Influence of cryoprotectants on the viability and acidifying activity of frozen and freeze-dried cells of the novel starter strain Lactococcus lactisssp lactis CECT 5180

Lactococcus lactis ssp. lactis CECT 5180 is a novel starter strain with hig hly desirable technological properties, selected to be used a starter cultu re for the manufacture of Afuega'l Pitu cheese, a farmhouse cheese very pop ular in Asturias (Northern Spain). In order to optimise biomass preservatio n of this strain the effect of different substances on the viability and ac idifying activity of preserved cells (by freezing or freeze-drying) was eva luated. On the whole, supplementing reconstituted skimmed milk with certain substances enhances its own highly-protective effect, to different degrees depending on the compound used. In fact, substances as p-alanine for freez e-drying procedures and sugars, glutamic acid or meat extract (only at -80 degreesC) for freezing purposes, showed a highly suitability for preservati on processes, not only as high-survival providers but also in relation to t he reduction in the lag phase of cultures in milk.