Aplication of PCR and RTi-PCR to detect Salmonella spp. and L.monocytogenes in RTE meat products
The efficiency of the detection of Salmonella spp. y L. monocytogenes by RTi-PCR in fuet meat samples treated or not treated by high hydrostatic pressure were assayed versus conventional PCR and conventional microbiological methods. Multiplex detection combined with different pretreatments were assayed. The detecton limit depending on pretreatment was between 102 cfu/ml and 105 cfu/ml.
Investigation and quantification of Salmonella and L.monocytogenes in dry sausages
Con este trabajo se pretende comprobar la presencia de dos patógenos de especial relevancia en salud pública, Salmonella spp. y Listeria monocytogenes en longanizas oreadas. Igualmente se analiza la presencia y concentración de Listeria spp. como indicador-suministrador de la evidencia de que el sustrato reúne las condiciones idóneas de crecimiento y desarrollo de Listeria monocytogenes.
PCR and RT-PCR methods for E.coli O157:H7 and toxigenic organisms' detection in meat products
For rapid detection of E. coli O157:H7 in meat products, a PCR method has been developed. Several selective and no selective enrichment procedures, times of enrichment (0, 2, 4 and 6 hours), DNA extraction methods, with and without inmunomagnetic separation (Dynabeads anti-E. coli O157:H7), and PCR protocols were evaluated. The select prolocol of pre-PCR treatment and conditions of PCR allowed the detection of low numbers of E. coli O157:H7 without enrichment (< 10 ufc/g). This optimized method have been assayed with others artificially inoculated food samples including dry-cured fermented sausages(“salchichón”) and bacon, to evaluate the effect of food matrix on template preparation. The detection limit in salchichón and bacon is lower than 10 ufc/g after enrichment for 2 and 4 hours repectively.
Sampling methods and prevalence of Listeria monocytogenes in meat industries
Twenty one sampling methods to recover L. monocytogenes from environmental surfaces were evaluated to determine the best technique for sampling in the food industry. The best result was obtained with miniroll of nylon. This and other four methods has been used to evaluate incidence of L. monocytogenes in the meat industries.
Incidence of Aeromonas in meat and meat products
Incidence of Aeromonas in fresh meat of rabbit, sheep and goat was tested. No Aeromonas was found in sheep and goat meat. However, 45% of the rabbit fresh meat tested contained Aeromonas. The main strains detected were A. hydrophila, A. caviae and A. sobria. Most of the isolated strains showed haemolytic activity (60%), while 50% showed elactolitic activity. Furthermore, incidence of Aeromonas in faeces of foodborne pattiens from Hospital were investigated. A. hydrophila, A. caviae and A. veronii were found. Some correlation between pulsed field electrophoresis profiles of the strains isolated from rabbit meat and from foodborne pattiens were found.
Detection of enteric viruses in meat products
Several methods to extract RNA to be used in Real time PCR to detect Hepatitis A viruses and norovirus have been developed. Those methods that include silice particles are effectives in the RNA extraction of the above viruses to be used in real time PCR.
