Starter and Ancillary Cultures

Carla Orsi1 and Angelo V. Zambrini2

  • 1 Department of Research & Development, Granarolo S.p.A., Bologna, Italy
  • 2 Department of Quality, Innovation, Safety, Environment, Granarolo S.p.A., Bologna, Italy

Introduction

Starter cultures are cultures of selected microorganisms that are deliberately added to milk to initiate and carry out dairy fermentations under controlled conditions (Ustunol, 2015). Starter cultures play an essential role in manufacturing fermented dairy products and therefore are of great industrial significance. Most starter cultures used today have their origin with lactic acid bacteria, which have been used in the production of fermented dairy products for over 4,000 years. Industrial lactic starter cultures were first introduced in the second half of the nineteenth century for the manufacture of cheese and butter in North America. Initially, they were liquid cultures in sterilized glass bottles that required a few transfers before becoming the bulk starter culture. They were prepared from natural starter cultures used by cheese factories having a history of excellence and success in making good cheese from raw milk. Early commercial starter cultures consisted of a mixture of mesophilic lactococci and leuconostoc, eventually purified, grown in pasteurized skim milk and maintained as stable multistrain cultures (Cogan et al., 2007).

It was in the late 1930s that dry culture were made available, but the first freeze-dried cultures appeared only in the middle of the 1950s. The first cryogenically frozen mother culture was made available commercially in 1965, and the highly concentrated version for direct setting of cultured milk appeared 10 years later.

Today, the dairy industry makes wide use of these highly stable and active concentrated starter cultures, either deep frozen or freeze-dried. Thanks to these cultures, most of the dairies have eliminated the need for internal starter preparation—operation that required several days, dedicated equipments, and skillful personnel to achieve the desired activity and eliminate the risk of contamination.

 
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