Epidemiology of Salmonella in Almond Production and Processing

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Risk factors will be assessed, a questionnaire developed for farmers and soil and stockpiles will be evaluated to determine the longterm survival of Salmonella in orchards.</p>
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Drag swabs will be dragged diagonally through the orchards in one direction and diagonally back to collect any Salmonella Enteritidis Phage type 30 (SE PT30). Samples of sand, soil, dropped almonds and water also will be collected and tested for Salmonella. Risk factors for the survival and growth of SE PT30 in the almond production environment will be assessed. Almond hulls and shells will be collected from a huller/sheller. Hulls and shells will be ground separately using a grain mill and will be inoculated with SE PT30 that has been selected to be resistant to nalidixic acid.</p>
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In addition, wetted ground hulls and shells will be mixed with various concentrations of orchard soil prior to inoculation with SE PT30. Inoculated mixtures will be incubated at 20 and 35 C (68 and 95 C). </p>
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Also, SE PT30 strains will be marked with a fluorescent protein and used to examine by microscopy the attachment, survival and growth of the strain on hulls, shells, nuts and other almond-related tissues. </p>
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In addition, SE PT30 strains isolated will be studied to determine methods for discriminated them and whether they are similar. Populations of SE PT30 will be measured over time on Bismuth Sulfate Agar with added nalidixic acid using standard microbiological methods. Risk factors for the presence and persistence of SE PT30 in the almond production environment will be evaluated. Farmers will be interviewed using a questionnaire and representative environmental samples will be taken for Salmonella analysis. <br>
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