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

  Lactococcus lactis ssp. lactis CECT 5180 is a novel starter strain with highly desirable technological properties, selected to be used a starter culture for the manufacture of Afuega'l Pitu cheese, a farmhouse cheese very popular in Asturias (Northern Spain). In order to optimise biomass preservation of this strain the effect of different substances on the viability and acidifying activity of preserved cells (by freezing or freeze-drying) was evaluated. 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 β-alanine for freeze-drying procedures and sugars, glutamic acid or meat extract (only at –80  °C) for freezing purposes, showed a highly suitability for preservation processes, not only as high-survival providers but also in relation to the reduction in the lag phase of cultures in milk. Received: 17 January 2000