The recent outbreak of Salmonella caused by contaminated peanut butter which affected around 700 people, caused nine deaths and which led to a recall of >3900 food products, prompted the AOAC Research Institute in 2009 to set up an Emergency Response Validation (ERV) programme. The ERV program serves as a tool to support food producing industry and contract laboratories with officially validated methods. Human diseases caused by Salmonella are among the second most important food-borne infections worldwide. Recently, outbreaks were also traced back to contaminated peppers and sprouts.

To assist these laboratories with validated rapid method systems for detection of Salmonella in peanut butter containing foods, Merck KGaA and Biotecon Diagnostics GmbH successfully participated in this ERV with the following rapid methods:

This product combination was previously validated by the AOAC-RI in the Performance Tested Methods programme for the detection of Salmonella species in a variety of foods, including milk powder, egg powder, coconut, cocoa powder, chicken breast, minced meat, sliced sausage, sausage, smoked fish, pasta, white pepper, cumin, dough, wet pet food, dry pet food, ice cream, water melon, sliced cabbage, food dye, and milk chocolate. The method was shown to be equivalent to the FDA BAM and USDA/FSIS MLG reference culture procedures.

The ERV programme revealed that both the foodproof® Salmonella Detection Kit, in combination with the foodproof® ShortPrep I Kit, and the Singlepath® Salmonella did not lead to significant performance differences compared to the FDA-BAM testing method, even when peanut butter samples were spiked with extremely low levels of Salmonella typhimurium. Thus, both test systems are now approved by the AOAC-RI for the identification of Salmonella in peanut butter samples.

Further, the new foodproof® Salmonella Detection Kit, 5'Nuclease, which is based on the reliable TaqMan® real-time PCR technology, was also tested with the identical peanut butter samples. The results indicated 100% agreement with the approved foodproof® Salmonella Kit based on the Hybridization Probes technology. The AOAC-RI approval of the new foodproof® Salmonella 5'Nuclease Kit for a variety of foods is currently in progress.

The Singlepath® and foodproof® product lines are essential parts of Merck's unique and innovative program for the rapid and convenient manual or automated detection and confirmation of important food pathogens, such as Salmonella, Listeria spp., Listeria monocytogenes, E. coli O157, pathogenic Campylobacter, and of other pathogens. Both rapid test systems enable laboratories to analyse their food samples much more faster than the culture media based methods which usually takes up to 5 days.

As all rapid tests are dependent on the efficient pre-enrichment of bacteria in food samples, the foodproof® and Singlepath® products fit perfectly to Merck's comprehensive range of high-quality granulated dehydrated culture media.

For further information about the wide range of products available from Merck KGaA / EMD Chemicals for the growth, detection, isolation and identification of food- and waterborne pathogens and other microorganisms, please contact the local Merck organization or EMD Chemicals (for USA and Canada).