[Contamination of fish ceviche by Salmonella in Guadalajara++, Jalisco, Mexico]

This study was done to find out the incidence of Salmonella contamination of fish prepared and sold in 89 fixed and mobile food-vending establishments in the city of Guadalajara, Jalisco, Mexico. The pH of the samples analyzed varied between 3.8 and 5.2 (median = 4.55), and their temperature ranged from 9 to 29 degree C. Of the 221 samples studied (20 g each), 16% were positive for Salmonella. The proportions positive in fixed and mobile establishments were, respectively, 12% and 20%. The positive percentages were higher during mild and hot periods than during cold weather. The preenrichment technique proved less efficient for isolating Salmonella than direct enrichment. Salmonella was isolated from two of eight samples with pH below 4.0. The results indicate that eating ceviche may pose a health risk, especially for persons whose resistance to food-transmitted enteropathogens is low. Therefore, it should be emphasized that lime juice does not guarantee the safety of ceviche.