MicroMessenger. Newsletter. 3M Microbiology Food Safety Products and Services. In this issue. News from 3M Microbiology Pathogen Testing a Global Need

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1 3M Microbiology Food Safety Products and Services Published by 3M Microbiology June, 2008 MicroMessenger In this issue News from 3M Microbiology...1 Criteria in Choosing a Pathogen Detection Method Did you know?...2 Tech Talk...4 3M Microbiology Black Pearl Award Winner...4 3M Tecra VIA Reliable and Trusted Pathogen Test Newsletter News from 3M Microbiology Pathogen Testing a Global Need Food safety is a major global, public health concern for all of us and requires highly integrated initiatives and practices to assure safe food through the entire supply chain from the farm to the consumer. This is further complicated by international trade and the import and export regulations governing the food and agricultural products shipped between countries. The entire food supply system is changing rapidly driven by many diverse factors including; globalization, food production/processing capabilities, value ad s to commodity foods, new learnings in the field of microbiology and the application of technologies to improve the control and detection of microorganisms. Reliable analytic microbiological testing for pathogenic organisms remains central to an effective process to assure food safety. Combined with optimized Quality Systems it helps assure the supply of fresh, wholesome and safe food to consumers worldwide. 3M Microbiology has been a committed leader in assuring food quality by supplying the food processing industry with 3M Petrifilm Plates worldwide for 25 years. Now with the 3M Tecra product offering, we intend to bring the same commitment of innovation and leadership to the pathogen testing needs of food producers and contract/reference labs across the world. 3M Microbiology s global team of business and expert technical service support can now provide our customers with the full value of a broad offering of quality and safety solutions while improving operational workflow efficiencies, a true integrated approach. Dr. Jim Farr, Global Marketing, 3M Microbiology Grain United States Vegetables Mexico Dairy Italy Beef Canada

2 Did you know? 3M Tecra Tubes By using the 3M Tecra Tubes you can boil and manipulate up to 94 samples for your pathogen test in one convenient-to-use compact space saving rack. This eliminates the need for numerous test tubes and racks to accommodate your samples. 3M Tecra Tubes come racked and are available either sterile or non-sterile for your convenience. Criteria in Choosing a Pathogen Detection Method Dr. Purnendu C. Vasavada Professor of Food Science, University of Wisconsin River Falls and Food Safety and Microbiology Specialist, University of Wisconsin Extension, working in conjunction with 3M Microbiology on a 1-year sabbatical. Microbiological testing in the food and beverage industry is critical to guide the development, adjustments to and validation of operations to assure the production of high quality and safe food products. Test methods must provide reliable, timely and cost effective results to provide value to the food producer. Advances in biotechnology have provided many new pathogen testing assay formats and enrichment protocols that provide more rapid and accurate results compared to traditional methods. DNA amplification systems, including polymerase chain reaction (PCR) and immunoassay based approaches are the most frequently used rapid methods and have been adopted by regulatory agencies and the food industry worldwide. In addition to assay improvements, approaches that facilitate the isolation and amplification of target/selective organisms have been developed, including the use of bacteriophage technology during enrichment for selective suppression of background flora. Improvements to pathogen testing must overcome many technical and scientific complexities including, food matrix variability s, competing micro-flora and evolving organisms. Continued innovation in assay format development may involve technologies such as new DNA/RNA amplification, biosensors, micro arrays, mass spectrometry alone or in combination to provide the next generation pathogen assay. Rapid methods offer speed, sensitivity and selectivity in pathogen detection, however, each method has limitations and challenges in meeting industry requirements concerning accuracy, validation in different sample matrices, complexity in performing assay, risk of cross contamination and cost. Some key criteria and considerations in selection and adoption of new alternative or rapid methods are discussed below. Selection of Rapid Methods The following are among the main factors and considerations in selection or adoption of rapid methods in a food microbiology laboratory: Speed: One of the primary considerations is speed. Many so-called rapid methods, while providing many advantages over traditional methods, require incubation and enrichment and hence, provide overnight or next-day results. Some newly developed microscopic, bioluminescence, flow cytometry, and PCR based methods are capable of giving results within hours, however, other criteria such as specificity, sensitivity and official method recognition, as well as instrumentation and cost, must be considered. Accuracy, Selectivity, Specificity and Sensitivity: Rapid methods should have a high degree of accuracy, which is a measure of the degree of response from target to non-target 2 Continued on Page 3 >

