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

Type Old Name New Name Where used?
Mesophilic
O
Streptococcus lactis,
Streptococcus cremoris
Lactococcus lactis subspecies lactis
Lactococcus lactis subspecies cremoris
Cheddar cheese, Feta
cheese, Cottage cheese,
Quarg, Curd or Dahi,
Lassi, Shrikhand
L S.lactis
S.cremoris
Leuconostoc citrovorum Leuconostoc lactis
Lactococcus lactis subspecies lactis
Lactococcus lactis subspecies cremoris
Leuconostoc mesetenteroides ssp cremoris
Leuconostoc mesetenteroides ssp lactis
Continental cheese,
Cultured butter,
Feta cheese
D S.lactis
S.cremoris
S.diacetylactis
Lactococcus lactis subspecies lactis
Lactococcus lactis subspecies cremoris
Lactococcus lactis subspecies lactis biovar diacetylactis

Cultured Butter
LD S.lactis
S.cremoris
S.diacetylactis

Leuconostoc citrovorum Leuconostoc lactis
Lactococcus lactis subspecies lactis
Lactococcus lactis subspecies cremoris
Lactococcus lactis subspecies lactis biovar diacetylactis
Leuconostoc mesetenteroides ssp cremoris
Leuconostoc mesetenteroides ssp lactis
Continental cheese,
Mould ripened cheese,
Cultured butter milk,
Cultured Butter

Thermophilic Streptococcus themophilus
Lactobacillus bulgaricus
Lactobacillus helveticus
Lactobacillus lactis
Streptococcus salivarius ssp thermophilus
Lactobacillus delbrueckii ssp bulgaricus
Lactobacillus delbrueckii ssp helveticus
Lactobacillus delbrueckii ssp lactis
Yoghurt,
Dahi,
Mozzarella cheese, Grana cheese

Know more about IMPORTANT CHARACTERISTICS OF COMMON LACTIC ACID BACTERIA