The occurrence of salmonellae in bean sprouts in Thailand

Detection of Salmonella spp. in 344 samples of bean sprouts was attempted by pre-enriched in buffered peptone water (BPW) or lactose broth (LB) at 37 degrees C, followed by selective enrichments, selenite cystein broth (SCB) and Rappaport medium (RV) at 43 degrees C. Four selective media, bismuth sulphite agar (BSA), brilliant green agar (BGA), Salmonella-Shigella agar (SSA) and MacConkey agar (MA) were used for isolation. Salmonellae were isolated from 30 (8.7%) samples. They were serotypes lexington (56.7%), orion (16.7%), senftenberg (16.7%), tennessee (3.3%), poona (3.3%) and weltevreden (3.3%). Pre-enrichment in LB, followed by enrichment in SCB and streaking on to BSA gave the highest recoveries. Fifteen of 30 strains isolated were sensitive to all 14 antibiotics tested. Seven strains were resistant to one, and a strains showed multiple resistance to 2-4 antimicrobial agents.