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Chapter 14
Starter Cultures and
Bacteriophages
introduction
“Starter culture” is a generic term and has changed its meaning over the years. Currently, it
means a selected strain of food-grade microorganisms of known and stable metabolic activities
and other characteristics that is used to produce fermented foods of desirable appearance, body,
texture, and flavor. Some starter cultures are also used to produce food additives, such as probiotics, and for drug delivery. Toward the end of the 19th century, the term meant inoculating a small
amount of fermented (sour) cream or milk (starter) to fresh cream or milk to start fermentation
in the production of butter and cheese, respectively. 1 This process was found to result in better
products than those produced through natural fermentation of the raw materials. These starters
were mixtures of unknown bacteria. Processing plants started maintaining a good starter by daily
transfer (mother starter) and produced product inoculum from these. However, the bacteriological makeup of these starters (types and proportion of the desirable as well as undesirable bacteria)
during successive transfers was continually susceptible to changes as a result of strain dominance
among those present initially as well as from the contaminants introduced during handling. This
created difficulties in producing products of consistent quality and resulted in product failure
as a result of bacteriophage attack on the starter bacteria. Some private companies started supplying mixed cultures of unknown bacterial composition for cheese manufacture both in the
United States and in Europe. Subsequently, the individual strains were purified and examined for
their characteristics, and starter cultures with pure strains were produced by these commercial
companies. Initially, such starter cultures were developed to produce cheeses. Currently, starter
cultures for many types of fermented dairy products, fermented meat products, some fermented
vegetables, fermented baking products, alcohol fermentation, and other purposes (especially with
genetically modified organisms, GMOs) are commercially available. In this chapter, a brief discussion of the history, current status, bacteriophage problems, and production of concentrated
cultures is presented.
Chapter 14
Starter Cultures and
Bacteriophages
introduction
“Starter culture” is a generic term and has changed its meaning over the years. Currently, it
means a selected strain of food-grade microorganisms of known and stable metabolic activities
and other characteristics that is used to produce fermented foods of desirable appearance, body,
texture, and flavor. Some starter cultures are also used to produce food additives, such as probiotics, and for drug delivery. Toward the end of the 19th century, the term meant inoculating a small
amount of fermented (sour) cream or milk (starter) to fresh cream or milk to start fermentation
in the production of butter and cheese, respectively. 1 This process was found to result in better
products than those produced through natural fermentation of the raw materials. These starters
were mixtures of unknown bacteria. Processing plants started maintaining a good starter by daily
transfer (mother starter) and produced product inoculum from these. However, the bacteriological makeup of these starters (types and proportion of the desirable as well as undesirable bacteria)
during successive transfers was continually susceptible to changes as a result of strain dominance
among those present initially as well as from the contaminants introduced during handling. This
created difficulties in producing products of consistent quality and resulted in product failure
as a result of bacteriophage attack on the starter bacteria. Some private companies started supplying mixed cultures of unknown bacterial composition for cheese manufacture both in the
United States and in Europe. Subsequently, the individual strains were purified and examined for
their characteristics, and starter cultures with pure strains were produced by these commercial
companies. Initially, such starter cultures were developed to produce cheeses. Currently, starter
cultures for many types of fermented dairy products, fermented meat products, some fermented
vegetables, fermented baking products, alcohol fermentation, and other purposes (especially with
genetically modified organisms, GMOs) are commercially available. In this chapter, a brief discussion of the history, current status, bacteriophage problems, and production of concentrated
cultures is presented.