It is defined as an undesirable changes that occur in food due to the influence of factors like heat, light, air and moisture which favors the growth of various micro-organisms. Foods take different period of time to lose their natural form their spoilage [61–63]. The time for which a food can be kept fresh is called shelf life.

Food preservation is defined as a science which deals with the process of preservation of decay or spoilage of food to be stored in a fit condition for future use. It has been described as a state in which any food may be retained over a long period of time without being contaminated by pathogenic organisms or chemicals and losing optimum qualities of color, texture, flavor, and nutritive value. Preservation is important as it destroys pathogens and reduces the microbial, takes care of the excess produce, adds variety to our meals, and allows food items to be sent to places where they are not grown.

Germs are the major sources which infects food and water. The flies carry germs, they pass on these germs when they sit on our food and spoil it and that is when the food becomes infected. There are different factors that are responsible for food spoilage that are as follows: