Prevalence of Salmonella sp in foods in Tamaulipas, Mexico, during 2005

Objective. To determine the prevalence of Salmonella sp. in foods obtained from Tamaulipas sanitary jurisdictions during 2005. Materials and methods. Several kinds of foods were taken from the State of Tamaulipas from January to December 2005, which were analyzed in the Public Health State Laboratory of Tamaulipas. If the food fulfilled with the acceptance criteria, it was analyzed looking for Salmonella sp. in agreement with NOM-114-SSA1-1994. Positive foods were sent to the National Institute of Epidemiological Reference and Diagnostic (INDRE) to determine Salmonella species and serovariety. Data were collected in a database and analyzed using chi(2) and Fisher's exact test in STATA 8.2 software. Results. 24 of 1300 analyzed foods were positives to Salmonella sp. (1.9%, CI 95% 1.2 - 2.7). By sanitary jurisdiction, Victoria showed the highest prevalence of positive results (3.9%). When the analysis was carried out by "north jurisdictions" versus "south jurisdictions", south jurisdictions showed a high prevalence of Salmonella in foods (0.9% vs 2.5% p < 0.05). Sausage was the most contaminated food (20.0%). A higher percentage of positive results was noticed in terrestrial foods than in sea-derived foods (2.3% vs 0.3%; p < 0.05). In January (5.5%) and May (3.7%) the highest prevalence of positive results was found; without significant difference by year seasons (p > 0.05). The most common bacterial species was Salmonella enterica, serovariety enteritidis, which was found in 58.3% (n = 14) of positive foods. Conclusions. The jurisdictions with the highest prevalence of Salmonella in foods were identified. Terrestrial foods showed more Salmonella contamination. The results show that thanks to epidemiologic surveillance it is possible to identify potential sources of salmonelosis outbreaks. A bigger research effort it is necessary to extent the epidemiologic surveillance activities and their results, by one side toward the kind of foods initially identified as "high risk foods", and by other side, to other regions of Mexico in order to know the distribution of this pathogen and establish adequate preventive measures.