Resumen del Libro
The microbiological profile of the muscle Longissimus dorsi from six bovine of local production was evaluated under two packaging conditions (vacuum packaging and commercial packaging). Samples were packed at refrigeration conditions (2°C) and bacterial growth of aerobe and anaerobes present at 0, 3, 7 and 14 days of storage was also evaluated. Results from statistical analysis showed that there is no significant difference in microbial growth due to type of packaging for it cant be infer that a packaging type is better than other from the microbiological point of view. Identification of several bacteria was conducted through a characterization of bacterial groups. Enteric bacteria growth under aerobic conditions at selective and differential culture media and enteric bacteria O157 growth in chromogenic media were identified. The pathogen Escherichia coli O157:H7 was not found at the samples analyzed. Biochemical tests demonstrated the presence of Peptostreptococcus, Prevotella oralis and Staphylococcus saccharolyticus in vacuum packed samples and the presence of Porphyromonas assacharolytica from commercially packed meat samples. Indistinctly the packaging type used the presence of Pseudomonas spp., Enterococcus spp., Staphylococcus spp., Enterobacter spp. and Escherichia coli were detected with chromogenic media even though their quantity varied depending on the packaging and the bacterial oxygen requirements. Even when it was expected a better microbiological quality of vacuum packed meat, the tests conducted showed that this samples contain anaerobe and facultative microorganisms which can affect eventually the organoleptic properties of meat and general acceptance by deterioration of the product.