Use of two 16S DNA targeted oligonucleotides as PCR primers for the specific detection of Salmonella in foods

Abstract

A 16S DNA targeted polymerase chain reaction (PCR) method specific for the detection of Salmonella isolates with various serotypes was developed. The primers used for such a PCR method were 16SF1 and 16SIII. 16SF1 is the reverse and complementary strand of 16SI which has been shown to be able to hybridize with Salmonella and Citrobacter spp. 16III on the other hand, is able to hybridize with Klebsiella and Serratia spp. in addition to Salmonella. Although 16SF1 and 16SIII were not specific to Salmonella only, when they were used as PCR primers, only the Salmonella isolates could be specifically detected. The interference from Citrobacter, Klebsiella and Serratia spp. could be prevented. None of the other non-Salmonella isolates including strains of the family of Enterobacteriaceae closely related to Salmonella would generate the false-positive reaction. When this PCR system was used for the detection of Salmonella cells artificially contaminated in food samples, results obtained were satisfactory. A detection limit of N x 10(0) cells per assay could be obtained.