STARTER CULTURES

Starter cultures are food grade microorganisms, which upon culturing in milk or milk based mixes, impart desirable and predictable characteristics of flavour and textures attributable to a certain fermented milk product. The microorganisms coming under the group starter culture may consist of lactic acid bacteria (LAB), propionibacteria, surface ripening bacteria and yeasts and moulds.

These microorganisms have multifunctional role in the fermentation sector of the dairy industry. The rapidity with which the starter cultures produce lactic acid, helps in curd separation from whey during the cheese making process, modifies the texture of the cheeses and fermented milks, and improves preservation. Production of compounds such as diacetyl, acetoin and 2,3 butylene glycol, which are low in molecular weight, adds to the flavour and aroma of the fermented products.

In some special varieties of cheese, such as Swiss cheese, gas production is used for eye formation, which is regarded as desirable. The enzymes originating from the bacterial and fungal cultures add to the flavour development and texture changes during ripening of cheese.

Starter cultures may be classified depending on their temperature of growth as follows.

1. Mesophilic bacteria – they require optimal growth temperatures between 20 – 30°C.

2. Thermophilic bacteria - they require optimal growth temperatures between 40 – 45°C.

Names of certain starter bacteria, their old and new names

Know more about IMPORTANT CHARACTERISTICS OF COMMON LACTIC ACID BACTERIA