chapter  20
Fermented Milks
Pages 22

The fermenting of milk is a fairly simple, cheap, and safe way to preserve milk. In regions with high-quality milking and milk collection system, a high level of technological know-how to preserve raw milk, and good transportation and distribution facilities, the need for fermentation as a preservation method does not exist. In regions where such facilities are lacking, the fermenting of milk as a means of preservation has kept its original importance. The lactic acid bacteria alter the conditions in the milk in such a way that most undesirable organisms, including pathogens, cannot grow or even die. These conditions include a low pH (4.6-4.0), which also helps in maintaining a low pH in the stomach after consuming the milk; growth inhibition by undissociated acids (e.g., lactic acid) and by other metabolites such as H20 2 and compounds with an antibiotic activity; a low redox potential; consumption by the lactic acid bacteria of compounds that are vital for the growth of other organisms. Appropriate pasteurization of the raw milk kills any pathogens that may survive the fermentation.