RESUMEN
The polymerase chain reaction (PCR) shortens conventional microbiological methods for the detection of food pathogens either by replacing the conventional biochemical and serological identification or by its direct use on pre-enrichment media or food products. PCR allows fast and highly reliable identification of bacterial taxa, particularly phenotypically atypical bacterial strains. For reliablity, PCR primers and reaction conditions must be thoroughly optimized and evaluated, appropriate sample preparations must be developed, and a stringent laboratory protocol must be followed. Positive control systems are used to monitor possible inhibition of the reaction and negative controls are needed to monitor for contamination. The most recent developments involve messenger RNA-based (mRNA-based) detection of viable bacterial pathogens and real-time PCR quantitation of pathogens.
Asunto(s)
Bacterias/genética , Bacterias/aislamiento & purificación , Técnicas Bacteriológicas , Microbiología de Alimentos , Reacción en Cadena de la Polimerasa/métodos , Bacterias/patogenicidad , Técnicas Bacteriológicas/normas , Microbiología de Alimentos/normas , Reacción en Cadena de la Polimerasa/normas , Control de Calidad , ARN Bacteriano/genética , ARN Mensajero/genéticaRESUMEN
The prevelance of Listeria spp. and Listeria monocytogenes in ready-to-eat poultry products was examined. Following 16 or 48 h of enrichment and selective plating, presumptive Listeria colonies were identified using polymerase chain reaction and reverse hybridization on line probe assay strips. Overall, Listeria spp. and Listeria monocytogenes were found in 35.5% and 15.5% of the poultry samples, respectively. The incidence of Listeria spp. was much higher in unpackaged (41.7%) than in prepackaged (11.1%) poultry products.
