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In humans, Salmonella infections are one of the three leading causes of food-borne illness and deaths annually. Human salmonellosis is recognized as an important zoonotic disease of worldwide importance and is gaining status as a potential trade issue. The CDC estimates that 95 percent of human salmonellosis cases in the U.S. occur throug food-borne transmission. This has increased pressures on the pork chain to identify methods to reduce pork contamination. The NPPC Safety Committee has recently discussed development of a pre-harvest Salmonella control program. However, the lack of prevalence data and an understanding of potential production risk factors inhibit the effective implementation of such a program. This paucity of information hampers the ability to quantitate the magnitude of the industry Salmonella problems and to perform farm-abattoir risk assessments for different levels of on-farm contamination. <P>
The objectives of this study are: <OL> <LI> Estimate the prevalence of serologic positive production sites in Iowa swine utilizing a commercial ELISA test on meat juice samples from the PRV case finding system currently in place. <LI> Categorize Iowa production sites using the new Danish classification scheme and compare with current Danish results. <LI> Develop a production-based survey instrument that is capable of accurately characterizing the management and herd structures of commercial swine units. This survey will be utilized in later studies to compare selected sites classified as Levels I, II, or III under the Danish system, and to determine if differences exist in production characteristics for these herds.
NON-TECHNICAL SUMMARY: Lack of information hampers the ability to quantitate the magnitude of the swine industry Salmonella problems and to perform farm-abattoir risk assessments for different levels of on-farm contamination. The purpose of this project is to develop a production-based survey instrument that is capable of accurately characterizing the management and herd structures of commercial swine units in order to identify methods to reduce pork contamination. <P>
APPROACH: A two-stage cluster sampling technique will be used. The sampled populations will be drawn from lots supplied by 8 Iowa abattoirs currently cooperating in the PRV case-finding project. These abattoirs harvest an estimated 85 percent of the Iowa population and represent over 25 percent of the national market swine harvest. A random sample of 1,500 Iowa production sites will be selected and flagged in the PRV database so that with each submission to an abattoir their sample identity can be automatically marked based upon their unique PRV laboratory number. ELISA results will be reported by laboratory number and captured on the PRV database. Aggregated results will be used to establish a Salmonella Level status for each site based on the current Danish standards. Once these sites have been classified, random subsets from each Level will be selected. These sites will be contacted with a production-based information survey designed to identify the presence or absence of known on-site risk factors. The data collected from this survey will be compared with the Level classification. The appropriate statistical analyses will be conducted to generate risk ratios indicating Salmonella Level status for various production parameters.