The science of microbiology in food
Microscopic organisms in food could be a single cell, multiple cell or have no cells at all. Microorganisms play an important role in our surroundings as all humans, plants and animals contain these organisms. Since microorganisms can survive extreme temperatures they can contaminate foods products and can become harmful if they multiply in large numbers and enter the human body through foods. They are responsible for foodborne diseases like typhoid, amoebiasis, botulism, cholera, dysentery etc. Testing of foods so that microbiological organisms are well within the permissible levels is required as per regulations.
(source: Food Safety Helpline)