Identification and technological characterization of lactic acid bacteria isolated

OLISZEWSKI, RUBÉN; VAN NIEUWENHOVE, CARINA; GONZÁLEZ, SILVIA; PÉREZ CHAIA, ADRIANA

Revista Argentina de Tecnología

Centro de Publicaciones de la Universidad nacional

Lugar: Santa Fe; Año: 2006

The characteristics of  102 strains isolated from goat milk, curd and cheese were studied. They were identified as lactobacilli (60%), enterococci (35%) and pediococci (5%). The species isolated were L. plantarum, L. rhamnosus, L. delbrueckii subsp. bulgaricus, L. fermentum, E. faecium, and P. pentosaceus. Technological characteristics showed that only 5% of strains coagulated milk in less than 15 h, 25% between 24-48 h, 30% between 48-72 h and 40% were never capable of coagulating milk. The diaceyl/acetoin production showed that 15% of the isolate had a high production corresponding to the 66% of L. rhamnosus and 71% of E. faecium isolated. The acidifying capacity, showed a low pH values in L. delbrueckii subsp. bulgaricus, L. rhamnosus and P. pentosaceus (between 4.50 and 4.66 of pH) and high values in the other species (between 4.85 and 5.09). Tritratable acidity values obtained were high in L. delbrueckii subsp. bulgaricus, L. fermentum and P. pentosaceus (between 67 and 74°D); medium in L. rhamnosus and  L. plantarum (between 56.6 and 59.5°D), and low in E. faecium (46.3°D). All the species showed citrate degradation, with a high proportion in L. fermentum and L. delbrueckii subsp. bulgaricus. Growth in fast-slow differentiation agar showed positive results in more than 50% species in all genera. Seventeen strains with the best performance in diverse technological aspects were selected to be evaluated by the semi-quantitative API-ZYM system. Keywords: Lactic acid bacteria; Raw milk; Goat; Technological characteristics