3 organism or analyte and includes selectivity and detection limit. The method should have false positive and false negative results as close to zero as possible. Providing a low detection limit is critical since most current regulations require zero tolerance in food, i.e. less than 1 organism per 25 grams of sample. While many methods specify a theoretical detection limit of 1 organism, they often require a short enrichment and practical detection limit of organisms per enriched sample. Validation: It is important to consider a method that has been independently validated because validation is essential in demonstrating that the new method can generate results that are comparable to, if not better than, the current method. Validation also confirms the specificity, selectivity and reproducibility of the method. The AOAC International Official Methods of Analysis sm validation program is well regarded by the food industry and regulatory agencies. AOAC-OMA, the highest level of validation program where the method is validated by a collaborative study involving 8 10 laboratories. The AOAC Performance Tested Methods status assures the test kit user that an independent assessment has been conducted and the kit performs as claimed. Test kits found to be in conformance with their claims are granted Performance Tested Methods status by the AOAC Research Institute. AFNOR and other International programs may be important to companies who follow iso test methods. Finally, a thorough, internal validation of a method using intended food products and matrices should be conducted prior to selection and adoption of the method. Sample Handling and Preparation: The rapid method should perform well with the samples and sample matrices to be tested. Background flora, debris, natural substances and components can interfere with a test method. This is particularly important in the new molecular testing methods where food may contain PCR inhibitors and significantly influence test results. Training and Technical Support: Some new rapid methods involve use of novel instrumentations and equipment that may require high-level technician training. Training requirements, technical support and timely service must be considered. Service contracts and availability of loaner or replacement equipment must be thoroughly evaluated and negotiated prior to adoption of the method. Cost Assessing the cost of a pathogen testing platform should include many variables that define the overall value provided and include the following: Material Costs: Assay, any instrumentation related cost, required sample prep/enrichment, media, reagents, other required supplies Labor and time costs to run the test, and keep personnel properly trained Operational Workflow: Does the test provide operational benefits? Is it easily adapted to and provides efficiencies to the operation? Test Reliability: Does the test minimize the costs associated with variability and false negative or false positive results? Quality, reliability and availability of services provided by the supplier Ability of supplier to provide broad value/offering for your quality and pathogen testing needs Microbiological testing of food and ingredients that is reliable, cost effective and provides results in a timely manner is crucial for the food processor s ability to meet food safety and quality challenges. There is an unprecedented choice of methods for food safety assurance in general and pathogen detection in particular. By considering the above mentioned criteria, you can select a method suitable for your operation. l Automation: Many new methods involve automated and semi-automated processing that include interpretation, data storage, and traceability options. Automation can involve sample preparation, sample handling and processing including addition of reagents and other assay steps. Automation may allow for testing of more samples at a time and reduce operator variability and errors. 3

