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VARIATION OF LAG TIME AND SPECIFIC GROWTH RATE AMONG 11 STRAINS OF SALMONELLA INOCULATED ONTO STERILE GROUND CHICKEN BREAST BURGERS AND INCUBATED AT 25C 1
Author(s) -
OSCAR THOMAS P.
Publication year - 2000
Publication title -
journal of food safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 43
eISSN - 1745-4565
pISSN - 0149-6085
DOI - 10.1111/j.1745-4565.2000.tb00301.x
Subject(s) - salmonella , lag time , inoculation , biology , time lag , lag , variation (astronomy) , microbiology and biotechnology , biological system , bacteria , horticulture , computer science , genetics , physics , computer network , astrophysics
One strain of 11 serotypes or 11 strains of Salmonella, which were isolated from the ceca of broilers, were surveyed for their growth kinetics on sterile ground chicken breast burgers incubated at 25C to determine the variation of lag time and specific growth rate. Growth curves, four per strain, were fit to a two‐phase linear model to determine lag time (h) and specific growth rate (log 10 /h). Repeatability of growth kinetics measurements for individual strains had a mean coefficient of variation of 11.7% for lag time (range: 5.8 to 17.3%) and a mean coefficient of variation of 6.7% for specific growth rate (range: 2.7 to 13.3%). Lag time among strains ranged from 2.2 to 3.1 h with a mean of 2.8 h for all strains, whereas specific growth rate among strains ranged from 0.3 to 0.38 log 10 per h with a mean of 0.35 log 10 per h for all strains. One‐way analysis of variance indicated that lag time (P = 0.029 ) and specific growth rate (P = 0.025 ) differed slightly among strains. S. Haardt had a shorter (P < 0.05) lag time than S. Agona and S. Brandenburg, whereas the specific growth rate of S. Enteritidis was less than (P < 0.05 ) the specific growth rates of S. Typhimurium and S. Brandenburg. All other strains had similar lag times and specific growth rates. The coefficient of variation among strains was 9.4% for lag time and 5.7% for specific growth rate. These results indicate that there were only minor differences in the lag times and specific growth rates among the strains of Salmonella surveyed. Thus, the growth kinetic values obtained with one strain of Salmonella may be useful for predicting the growth of other strains of Salmonella for which data do not currently exist.