Review on lactic acid bacteria function in milk fermentation and preservation

This review was conducted to find out the main function of lactic acid bacteria in milk fermentation and preservation. Lactic acid bacteria (LAB) are a group of Gram-positive, non-spore forming, cocci or rods, which produce lactic acid as the major end product during the fermentation of carbohydrates. LAB includes Lactobacillus, Lactococus, Streptococcus and Leuconostoc species. The presence of LAB in milk fermentation can be either as spontaneous or inoculated starter cultures. Both of them are promising cultures to be explored in fermented milk manufacture. LAB has a role in milk fermentation to produce acid which is important as preservative agents and generating flavour of the products. The main reasons for the fermentation practice using LAB are to increase milk palatability and improve the quality of milk by increasing the availability of proteins and vitamins. Furthermore, LAB confers preservative and detoxifying effects on milk as well. When it is used regularly, LAB fermented milks boost the immune system and strengthen the body in the fight against pathogenic bacterial infections. Thus, LAB fermentation is not only of a major economic importance, but it also promotes human health. Therefore, it was concluded that the lactic acid bacteria have a vital role in milk and milk products fermentation and preservation and this suggests the need for educating the communities about benefits of consuming fermented milk and milk products needs to be part of health education.   Key words: Fermentation, lactic acid bacteria, milk, preservation.