CHARACTERIZATION AND SELECTION OF DAIRY LACTOCOCCI BASED ON STATISTICAL-ANALYSES OF BIOCHEMICAL AND TECHNOLOGICAL PROPERTIES

A total of 18 dairy lactococcal strains isolated from commercial start ers, curds and fresh cheeses were screened for 63 biochemical and tech nological characters and compared to three reference strains. Using hi erarchical clustering analyses, all these strains were compared on the basis of eight biochemical criteria or seven technological criteria. The technological characteristics under study were growth kinetics, ac idification, diacetyl production and protelysis during growth in milk, as well as 3 peptidase activities. Clusters obtained from these class ifications mainly differed in the proteolytic character of the strains . Principal Component Analyses (PCA) were also carried out on the resu lts of the technological characterization. This statistical method all ows to compare simultaneously all the strains and their technological properties. The two statistical methods used made it possible to evalu ate the relationships between strains on the one hand and between stra ins and their technological properties on the other hand. This study a llowed to select strains for their abilities to acidify milk or to pro duce diacetyl which could be of great interest for the fresh cultured dairy industry. (C) Inra/Elsevier, Paris.