From the Department of Microbiology, Medical Science Faculty, Tarbiat Modarres University, Tehran
Abstract: (4291 Views)
71 samples of milk and dairy products were collected from 18 cities throughout
Iran. 93 strains of lactic acid bacteria (LAB) were isolated and assayed against four
opportunistic patho gens including E. coli, proteus and klebsiella as gram-negative
and S. aureus as a gram-positive organism. All indicators (organisms) were
hospital strains. Among isolated bacteria, lactobacilli (37 isolates) had stronger
activity against gram-negative pathogens. 37 isolates were lactococci out of which
9 strains were leuconostocs and seven strains were S.jaecalis. S. aureus was more
sensitive to lactococci than lactobacilli. Only one isolate of leuconostoc inhibited
the growth of gram-negative indicators, but five isolates inhibited S. aureus. The
use of bacteriocin-producing lactic acid bacteria in dairy products provides a
natural mean of preservation.