Incidence of salmonellae in duck eggs in Thailand.

Detection of salmonellae was performed on egg shells and egg contents of duck eggs. Five hundred and sixty-four tested samples were came from 1,128 eggs, 2 eggs in each sample. Eggs were collected from retail markets in Bangkok, Chon Buri, Chachoengsao, Lop Buri, Ang Thong and Nakhon Ratchasima provinces during January through June 1992. The percentage of salmonellae contamination on the egg shells only, egg contents only and both shells and contents were 12.4%, 11% and 0.2%, respectively. Twenty three serotypes were identified from the 133 salmonellae isolates. The common serotypes found from duck eggs were Salmonella typhimurium, S. cerro, S. tennessee, S. amsterdam, S. agona and S. infantis accounting for 5.5%, 4.1%, 2.8%, 2.1%, 1.4% and 1.1%, respectively.

Detection of salmonellae in hen eggs in Thailand.

Two thousand four hundred and ninety eggs were collected from retail markets in 6 provinces and from laying hen farms in 3 provinces. Eggs were pooled in groups of 3 to obtain 830 samples for testing. Isolation of salmonellae was made from both egg shell and egg contents. Eggs from retail markets were contaminated with salmonellae on egg shells (13.2%) and in egg contents (3.9%). Three (0.4%) samples yield positive both on egg shells and in egg contents. Of the 86 samples from laying hen farms, salmonellae were found on egg shells and in egg contents, 3.5% and 1.2%, respectively. From the 134 strains tested, twenty-four serotypes were confirmed. Salmonella cerro, S. amsterdam and S. typhimurium were predominantly encountered, 4.8%, 4.3% and 1.4%, respectively. Only two samples were contaminated with S. enteritidis, one each from open market and laying hen farm, one on egg shells and the other in egg content respectively.

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.