IAFP 2009 Program Book and Abstract Book - AB75

Methods: A total of 34 samples (18 cactus leaves, 8 soil, and 8 water) were taken randomly from the high, middle, and low levels of a nopal production field between May and June of 2006. Traditional microbiological methods (NOM-114SSA1-1994) and PCR were used to determine the prevalence of the pathogen and serotyping, ribotyping, and PFGE were used to further confirm and characterize the isolates. Results: Based on both microbiological and PCR analyses, 23 of 34 total samples (67.4% prevalence; 12 positive samples from nopal leaves, 7 from surrounding soil, and 4 from pond/irrigation water) were positive for Salmonella spp. Serotyping revealed that the isolates were either S. Typhimirium or S. javiana. The results from PFGE of selected isolates (10 from cactus leaves, 3 from soil, and 2 from water) revealed that the isolates displayed 3 pulsotypes. Most isolates (8 of 16 isolates; 2 from water and 6 from nopal leaves) belonged to pulsotype III, whereas pulsotype I contained 6 isolates (4 from nopal leaves and 2 from soil) and pulsotype II contained 2 isolates (both from soil). It was possible to associate strains from nopal leaves with those recovered from water or soil based on pulsotype, but it was not possible to associate isolates from soil with those from water based on PFGE. Significance: These data suggest that nopal may become contaminated with Salmonella from both water and soil and suggests that it may serve as a vehicle for transmission of this pathogen to the public, particularly those at higher risk, who may consume fresh or processed nopal. P1-38 Survival of Salmonella spp. during Preparation of Pancakes and Waffles TIMOTHY W. ANDERSON, Harshavardhan Thippareddi and Korasapati N. Rao University of Nebraska-Lincoln, Food Science and Technology, Lincoln, NE, USA Introduction: Salmonella contamination has been the cause of several food product recalls, including dry pancake and waffle mixes. Purpose: The purpose of this study was to evaluate the survival of Salmonella spp. during pancake and waffle preparation. Methods: The pancake and waffle batters were prepared from two types of mix, original and buttermilk, as per manufacturer’s instructions by adding milk or water, oil and egg. The batter was mixed uniformly to minimize the lumps. The batter was inoculated with a five strain cocktail of Salmonella spp. to obtain ca. 107 CFU/g of the batter. The pancakes were prepared on an adjustable temperature flat griddle, using different time-temperature combinations (250°F for 1.45, 2.00, and 2.15 min; 375°F for 1.15, 1.30 and 1.45 min; 425°F for 0.45, 1.00, and 1.15 min) , while waffles were made in a Belgium style waffle maker using three different settings (3, 4.5 and 6). The surviving Salmonella spp. populations were enumerated on XLD and PCA. Samples with Salmonella spp. populations below the detection limit were subjected to a modified FDA-BAM enrichment procedure. Results: Salmonella spp. populations were reduced to below the minimum detection limit (0.699 CFU/g) when plated on XLD agar during preparation of the pancakes and waffles. Salmonella spp. populations were reduced by 4.6 to 5.6 and 4.3 to 6.0 log CFU/g in pancakes prepared from original mix and buttermilk mix, respectively. The microbial reductions were 6.2 to 6.9 log CFU/g in original mix waffles, and 5.4 to 6.1 log CFU/g in buttermilk mix waffles. Salmonella spp. was detected in almost all samples of pancakes and waffles prepared using various time-temperature combinations. Significance: The pancake and waffle preparation methods were effective in reducing the Salmonella spp. populations. However, Salmonella spp. cells may survive the cooking process and pose a health risk for at-risk individuals. P1-39 Survival of Salmonella spp. during Preparation of Popcorn AIKANSH SINGH, Nageswara R. Korasapati and Harshavardhan Thippareddi University of Nebraska, Food Science and Technology, Lincoln, NE, USA Introduction: Salmonellosis ranks first among the foodborne outbreaks in the United States. The presence of Salmonella on corn has been reported in literature. Purpose: We evaluated the survival of Salmonella spp. during popcorn preparation, using three different popping methods. Methods: The corn obtained from a local grocery store was inoculated with a five strain cocktail of Salmonella spp. to obtain 6.84, 2.70, 0.99 log CFU/kernel. The control as well as inoculated corn were popped using three different methods: microwave, hot air and electric heater following manufacturers’ directions. The surface temperature obtained during the three popping methods was measured using infra red imaging system. The surviving Salmonella on the popcorn was enumerated on selective xylose lysine desoxycholate (XLD) agar and non-selective Tryptic Soy Agar (TSA). For samples with Salmonella spp. populations less than the detection limit, its presence was detected using enrichment method outlined in bacteriological analytical manual (BAM). Results: The maximum surface temperatures obtained during microwave, hot air and electric popping methods were in the range of 120° to 130°, 200° to 210°, and 230° to 240° C, respectively. Salmonella spp. was not detected on popcorn prepared from non-inoculated corn using the three popping methods. Salmonella spp. counts of popcorn prepared from inoculated kernels were below the detection limit (-0.81 log CFU/popcorn) on XLD agar. The corn inoculated to 6.84, 2.70, 0.99 log CFU/kernel and popped in microwave oven resulted in survival of 0.68, 0.55, <- 0.81 log CFU/popcorn, respectively on TSA. The corresponding values for popcorn prepared using electric and hot air popping methods were 0.44, 0.18, 0.06 and 0.34, 0.12, <- 0.81 log CFU/popcorn, respectively. Salmonella spp. was able to survive the popcorn preparation process using any of the three methods. Significance: Salmonella spp. present on corn may survive the commonly used preparation methods used at home and proper care must be taken to prevent the contamination of the corn to minimize the risk. Abstract Book — 75 Poster

IAFP 2009 Program Book and Abstract Book

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