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<OL> <LI> Develop rapid, single tube, chemiluminescent assays for Listeria, E. coli, Salmonella and other foodborne pathogenic organisms which will be cost effective, simple to use, and compatible with commerical handheld luminometers. <LI> Develop the statistical correlation data demonstrating substantial equivalance to current detection and enumeration methods.<LI> Validate assay with environmental samples from commerical food processors. <LI>Examine environmental factors presenting interferences with the optical assay. <LI>Beta test assay in food processing facilites will be initiated.
NON-TECHNICAL SUMMARY: There is a great need for sensitive "real-time" analysis of food environments and products for the presence of pathogenic microorganisms. The positive economic and food safety issues that would be addressed if this type of technology is made available would have a great impact on the food industry. This technology would be extremely useful in the application of microbiological verification and validation of HACCP (Hazard Analysis Critical Control Point) systems that are mandatory in much of the food industry. <P>
APPROACH: <BR> 1. Commercial antibodies for the specific pathogens are bound to tubes. Chemiluminogenic derivatives of nisin are prepared, from which a nisin-cobalt complex is prepared. The bacterial culture or environmental sample is placed into the tubes containing the specific bound antibodies for pathogen of choice. After incubation, the tubes are washed and the nisin-cobalt probe added. The complex probe/pathogen is detected using the luminol-hydrogen peroxide system. Antibiotic/metal probes will also be developed for the gram-negative pathogens. The rapid, single tube assay will be optimized. <BR> 2. Data analysis will be done by subtraction of a sterile background control from the raw sample signal, divided by the sterile control signal. The value is the background corrected signal to background ratio. Chemiluminescent signals will be obtained from serial dilutions of stock cell suspensions and correlated to the enumeration data obtained from plate counts of the dilutions. <BR> 3. Environmental samples will be collected from actual food processing facilities and the assays will be conducted in addition to the traditional methods to correlate the results of the chemiluminescent probe to the traditional methods now being used. <BR> 4. Potential substrates that might interfere with the optical assay could include, strong alkaline materials, oxidizers and redox-active metals. Unknown salts, soils and heavy metals could potentially contribute to measurement error, these factors need to be examined with authentic samples of various origins. <BR> 5. Several food processing facilties will be used to beta test the probes developed in the field.<P>
PROGRESS: 2002/10 TO 2007/09 <BR>
OUTPUTS: Activities: A rapid, single tube assay for Listeria was developed and validated both in the laboratory and in the field at several food processing facilities. An AOAC approved method was provided after extension experiments were conducted. The product is now available commercially. Services: This product was used to work with facilities that have had outbreaks or recalls to rapidly determine the presence of the pathogen in their facility and to train sanitation workers on how to clean and sanitize properly to prevent the spread of Listeria. Dissemitation: Several workshops were conducted to train food industry personnel in the use of this product for environmental analysis of their food facility for Listeria. This product provides the user the information needed to prevent contamination of food products by controlling the organism within their facility. We worked with several major food companies nation wide to introduce this product into the industry. <BR> PARTICIPANTS: Research and outreach was conducted by both a private company, Paradigm Diagnostic, Inc. and graduate students in the Department of Food Science and Nutrition. We partnered with both small and large food companies in obtaining the field data needed to validate the assay. In addition, we trained Minnesota Department of Agriculture inspectors in the use of the product so that they could help introduce it to the small meat and poultry facilities in Minnesota. We also held workshops for the industry on the importance of testing for Listeria in their food facilities and how this product would provide a more rapid assay for the presence or absence of Listeria. We worked with several companies that had Listeria issues within their facility to develop better sanitation programs. <BR> TARGET AUDIENCES: Meat and poultry facilities are required to conduct Listeria testing. This assay provides a more rapid feedback as to the presence or absence of the pathogen. In addition, many other food facilities, even though they are not required to conduct Listeria testing, have adopted this assay to ensure that they have control over Listeria in their facilities.
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IMPACT: 2002/10 TO 2007/09 <BR>
The development and use of this assay in the food industry has provided a rapid response to determine the presence of the pathogen, Listeria, in the environment of the food facilities. This has allowed the food industry to take immediate action and prevent the potential contamination of the food product. The rapid nature of this assay allows the facility to hold product for only 24 hours to determine if there is a potential contamination issues. This assay has helped train food employees how to properly clean and sanitize by providing rapid feedback if the equipment or environment is contaminated with Listeria and proper action can be taken more quickly.