Food Protection Trends - February 2010 - 98

Rationale and Objectives: the present study was designed to measure the effectiveness of the Listeria Isolation transwab, a self-contained swab-based test kit that can be used on site, and to compare its performance with two traditional reference methods (UsDa and Iso). the Listeria Isolation transwab (LIt) includes a dry swab, together with a tube of straw coloured gel medium. the swab is rubbed across a test surface, inserted into the gel and incubated at 37°C for 24–48 hours. Blackening of the medium indicates a positive result due to aesculin hydrolysis. Both the reference methods require primary and secondary enrichment stages in the laboratory before a final result is obtained. For this study, a number of organisms known to hydrolyse aseculin were used. suspensions of each organisms at different dilutions were used to inoculate either the LIt, swabs which were tested according to the two reference methods. Results and Findings: LIt showed equivalent sensitivity to the two reference methods for Listeria monocytogenes, with a minimum detection level of 15 CFU per swab. other Listeria species were also detectable at low levels. In contrast false reactions were only detectable for very high levels of other aesculin hydrolysers, such as Enterobacter aerogenes (over 43000 CFU). Conclusions: From the study, LIt appears to be capable of alerting users to the presence of low levels of Listeria monocytogenes. P1-27 Prevalence of Salmonella spp. in Porcine and Bovine Raw Meat and By-products in Southern Germany C. MeyeR, s. thiel and a. stolle, LMU-Munich, Faculty of Veterinary Medicine, Institute of Food Hygiene, Schoenleutnerstr. 8, 85764 Oberschleißheim, Germany Introduction: salmonellosis is, after campylobacteriosis the second main cause of bacterial human enteritis in Germany. Salmonella spp. is known to colonize the gastrointestinal tract of animals without producing any clinical or pathologic-anatomic signs. therefore, carcasses of asymptomatic animals can be contaminated with Salmonella spp. at the time of slaughter. Contaminated raw or undercooked meat is considered an important factor in transmitting this foodborne pathogen. thus, this study was undertaken to contribute to the understanding of the actual risk potential of raw meat and by-products originating from pigs and cattle. a further aim was to find out if a seasonality could be observed. Rational: From March 2008 to January 2009, a total of 4172 beef and pork raw meat samples and by-products were tested qualitatively for Salmonella spp. using the VIDas system. Positive samples were confirmed by isolation of the agent with cultural methods. the samples, composed of 1368 beef and 2804 pork samples, were obtained from seven different slaughterhouses in Southern Germany. Results: the overall prevalence of Salmonella spp. in pork and beef was 1.1% and 0.1%, respectively. the highest contamination rate of porcine samples was found in tongues and livers with 5.0% and 4.5%, respectively. the prevalence of Salmonella spp. in pork carcasses amounted to 1.1%, while no Salmonella spp. could be found in porcine kidneys and lungs. as for the bovine samples, Salmonella spp. were isolated only from tongues at a rate of 2.2%. With the exception of May, June and July, positive porcine samples were detected all over the year, observing a slight seasonal increase in the colder months. From bovine samples Salmonella spp. were isolated only in June. Conclusions: although the Salmonella spp. prevalence found in this study was relatively low compared to previous surveys, the risk of transmitting this pathogen cannot be neglected in terms of preventing foodborne zoonoses. P1-28 Comparison Study to Demonstrate the Equivalence of the SimPlate Total Campylobacter-CI Method to the Reference Culture Method for the Enumeration of Total Campylobacter jejuni and Campylobacter coli in Food Philip t. Feldsine, Mandeep Kaur and andrew H. Lienau, BioControl systems Inc., Bellevue, Wa 98005–4356, Usa Introduction: the simPlate for Campylobacter Color Indicator (C-CI) method allows for the quantitation of total Campylobacter jejuni and Campylobacter coli in poultry meat and poultry meat rinses after 48 to 52 h of incubation in a microaerophilic environment. Purpose: a study was undertaken to compare the simPlate C-CI method to the reference culture method for the quantitation of total Campylobacter jejuni and Campylobacter coli. 98 FOOD PROTECTION TRENDS | FEBRUARY 2010

Food Protection Trends - February 2010

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