Resumen

RIVERA P., Fernando H. et al. Determinación Microbiológica y Molecular de Listeria sp. y Listeria monocytogenes en Cerdas a nivel de una planta beneficiadora en EUA. Rev. Cient. (Maracaibo) [online]. 2006, vol.16, n.3, pp.297-307. ISSN 0798-2259.

Listeria spp. and Listeria monocytogenes presence in a cull sows processor plant in USA, was evaluated by and PCR multiplex method. 160 cull sows were surveyed after slaughter. Samples were collected from sub-iliac node, iliocecal node, cecal content and carcass swabs. Additionally samples were taken from environment plant and from raw meat ready to be processed. A total of 708 samples were processed. Using traditional microbiology method were found 5.2% of samples positive to Listeria spp. and 0.14% to L. monocytogenes. With PCR multiplex 4.1% were positive to Listeria spp. and 0.85% to L. monocytogenes. There was not significant difference (P ³ 0.05) in the results obtained with PCR multiplex and traditional microbiology procedures. In relation with the raw material that leaves the slaughter area to be processed inside the same plant, Listeria spp. was observed in 1.9% swabs carcass, and 5% of raw sow meat sampled. Listeria spp. was identified in 6.3% and L. monocytogenes in 1.3% of subiliac nodes. It was not any iliocecal node positive to Listeria. Samples supposedly related with the infection source in the process plant, cecal content sample were 19% positive to Listeria spp. and 2.5% to L. monocytogenes. Environmental samples were 4.2% positive to Listeria spp. There were not differences between the conventional microbiology procedure and PCR multiplex technique for this pathogen when carcass swabs and ilicecal node were evaluated with both techniques. Differences were observed between the samples from cecal content and sub-iliac node P = 0.0168 < 0.05 and P = 0.0038 < 0.05 respectively. With the PCR multiplex technique, results were obtained in 8 hours after the second enrichment culture period of the each sample. With traditional microbiological it took 8 days. The incorporation of molecular methodology in the verification process for microbiological controls in the food industry, would allow an important improvement of the effectiveness and dynamics in the food safety systems implanted at the food industries.

Palabras clave : Cull sows; Listeria spp., L. monocytogenes; PCR multiplex; food safety; HACCP.