Evaluation of buffered peptone water (BPW) containing sodium thioglycolate as enrichment broth in combination with BPW as pre- enrichment broth for isolation of Salmonella from radish sprouts

The buffered peptone water (BPW) containing 0.5% sodium thioglycolate (BPWST) as enrichment broth in combination with BPW as pre-enrichment broth for strains of Salmonella from radish sprouts was evaluated. False-positive colonies were found on CHROMagar Salmonella agar used as an isolation medium in 28 out of 30 radish sprout samples (93%) on incubation using BPW, while such colonies were found in 3 samples (17%) using BPWST. The growth of non-starved and starved Salmonella strains in BPWST was found to range from 10 5 10 7 CFU/ml, while non-starved Pseudomonas which produces false-positive colonies was markedly inhibited, at <100 CFU/ml. All starved inoculated Salmonella strains were recovered from radish sprouts, and they were detected in small numbers on starved Salmonella inoculation using both BPW as pre-enrichment and BPWST as enrichment (BPW-BPWST method). The use of the BPW-BPWST method is effective for the isolation of Salmonella from radish sprouts. It is thought that the findings obtained from this study can be applied for the isolation of Salmonella from environments and various hydroponically cultivated raw vegetables.