A microbiology laboratory deals with the qualitative and quantitative estimations of microorganisms as of interest in a given situation. This interest may be the need to assure the quality of products, safety in handling and consuming them, the probable spoilage they may undergo; or it may be to recognize the effective functioning of microorganisms in processing (fermenting) food.

Products examined microbiologically may be water (potable and for other uses), foods & feeds, and non-food items. The tests performed in a food microbiology testing laboratory are mostly to examine the following parameters or microorganisms, but are not limited to what is given below.

The testing may extend to the following microorganisms in specific situations where food is known to be vulnerable or is exposed to reservoirs of pathogenic microorganisms:

In a given situation the need to examine the microorganisms is judged on the basis of the intrinsic and extrinsic characteristics of the foods that permit preferential growth of certain microorganisms, the processing the food was subjected to, and the historical evidence of exposure to reservoirs of microorganisms. In all microbiological tests, culture techniques are combined with an examination of biochemical color reactions to identify and confirm the presence of microorganisms.