Lactic acid bacteria are the most commonly used microorganisms for the fermentation and preservation of foods. However some lactic acid bacteria can cause food spoilage as well.
Homofermentative LAB produce lactic acid, which can be responsible for a sour taste. Heterofermentative LAB form compounds commonly associated with spoilage.
These procedures enumerate/provide the most probable number (MPN) result to indicate the amount of lactic acid bacteria present in a sample.