CHARACTERIZATION OF THE LACTIC ACID BACTERIA IN EWE?S MILK AND ARTISANAL CHEESE FROM NORTHWEST ARGENTINE

MEDINA, R.B.; KATZ, M.; GONZÁLEZ, S.N.; OLIVER, G.

JOURNAL OF FOOD PROTECTION

IAFP

Año: 2001 vol. 64 p. 559 - 563

0362-028X

Indigenous lactic acid bacteria in ewe?s milk and artisanal cheese was studied in four samples of fresh raw milks and four one-month-old cheeses from the province of northwest Argentina. Mean growth counts on M17, MRS and MSE agar media did not show significant differences (p< 0.05) in raw milk and cheeses. Isolates of lactic acid bacteria from milk were identified as Enterococcus  (48%), lactococci (14%), leuconostocs (8%) and lactobacilli (30%). All lactococci were identified as Lactococcus lactis (subsp.lactis and subsp. cremoris). Lactobacilli were identified .as Lactobacillus plantarum (92%) and Lactobacillus acidophilus (8%). Form cheeses were isolated enterococci (59%) and lactobacilli (41%). Lactobacillus plantarum (93%), Lactobacillus acidophilus (5%) and Lactobacillus casei (2%) were most frequently isolated. Lactococcus lactis subsp. lactis biovar diacetylactis strains were considered as fast acid producers. Lactococcus lactis subs. cremoris strains were slow acid producers. Lactobacillus plantarum and Lactobacillus casei strains identified from the cheeses showed slow acid production. The majority of the lactobacilli and Lactococcus lactis strains utilized citrate and produce diacetyl and acetoin in milk. Enzyme activities (API-ZYM tests) of lactococci were low, but activities of Lactobacillus plantarum strains were considerably higher. The predominance of Lactobacillus plantarum in our artisanal cheese are probably important in the ripening of these cheeses due to their physiological and biochemical characteristics