Incidence of Listeria monocytogenes and evaluation of the sanitary qualityof filleted fresh fish from the Metropolitan Area of San Jose.

Fish constitutes a very important part of human diet due to its protein con tent. The poor commercialization system existing in Costa pica far this pro duct causes on important secondary contamination that may include microorga nisms such as fecal coliforms, Staphylococcus aureus and even pathogens suc h as Listeria monocytogenes. There is a lack of recent information about th e microbiological quality of the fish that arrives to the Metropolitan Area of San Jose, Costa Rica, so the aim of this work was to study it through t he detection of microbiological indicators and the incidence of L. monocyto genes. Five different samplings were realized to 27 fisheries located in two diffe rent areas from San Jose, Costa Rica: the Central Market and the rest of th e Metropolitan Area. Each time, a 500g sample of fresh filleted fish was ta ken and transported to the Food Microbiology Laboratory, Universidad de Cos ta Rica, for performing the different analysis, which included the presence /absence of L. monocytogenes, total plate count, total and fecal coliforms count and Most Probable Number of Staphylococcus aureus. Also, a hygiene ev aluation of the different fisheries was performed. According to this, 22,2% of the fisheries were classified as excellent, 14,8% as good, 40,8% as reg ular and 22,2% as bad. Fisheries hygiene is independent of the incidence of L. monocytogenes with a 95% confidence level, and there is no significant relationship between hy giene and the other indicators analyzed. There is a significant relationshi p between the incidence of Listeria sp. and the hygiene of the Central Mark et area. It was determined that 96,3% and 29,6% of the fisheries accomplish with the microbiological limits established by ICMSF for S. aureus and total plate count, respectively, Listeria sp, was found in 65,2% of the fish samples an alyzed. From these, 52,3% was L. monocytogenes, 43,2% L. innocua, 3,4% L. i vanovii and 1.1% L. seeligeri. In 88,9% of the fisheries the presence of L. monocytogenes was positive at least once.