Microbial growth can cause undesirable food changes

Microbes have the ability to multiply at high rates when favorable conditions are present.  Microorganism can make both desirable and undesirable changes of the quality of foods, depending on whether they are introduced as an essential part of the food preservation process or arise adventitiously and subsequently grow to produce food spoilage.

Some of these changes, like those taking place during fermentation, are desirable while others, like those resulting in food spoilage and food poisoning are undesirable.

Microbial growth in foods results in food spoilage with the development of undesirable sensory characteristics and in certain cases the food may become unsafe for consumption.

The growth of spoilage microorganisms in foods may result in changes in sensory properties, such as color, odor, texture and appearance.

Undesirable changes can be further subdivided into:
*Those that cause food spoilage, not usually associated with human disease
*Those that cause food poisoning whether or not the food undergoes observable changes
Microbial growth can cause undesirable food changes