Explain the Sources of Microorganisms?

Microorganisms are virtually present everywhere in nature including air, water and soil. The microbial flora is also associated with the food from the time of harvest from the plant or slaughter of an animal till it is used as a food. Foods are biological materials derived from once living organisms and are perishable commodities, i.e., subject to spoilageand decomposition. Spoilage refers to change in the quality of food, in terms of food appearance, texture, flavour, odour and even alteration in nutritional properties. Spoilage leads to biological, chemical and physical changes in food. The major causes of food spoilage are microbial growth and enzymatic and chemical reactions. Besides spoilage causing microorganisms, other microbes of importance are pathogenic microorganisms on food. These organisms, e.g., Staphylococcus, Campylobacter, Clostridium perfringens, E. coli etc. are responsible for outbreaks of food borne infections and food poisoning.