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<p>The overall goal of the project is to provide a novel method for reducing carcass contamination with zoonotic pathogens such as serotoxigenic E. coli, Salmonella, Campylobacter, etc. This particular project focuses upon reducing the bacterial and pathogen load on the hides of processed cattle. The initial projected phases are as follows: </p>
<p>1. Determine the in vitro chelating agent dose required to inactivate two or more logs of STEC in under five minutes. </p>
<p>2. Obtain sections of hide from bovine necropsy animals and use a range of doses of the chelating agent to assess its capability to reduce total bacteria counts in less than five minutes. </p>
<p>3. Spike bovine necropsy hides with varying doses of STEC and measure killing curves of the chelating agent (dose and time variables). </p>
<p>4. Employ the optimal dose of the chelating agent on whole animal necropsy specimens and assess reduction of total counts of bacteria and spiked STEC </p>
<p>5. Develop the field test protocol in colloaboration with FSIS and FDA for utilizing the chelating agent on live animals and evaluate it under experimental conditions and make refinements where necessary </p>
<p>6. Field test the protocol in very small, small and large processing facilities </p>
<p>7. Complete field testing and risk assessments for reducing pathogen loads on hides The expected outputs will be a novel approach utilizing FDA approved food preservatives to significantly reduce or eliminate zoonotic pathogens on hides and carcasses at the processing plant. This will replace other chemical methods that do not possess this optimal approach. We will work with Dr Jim Keen at the University of Nebraska at Lincoln on this project.</p>
<p>NON-TECHNICAL SUMMARY:<br/> Of more than 100 serotypes that cause human disease, STEC O157 is the most common in the US, producing ~73,000 illnesses annually at an incidence of ~1 case per 100,000population. STEC O157 is a perennial and costly food safety concern. Contact with infected cattle or ingestion of contaminated meat, especially ground beef and non-intact beef, are primary illness vehicles. STEC O157 does not sicken cattle, and most US beef and dairy cattle herds are STEC O157 colonized in summer. Cattle hides and carcasses at slaughter can be heavily contaminated. Cattle hides are the primary and proximate source of meat contamination, but cattle gut infections are the ultimate zoonotic source. Over 50% of shiga-toxin producing Escherichia coli (STEC) are pathogenic with clinical symptoms in infected humans ranging from diarrhea to hemolytic urinary syndrome.
<p>Impacts/Outcomes: <br/>The benefits of this project will be realized when we provide a more effective method to reduce the potential for carcass and meat contamination with harmful bacteria. This will provide an added measure of quality and safety for the consumer. Section 4 pathogen reduction meat quality.</p><p>
APPROACH: <br/>This project approach is novel in that it employs FDA approved food preservatives to reduce total bacterial counts and pathogen loads on hides and carcasses in the processing plant. The study objective will be attained by employing a latin square study design where samples of cattle hides previously rubbed with a non-toxic variant of STEC, are then treated with various EDTA solution concentrations. The variable factors of the latin square used in this study are the STEC concentration, EDTA dose, and reaction time. Post and pre treatment cultures will be used to assess success of the experiment. Similar cuts of clean and dry hides from both sides of the cattle will be taken after humane slaughtering at a local, USDA inspected, processing plant. Cultures of different doses of nonpathogenic STEC strains will be diluted, and then specific sites on hides will
be inoculated with a brush previously soaked with the diluted cultures (10,000 -100,000,000 cfu/ml). Treated hides will be sprayed with different concentrations of the EDTA preparation (e.g. 50-200 mM ). Hides will be sampled by swabbing with a sterile sponge which simulates a primary mode of bacteria transfer from hides onto carcass meat. Sponge samples will be taken for centrifugation, and then will be plated using a spiral plating system on MacConkey Agar with Sorbitol HDx media, followed by incubation at 37 C for 24 hours. The samples will be plated in triplicate per time point. The time points assessed will be Time 0, 30-60-90 seconds-2-3-4-5 minutes. A confirmatory multiplex PCR assay will be done to detect the shiga toxins. Latin square study design will be used to assess success of the treatments. From previous experience using EDTA in milk, we anticipate this chelating agent
will do well inactivating this pathogen. Should this approach work as expected, this project will become a multi-state collaborative effort with Dr Jim Keen at the University of Nebraska at Lincoln.
</p><p>PROGRESS: <br/>2011/01 TO 2011/12 <br/>OUTPUTS: This project is still early in its timeline. Protocols have been developed for treating the hides, then assessing reduction in microbial loads. These protocols are under review by an outside expert panel. Any adjustments recommended with be implemented by our laboratory. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.</p>