Bacterial Cultures
Cultures for cheese making are called lactic acid bacteria (LAB) because their primary source of energy is the lactose in milk and their primary metabolic product is lactic acid. There is a wide variety of bacterial cultures available that provide distinct flavor and textural characteristics to cheeses. For a more detailed description of cheese cultures and microbiology, see Fox (2004), Kosikowski and Mistry (1997), and Law (1997).
Starter cultures are used early in the cheese making process to assist with coagulation by lowering the pH prior to rennet addition. The metabolism of the starter cultures contribute desirable flavor compounds, and help prevent the growth of spoilage organisms and pathogens. Typical starter bacteria include Lactococcus lactis subsp. lactis or cremoris, Streptococcus salivarius subsp. thermophilus, Lactobacillus delbruckii subsp. bulgaricus, and Lactobacillus helveticus.
Adjunct cultures are used to provide or enhance the characteristic flavors and textures of cheese. Common adjunct cultures added during manufacture include Lactobacillus casei and Lactobacillus plantarum for flavor in Cheddar cheese, or the use of Propionibacterium freudenreichii for eye formation in Swiss. Adjunct cultures can also be used as a smear for washing the outside of the formed cheese, such as the use of Brevibacterium linens of gruyere, brick and limburger cheeses.
Yeasts and molds are used in some cheeses to provide the characteristic colors and flavors of some cheese varieties. Torula yeast is used in the smear for the ripening of brick and limberger cheese. Examples of molds include Penicillium camemberti in camembert and brie, and Penicillium roqueforti in blue cheeses.
General Manufacturing Procedure