Starter Cultures

 Starter cultures are those microorganisms that are used in the production of cultured dairy products such as yogurt and cheese. The natural microflora of the milk is either inefficient, uncontrollable, and unpredictable, or is destroyed altogether by the heat treatments given to the milk. A starter culture can provide particular characteristics in a more controlled and predictable fermentation. The primary function of lactic starters is the production of lactic acid from lactose. Other functions of starter cultures may include the following:

  • flavour, aroma, and alcohol production
  • proteolytic and lipolytic activities
  • inhibition of undesirable organisms

There are two groups of lactic starter cultures:

  1. simple or defined: single strain, or more than one in which the number is known
  2. mixed or compound: more than one strain each providing its own specific characteristics

Starter cultures may be categorized as mesophilic, for example:

  • Lactococcus lactis subsp. cremoris
  • L. delbrueckii subsp. lactis
  • L. lactis subsp. lactis biovar diacetylactis
  • Leuconostoc mesenteroides subsp. cremoris 

or thermophilic:

  • Streptococcus salivarius subsp. thermophilus (S.thermophilus)
  • Lactobacillus delbrueckii subsp. bulgaricus
  • L. delbrueckii subsp. lactis
  • L. casei
  • L. helveticus
  • L. plantarum

Mixtures of mesophilic and thermophilic microorganisms can also be used as in the production of some cheeses.

Please see further details in our cheese technology section.