Dairy Lactococci

Abstract

Lactococci are commonly dominant in natural dairy fermentations and in majority components of starter cultures used in large-scale cheese making. Strains of Lactococcus lactis, of both lactis and cremoris subspecies, and the diacetyl-forming biovariety diacetylactis are of industrial significance. The growth of lactococci in milk induces a rapid fall in the pH, prevents the growth of undesirable microorganisms, and provides optimal conditions for ripening. Lactococci are also responsible for the formation of cheese texture and flavor through their proteolytic and amino acid conversion pathways. Physiological and genetic data accumulated over the past 25 years allowed lactococci to be used for the expression of heterologous proteins, the synthesis of food-grade additives and nutraceuticals, and the delivery of vaccines.