NATURAL MILK CULTURES FOR THE PRODUCTION OF ARGENTINEAN CHEESES

Samples (32) of natural milk cultures used in the Santa Fe, Argentina, area for soft and semihard cheese production were examined. The micro bial composition (including lactic acid microflora characterization) a nd technological parameters (acidifying and proteolytic activities) we re evaluated. The cultures contained mainly thermophilic lactic acid b acteria, identified as Streptococcus salivarius subsp. thermophilus (9 6.8% of the total strains) and Enterococcus spp. The strains showed a low proteolytic activity. The isolates of S. salivarius subsp. thermop hilus exhibited a widespread phage resistance. The nonlactic microflor a comprised coliforms, yeasts, spore-forming bacteria and lactate ferm entative bacteria. The samples showed an acidity level from 0.38 to 0. 69% lactic acid (pH from 4.25 to 5.75). The acidifying activity was op timal at 45 degrees C. The advantages and disadvantages of the employm ent of natural milk starters are discussed.