Potential Salmonella transmission from ornamental fountains.

Besides the usual food and drinking-water vehicles, there are other routes by which Salmonella can be transmitted, especially at outdoor locations. Public fountains containing Salmonella offer models of exposure routes beyond those usually considered in the context of recreational use. The authors studied the bacteriological quality of water sampled from five ornamental fountains in Guadalajara, Mexico during two periods of six and of 10 months. Coliform bacteria and Escherichia coli were detected in 75 percent and 49 percent of the samples, respectively, and various serovars of Salmonella enterica were found in 12.4 percent of samples. In addition to risks from ingestion of the contaminated waters; ornamental fountains may also pose risks to people in the vicinity from inhalation of mists.

Fate of Salmonella in Salpicon, a Mexican Cold Shredded Beef Salad.

The fate of Salmonella during the preparation and storage of salpicon, a cold shredded beef salad commonly consumed in Mexico, was evaluated. Salmonella contamination was introduced by a person shredding the cooked beef, who previously had handled raw pork containing several native serotypes of Salmonella at 9,000 salmonellae per g. The salad was prepared with 0, 2, or 4% vinegar and was held for 48 h (8 at 24-26°C and 40 at 5-7°C). The optimal concentration of vinegar for acceptable salad flavor was 4%. The initial number of salmonellae in salads prepared with 0 or 4% vinegar was 20/g. Salmonella populations increased to 5,000 after 48 h. Salmonella did not grow in salad containing 4% vinegar (pH 5.3); however, the organism was isolated at levels of 7 cells per g at 48 h of incubation. Fourteen different serovars of Salmonella were isolated from the salads. Critical control points in the preparation and storage of salpicon are shredding the beef, the concentration of vinegar, and rapid cooling of salad before serving.