduce spoilage, loss of nutrients and loss of quality. It has been a common practice since ancient times. Preservation usually inhibits the growth of microorganisms which are the main cause of food decay. It has developed over a long time from the primitive to modern methods and is classified into two categories namely: traditional and modern methods.
Traditional methods includes drying and smoking.
Sun drying which is an ancient method of food preservation reduces the amount of moisture in the food hence preventing the growth of bacteria. This method is used for preservation of grains such as maize, wheat, beans etc.
Smoking is another older method which is used in preserving food such as meat and fish. Some vegetables, fruits and ingredients like tea and malt, which are used for making drinks, are also preserved using this method.
Salting is another method that dates back to ancient times and was used mainly for preservation of red meats. Salt which is composed of sodium chloride dehydrates the food through the process of osmosis. The growth of microorganisms in dehydrated food is inhibited hence the food can stay for a long period of time without getting spoilt.
Honey has been in use since ancient times for preservation. It is has been established that honey itself can stay for a long period of time without getting spoilt. A piece of meat smeared with honey cannot go bad easily.
Refrigeration preserves the food by inhibiting the growth of microorganisms. Refrigeration is used in preserving a wide variety of food like fruits, vegetables, fish, milk etc.
Freezing is used in homes and business premises for preserving wide variety of food. With this method food is exposed to low temperatures and the growth of bacteria and fungi is greatly reduced. Freezing is also used to preserve bulk food in the cold rooms. This method of food preservation is suitable for storing food for emergencies.
Vacuum packing is the storage of food in the airtight containers. The process removes atmospheric oxygen thus limiting the growth of microorganisms. Also this method is useful for preventing of evaporation of volatile components in the food. This method is suitable for long term preservation of dry foods such as cereal, nuts, cured meat, cheese, potato crisps, smoked fish and coffee. It can also be used to store fresh foods on a short term basis.
Use of artificial food additives is another method of food preservation. It involves the use of chemical preservatives. This method inhibits the growth of bacteria and fungi. Chemical preservatives contain anti-oxidant which absorbs the oxygen and prevent the oxidation of food constituents. Preservatives commonly used are: sodium nitrate, sodium propionate, sodium nitrite, sulfites, formaldehyde and disodium EDTA.
I discourage using any method of preservation that calls for chemicals. Consumption of these preservatives, especially formaldehyde is extremely toxic and foreign to your body’s system.
Pickling is a method of food preservation in which food is mixed with edible anti-microbial liquid. This liquid serves as a microorganism inhibiting agent. Pickling is categorized into two methods, chemical pickling and fermentation pickling. In chemical pickling food is put into the anti-microbial liquid that inhibits microorganisms from spoiling the food. Agents used in pickling include; brine, vinegar, alcohol and vegetable oil. Boiling is done to make sure that pickling agent saturates the food. Foods that are pickled in this method include cucumbers, peppers, vegetables, corned beef etc. The food itself produces pickling agent in fermentation pickling.
Another method is the use of sodium hydroxide that makes the food too alkaline for the growth of bacteria.
Canning is the cooking of food and sealing it in sterilized cans. The cans are then exposed to heat to kill the remaining bacteria. This method is used in preservation of canned food such as meat, fruits, fried beans etc. Learn to Can! Learn a new skill this year with this how-to video and online tutorial.
Irradiation is a method of food preservation in which food is exposed to high energy electromagnetic radiation such as x-rays or gamma rays. This kills the microorganisms and also reduces spoiling of fruits. High dosages of radiation may render the food harmful.
High pressure food preservation is used to prevent the growth of microorganisms. The food is stored under high pressure. This method can be used to preserve juice and meat.
Use of hurdle technology, which eliminates the pathogen present in the food by scientific approach, is the most recent method of food preservation. Consider the best and most convenient method for you to preserve your large amount of food long term. Master more than one method and come back and share your ideas and recipes.