Natural Whey Starter Research Articles

Microbiological and Technological Characteristics of Natural Whey Cultures for Argentinian Hard-Cheese Production

Samples (29) of natural whey starters used in the Santa Fe (Argentina) area for hard cheese production were examined. The microbial composition (including lactic microflora identification) and technological characteristics (acidifying and proteolytic activities) were determined.The cultures consisted mainly of thermophilic lactic acid bacteria belonging to the genus Lactobacillus. L. helveticus (66% the total strains) and L. delbrueckii subsp. lactis (33%) were the dominant species. In every sample, yeasts appeared as the only natural contaminants, at variable contents.The samples showed high acidity levels (1.2 to 1.4% lactic acid) with a mean pH value of 3.3. The acidifying and proteolytic activities were high at temperatures ranging from 37 to 50°C and negligible at 55°C.

Acidification Activity of Thermophilic Lactobacilli Under the Temperature Gradient of Grana Cheese Making

We have studied the growth and acidification activities of strains of the most important species present in natural whey starters for Grana cheese under a temperature gradient that was similar to that used in the first 24h of cheese making. Results showed that strains can be classified according to their ability to adapt to cheese-making conditions. Some strains that had good acidification activity at optimal temperature were not able to decrease pH under technological conditions of cheese manufacture.