IAFP 2009 Program Book and Abstract Book - AB145

The number of samples showing more than 105 CFU/g of ACC was 1 out of 32 (3.1%). Coliforms were detected in 21 samples out of 32(65.6%). Low heating temperature at the final cooking stage, and holding dishes for more than 2 hours at room temperature before reheating, were associated with contamination level of B. cereus (P 50 CFU/g. These were evaluated using the FDA-BAM method and the PCR method with five replicates per level per food type. One food type, cheese, was tested for naturally occurring fungi with 30 replicates of which 10 were positive for detectable fungi. Results: For inclusivity testing, all 222 fungal isolates tested were found to be reactive, while the 30 bacterial strains all were non-reactive with the PCR method. For effectiveness testing, when evaluated as positive or negative at the threshold level of 10 CFU/g, results with the PCR method on all three artificially inoculated sample types were statistically indistinguishable from the reference method. For naturally contaminated cheese evaluated at a threshold level of 50 CFU/g, results with the PCR method were also statistically indistinguishable from those with the reference method. Significance: The PCR assay was able to give plus/minus results for fungi within 48 h, providing a significant time saving which can lead to faster release of product, more useful shelf-life, and a less complicated supply chain. P2-112 Microbiological Quality of Water Samples from Hidalgo, Queretaro and Mexico State MIROSLAVA SANCHEZ MENDOZA, M. Elizabeth Castelazo-Padilla, Verónica Hernández-Cervantes, M. Elena Gil-Recasens, M. Dolores Ramirez-Hernández and Mireya Albores Bernal Lab State of Public Health, Pachuca, South Introduction: In Mexico, the health authority has a surveillance program for monitoring sources of water supply such as springs, wells and service network, as well as purified bottled water, to evaluate its quality. Purpose: Analyze the microbiological quality of purified water and water for human consumption in the states of Queretaro, Hidalgo and Mexico. Methods: In the period January to December 2008, 18,089 samples of water (6,125 tap water, 3004 well, 79 spring, and 8881 purified water), were analyzed for microbiological and chemical test. The determinations made were presence of aerobic mesophilic bacteria, total coliform organisms and/or fecal, as well as detection of Escherichia coli or Vibrio spp. The techniques used were established in the Mexican Official Standards. Results: Microbiological analysis showed that of 9,475, 3,261 (22.3%) were off standard. Water from the spring showed the highest percentage of samples outside the norm (59.46). While the chemical determinations of 35,215, 8.75% were off standard. The state with the highest number of results that were off standard was the state of Mexico, with 59.37%, followed by Hidalgo with 38.55% and Queretaro with 2.09%; the latter is also the state with the fewest samples analyzed. Significance: The results show that even when there are basic sanitation programs established, the health authorities must put more attention on chlorination practices of water network and wells, as well as strengthen health promotion activities to the population, to prevent the presence of gastrointestinal or viral diseases caused by water consumption. P2-113 Simultaneous Separation and Detection of Multiple Foodborne Pathogens Using Magnetic Nanobeads and Quantum Dots HONG WANG, Michael F. Slavik and Yanbin Li University of Arkansas, Poultry Science, Fayetteville, AR, USA Introduction: Three species of foodborne pathogenic bacteria, Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Typhimurium, were the major foodborne pathogens associated with poultry, meat and vegetable products. Current conventional detection methods are still limited by their time-consuming process, non-specific or nonquantitative results, complex procedures, or high cost. Purpose: The objective of this study was to develop a rapid, sensitive and selective method for simutaneous and quantitative detection of three major pathogens in food products using magnetic nanobeads to separate and concentrate the target bacteria and quantum dots as fluorescent labels in a biosensing method. Methods: Multi-target bacteria were separated simultaneously from samples by using magnetic nanobeads (30 nm) which were coated with specific antibodies. QDs with different emission wavelengths (525 nm, 605 nm, and 705 nm) were conjugated to anti-Salmonella, anti-Listeria, and anti-E. coli O157 antibodies, respectively. The nanobead-bacterial cell complexes reacted with QDs-antibody conjugates to form bead-cell-QDs complexes. The intensities of fluorescence emission peaks at 525 nm, 605 nm, and 705 nm of the final complexes were measured for quantitative detection of S. Typhimurium, L. monocytogenes, and E. coli O157:H7 simultaneously. Results: Results indicated that this method could detect E. coli O157:H7, S. Typhimurium, and L. monocytogenes at a concentration as low as 10 to 50 CFU/ml in food samples. Linear relationships were found between the fluorescence intensity and each of the three pathogens. The total detection time including sampling and measurement was less than Abstract Book — 145 Poster

IAFP 2009 Program Book and Abstract Book

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