4 3M MicroMessenger June, 2008 FAQ Tech Talk Tech Topic: Pathogen Tests Q The 3M Tecra Salmonella VIA and E. coli O157 VIA Tests suggest the use of Imbentin as a supplement. What is the Imbentin supplement and how is it used? A Imbentin is a surfactant designed to help emulsify samples to help ensure optimum recovery. It is used with samples that have a high fat content, such as ground meats or butter, etc. Imbentin requires steaming prior to use. Once the bottle of Imbentin is steamed, write the date on the bottle in indelible ink and store above 10º C (50º F); e.g., room temperature. The bottle of Imbentin should be used within 6 months of steaming. 3M Tecra Visual Immunoassay (VIA) Reliable and Trusted Pathogen Test Foodborne illness is caused by pathogenic bacteria or toxins produced by bacteria in food. The most common bacteria associated with food poisoning include Salmonella, Listeria monocytogenes, E. coli O157, Staphylococcus aureus and Campylobacter. Traditional methods for the detection of pathogenic bacteria from foods rely on culturing the bacteria onto agar plates. These traditional culturing methods are time-consuming, taking from three days to over a week to detect specific pathogens. The 3M Tecra VIA kits make detection faster and more convenient than traditional assays. The 3M Tecra VIA kits come with ready-to-use reagents and a flexible format with a microplate and divisible strips allowing 1 94 tests to be run. The 3M Tecra VIA kits are a reliable and trusted assay formats with many of the detection assays taking less than two hours. Heat killing the pathogen not only reduces the risk of cross contamination but makes sample handling safer. After enrichment*, an aliquot is removed and boiled for 15 minutes. This step is critical for several reasons; to kill the pathogenic organism if present in the sample and to solubilize the antigenic (detection) sites on the organism. The sample is now ready for testing using the 3M Tecra VIA kit. The 3M Tecra VIA kits detect specific pathogenic antigens by an enzyme-linked immunosorbent assay (ELISA) performed in a sandwich configuration. ELISA is a sensitive technique for determining if specific molecules are present in a mixed sample. This assay is based on the use of an enzyme to catalyze a reaction that generates a product detectable by colorimetric methods. The 3M Tecra VIA kits use specific antibodies to detect the presence of a specific pathogen or toxin in food, beverage and environmental samples. 3M Microbiology Black Pearl Award Winner The International Association for Food Protection (IAFP) recently selected 3M Microbiology as the 2008 recipient of the prestigious Black Pearl Award. The Black Pearl Award is given annually to one company for its outstanding achievement of corporate excellence in advancing food safety and quality. For the complete story, visit our website at * Toxin VIA kits do not require enrichment. Continued on Page 5 > 4

5 3M Tecra Visual Immunoassay (VIA) Continued from Page 4 > If the pathogenic organism is present, they are captured by specific high-affinity antibodies adsorbed to the micro-wells (Fig. 1), all other materials are washed away. Enzyme-labeled antibodies (the conjugate) specific for the pathogen are added and bind to the captured antigen to form an antibody/antigen conjugate and complete the sandwich configuration (Fig. 2). Following washing of wells, colorless substrate is added and if the target organism is present, a green color is produced (Fig. 3). Determination of results can be performed either visually or automated by using an ELISA plate reader. Negative results allow the immediate release of the tested product. Positive results are considered presumptive and must be tested further by standard culture identification media, biochemical tests and/or serological tests. The following are helpful tips to keep in mind when using the 3M Tecra VIA kits. Bring all 3M Tecra VIA kit components to room temperature before use. Always write the date of reconstitution (or expiration) on each vial of reconstituted reagent. After reconstitution, label the reagent lids to limit the chance of mixing the lids between reagents and causing cross contamination of reagents. After reconstitution of the reagents, gently rock the vial back and forth to bring the reagent into solution. It is not recommended to vigorously shake the vial. Reconstituted reagents have two (2) months shelf life; the conjugate has one (1) month shelf life after reconstitution. Refrigerate all components of the 3M Tecra VIA kit at 2 8 C when not in use. Do not freeze. The conjugate, positive control and the antibody coated wells are batch specific and cannot be mixed with other batch numbers from a particular kit. Following these tips will provide easier, more efficient testing. Testing for pathogens and toxins is an important means of assuring that a product is acceptable to ship. Whether you are testing raw materials, finished product or environmental surfaces in the production facility, the 3M Tecra VIA kits make testing fast and easy. 3M Tecra VIA kits are available to detect the following pathogens: Listeria Salmonella Campylobacter Staphylococcus aureus Pseudomonas E. coli O157 3M Tecra VIA kits are also available to detect the following toxins: Staphylococcus enterotoxin Bacillus diarrhoeal enterotoxin Staphylococcus enterotoxin ID test Fig. 1 Highly specific antibodies coated on the surface of the micro-wells selectively capture the target pathogen. Fig. 2 Sandwich configuration of the enzyme-linked antibodies highly specific for the target are added to the well and bind if the target pathogen is present. Fig. 3 Substrate is added to the well and a color is produced indicating the presence of the target pathogen. The 3M Tecra VIA kits have been adopted as routine testing by many food and contract laboratories around the world providing them cost effective, reliable methods for their pathogen and toxin testing needs. In addition to the 3M Tecra VIA kits, 3M also offers a wide variety of prepared and dry medias to address your testing needs. l Chris Binsfeld, Global Technical Service, 3M Microbiology 5