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PCR Detection and Microbiological Isolation of Salmonella spp. from Fresh Beef and Cantaloupes
Author(s) -
GallegosRobles M.A.,
MoralesLoredo A.,
ÁlvarezOjeda G.,
OsunaGarcía J.A.,
Martínez I.O.,
MoralesRamos L.H.,
Fratamico P.
Publication year - 2009
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1750-3841.2008.01006.x
Subject(s) - salmonella , isolation (microbiology) , polymerase chain reaction , biology , food science , foodborne pathogen , microbiology and biotechnology , pathogen , inoculation , contamination , food contaminant , bacteria , gene , listeria monocytogenes , ecology , biochemistry , genetics , immunology
ABSTRACT: Species belonging to the genus Salmonella are an important cause of enteric fevers, gastroenteritis, and septicemia, and the pathogens are commonly transmitted through contaminated food. In this study, polymerase chain reaction (PCR) amplification of a 287‐bp region of the invA gene was compared to a microbiological technique to determine the presence of Salmonella in retail beef and in cantaloupe rinse samples. Both methods showed the same level of sensitivity, detecting 1 CFU/25 g of meat after enrichment for 24 h at 42 °C. The presence of Salmonella was determined in 50 commercial top sirloin beef samples that were not artificially inoculated. Three samples were positive by the microbiological method, and these samples and an additional sample were positive by the PCR. Both methods were also used to test surface rinses of cantaloupes collected from 4 farms in Nayarit, Mexico. Salmonella was detected by the microbiological method in 9 of 20 samples (45%), whereas the pathogen was detected by the PCR in 11 samples (55%). This study demonstrates the utility of the PCR targeting the invA gene to determine the presence of Salmonella spp. in beef and cantaloupe samples.