Gone are the days of when human could gather what they needed for the day. However, with the onset of agricultural production, farmers were faced with a challenge of making sure the harvest lasts until the next and they had to devise a way of preserving food. This is how food preservation came into existence.
Food preservation prevents the growth of microorganisms (such as yeasts), or other microorganisms as well as slows the oxidation of fats that cause rancidity. Food preservation has become an increasingly important component of the food industry. But with preservation comes food spoilage in the picture which can be attributed to one of two major causes: the attack by pathogens(disease causing microorganisms) such as bacteria and molds, or oxidation that causes the destruction of essential biochemical compounds and/or the destruction of plant and animal cells.
Food preservation helps in:
1. Increasing the shelf-life of foods thus increasing the supply. So many perishable foods can be preserved for a long time.
2. Making the seasonal food available throughout the year.
3. Decreasing wastage of food by preventing decay or spoilage of food.
4. Improving the nutrition of the population. Preserved foods help people to bring a variety in the diet, thereby decreasing nutritional inadequacies.
Let's take an example of milk. Why do we boil milk? So that we can use it for a longer time. You know boiling delays milk from getting sour. Let's have a look at 4 preservation techniques which have been used so far
The rate of deterioration slows down when a food is frozen. Fresh fruits and vegetables, when harvested, continue to undergo chemical changes which can cause spoilage and deterioration of the product. Vegetables must therefore be blanched in boiling water first to destroy enzymes and microorganisms to limit enzyme activity while frozen.
The term "thermal" refers to processes involving heat. Heating food is an effective way of preserving it because the great majority of harmful pathogens are killed at temperatures that is at boiling point of water. Boiled preserves must be sealed in airless conditions (e.g. airtight jars) to prolong their shelf life.
3. Moisture Removal
Microorganisms need moisture to grow, and die off in dry conditions. Therefore, food can be dried using warm air or an oven, or sealed in a concentrated solution of salt or sugar that draws out moisture by osmosis.
Most pickling is carried out in a acidic solution such as vinegar, saltwater solution called as brine solution. The primary advantage of pickling is food preservation; pickling prevents spoilage and greatly extends shelf life. Pickling as food preservation was particularly important in agricultural societies before household refrigeration.