Thermophilic lactic acid bacteria phages isolated from Argentinian dairy industries.

SUÁREZ, V.; QUIBERONI, A.; BINETTI, A. G.; REINHEIMER, J. A.

JOURNAL OF FOOD PROTECTION

INT ASSOC FOOD PROTECTION

Año: 2002 vol. 65 p. 1597 - 1604

0362-028X

A total of  61 autochthonal phages (59 of Strep. thermophilus and two of  Lactob. delbrueckii subsp. bulgaricus) were isolated from Argentinian dairy plants since 1994. Specifically, 17 yogurt samples (18 % of total) and 26 cheese samples (79 %) contained phages lytic against STREP.  thermophilus strains. The numbers of viral particles in samples were variable and ranged from 102 to 109 PFU/ml. Phages belonged to Bradley’s group B or the Siphoviridae family (morphotype B1). They showed high burst size values and remarkably short latent periods. The results clearly showed that cheese-making processes are more susceptible to phage attacks that the yogurt ones. A high sensitivity of commercial streptococci strains was demonstrated, while a remarkable resistance was exhibited by autochthonal strains isolated from natural milk cultures. (Key words: bacteriophages, dairy plants, lactic acid bacteria)