Molecular Study of the useful and the Contaminant Microflora in Fermented Dairy Products

ABSTRACT

Lactic acid bacteria have been used as starter strains in the production of fermented dairy products for centuries. Most of the dairy products contain lactic acid bacteria, but also other bacteria involved as contaminant microflora. We explored the microbial content of home-made dairy products and those purchased from the market. In our study twenty-six pure cultures were isolated. The isolated strains were investigated by a set of physiological and molecular-genetic methods for their accurate species identification and genotyping. From the microorganisms, involved in fermentation and ripening of dairy products with proven health benefits to human, in studied foods predominated Lactobacillus delbrueckii, Lactobacillus helveticus and Lactobacillus plantarum. Another part of the isolated strains, representatives of the genus Kluyveromyces, Rhodotorula and Candida were contaminant microflora, as a result of poor hygiene in the manufacture and storage of the dairy products. Some of these strains were isolated from commercially available dairy products. The obtained results raise again the question about the efficacy of microbiological quality control and food safety.

Keyword:

• contaminant microflora
• Lactobacillus
• probiotics