IAFP 2009 Program Book and Abstract Book - AB163

Methods: A virulent, rifampicin-resistant Salmonella Typhimurium was inoculated onto the stem, styler, or equator of three common fresh citrus varieties (Valencia oranges, Satsuma mandarins, and Marsh grapefruit), and allowed to dry for 24 h. Six volunteers, three men and three women, hand peeled the fruit and collected the peel, edible segments, and gloves into whirl-pak bags. Each sample was massaged for 30 s in DE neutralizing buffer and enumerated from Tryptic Soy Agar supplemented with rifampicin. The influence of gender and citrus variety on the percentage of bacteria transferred per recipient surface was determined using statistical analysis. Results: No significant difference (P ≤ 0.05) was found between men and women or location of inoculum on Marsh grapefruit or Valencia oranges. The peel portion of Satsuma mandarins showed significant differences in gender and inoculation site. Percent transfer to edible segments ranged from 27.9% to 0% in Valencia, 5% to 0.1% in grapefruit and 3.5% to 0% in mandarins. Transfer to gloved hands ranged from 10% to 0% in Valencia, 2.1% to 0.1% in grapefruit and 11.6% to 0% in mandarins. Pathogens transfer from the whole fruit to edible portions and hands regardless of the location of inoculation. Significance: Pathogens present on the surface of fresh citrus have the potential to transfer to the edible portion during hand peeling. P3-41 Distribution of Listeria monocytogenes in a Frozen Spinach Plant: Impact of Changes on Sanitation Procedures on Contamination Patterns Julian J. Esquivel Hernandez, Beatriz L. Alvarez Mayorga, Leopoldo Orozco Ramirez, Aurea Hernandez Parada and MONTSERRAT HERNANDEZ ITURRIAGA Universidad Autonoma de Queretaro, Departamento de Investigacion y Posgrado en Alimentos/ Facultad de Quimica, Queretaro, South Introduction: Eating raw produce and Listeria monocytogenes have been associated to illness outbreaks. This pathogen, a gram positive rod of wide distribution in the environment, is able to thrive in food production facilities. To establish effective control measures for L. monocytogenes, it is necessary to generate objective information based on a scientific approach. Purpose: Our objective was to study the impact of sanitation procedures on the contamination profile of L. monocytogenes in a processing plant that produces precooked frozen spinach. Methods: The facilities were visited seven times during a three-month period. Samples of inert surfaces, water, and spinach (raw, precooked and frozen) were collected to detect L. monocytogenes using both USDA and FDA methods. Isolated L. monocytogenes strains were subjected to pulsed-field gel electrophoresis using ApaI and AscI. Results: A total of 412 samples (259 spinach, 122 surfaces, and 31 water) were collected. In the first three studies, the global incidence of L. monocytogenes was 18.4% (+/n = 37/201). After the third study, data were analyzed and changes to sanitation procedures were introduced, including new methods for cleaning and sanitizing equipment, utensils, and floors. The incidence of the pathogen for studies four to seven was 1.4% (+/n = 3/211). Spinach residues remaining on equipment was the most contaminated type of sample for both sampling periods. L. monocytogenes strains were grouped into eight and six pulsotypes with ApaI and AscI, respectively. One pulsotype was the most frequent and widely distributed in the processing plant (57.1%) even after the intervention steps were modified. Significance: Data suggests that specific control strategies for each food facility may be indispensable to control L. monocytogenes in a plant environment and reduce potential cross-contamination. P3-42 A Review of Gastrointestinal Outbreaks in Schools: Recommendations to Reduce Illness MARILYN LEE and Judy D. Greig Ryerson University, Occupational and Public Health, Toronto, ON, Canada Introduction: Confined environments, such as schools, provide opportunities for direct and indirect transmission of disease agents when children come in close contact with each other or when children touch common surfaces. Food offered to students through a lunch program or the cafeteria can become another means of transmission through contamination from an infected food worker or improper handling of raw products, especially meats. Exposure to contaminated water and educational field trips to farms may provide other exposures. Purpose: The purpose of this study was to review documented outbreaks of enteric illness in schools, published in the last ten years, to identify aetiology, mode of transmission, the number of children affected, and morbidity and mortality patterns. Methods: Searches were completed in electronic databases, public health publications and Federal, state and provincial public health Web sites. Reference lists were hand-searched to validate the electronic search methodology. Reports identified through personal communications with public health officials were included. Results: Etiology of the 121 outbreaks that met the inclusion criteria included: bacterial 50%, viral 40%, Cryptosporidium 7%, and multiple organisms 2%. Transmission routes recorded in 101 reports included: foodborne (45%), person-toperson (16%), waterborne (12%), and animal contact (11%). Actions to control the outbreak included: alerting public health authorities, health care providers, or the community to the outbreak (13%), treatment of cases and close contacts (12%), enhanced handwashing (11%) and increased vigilance during food preparation (8%). Recommendations were made retrospectively to prevent future outbreaks in 77 (64%) reports. Significance: Training and certification of food handlers could prevent foodborne outbreaks in schools. Children should be supervised on farm visits, handwashing strictly enforced and food eaten in an area separated from the animals. Staff and students should have a positive and continuous communication with public health authorities, including educational sessions and immediate reporting of possible outbreaks. Abstract Book — 163 Poster

IAFP 2009 Program Book and Abstract Book

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