Young Dutch company creating products for Salmonella detection

Faster detection of Salmonella contamination in the food chain

Check-Points B.V., established in 2002 and located in the Food Valley region, has developed a patented system for fast and specific identification of a range of microorganisms. The Premi® Test Salmonella is its first product available and was launched on the market by DSM Nutritional Products. It is an innovative DNA-based detection method enabling routine Salmonella subtyping to pinpoint Salmonella contaminations in the feed and food chain. Rapid, in-house Salmonella subtyping is essential to Salmonella reduction programs. With the Premi® Test Salmonella, Check-Points and DSM Nutritional Products offer the food industry novel and rapid solutions for Salmonella monitoring and serotyping of positive samples, which is vital in tracing the source of the contamination. This test enables corrective actions to be taken, which will lead to better control or eradication of the Salmonella problem within a specific production chain. Furthermore, the EU and the U.S. have set tough targets for reduction in the prevalence of certain Salmonella serotypes. Premi® Test Salmonella is an effective tool to meet these tighter governmental regulations.

Salmonella infections

Salmonella is named after Daniel E. Salmon, an American scientist who, along with others, helped to put the first U.S. meat inspections in place. His assistant, Theobald Smith, actually discovered this bacterium, on which they reported in 1885. Salmonella is a genus of bacteria that are major causes of food-borne illnesses throughout the world. The bacteria are generally transmitted to humans through consumption of contaminated food of animal origin, such as meat, poultry, eggs and milk. However, many other foods, including green vegetables, have been implicated in transmission as well. Most persons infected with Salmonella develop diarrhea, fever, nausea and abdominal cramps. While most patients recover without treatment, illness can be severe and sometimes even life-threatening in the young, the elderly and patients with weakened immune systems. There are many kinds of Salmonella bacteria, over 2,000 known serotypes, of which Salmonella typhimurium and Salmonella enteriditis are common examples.

The DNA extraction is a very simple procedure, starting with picking colonies from a plate

The microarray used for the detection of the Salmonella serotypes

Array in reader

Consequences of Salmonella contamination

Salmonellosis constitutes a major public health burden and represents a significant cost to society in many countries. In the United States, an estimated 1.4 million non-typhoidal Salmonella infections occur annually, with an associated cost estimated to be $3 billion (source: WHO website). In Europe, Salmonella continued to be the most frequent cause of food-borne outbreaks in 2007, accounting for four out of ten of those reported. Although the majority of salmonellosis cases occur individually, outbreaks attract a lot of media attention. Recent outbreaks of Salmonella in the United States include, for instance, an outbreak of Salmonella saintpaul infections associated with alfalfa sprouts which probably originated from contaminated seeds; an outbreak of infections caused by Salmonella agona associated with cereal products; and an outbreak of Salmonella typhimurium infections associated with peanut butter, and products containing peanut butter. In this last example, which turned out to be one of the worst known outbreaks of food-borne disease in the U.S. in recent years, at least 714 infected persons were reported in 46 states. Infection with Salmonella typhimurium may have contributed to nine deaths. More than 2,833 peanut-containing products produced by a variety of companies may have been made with the ingredients that were recalled by the peanut butter- and paste-producing ingredient manufacturer whose plant was the likely source of the outbreak (source: CDC website). This company has announced bankruptcy procedures (source: FDA website), hence, consequences of contamination can be far-reaching.

Premi® Test Salmonella

Modern Salmonella reduction programs benefit from including Premi® Test Salmonella in routine analysis, since this test is able to confirm and serotype Salmonella in one simple, rapid and reliable routine test, based on a PCR+microarray. At the moment, 98 serotypes, including the most frequently occurring serotypes, can be identified, with a 100% specificity and more than a 92% identification of the correct serotype. Furthermore, Premi® Test Salmonella reliably identifies serotypes of strains considered as "rough," which are not serotypable with the conventional Kaufmann White scheme. The test contains all the components to perform the assay, and is easy to implement in facilities with basic laboratory equipment. Benefits include accurate and reliable results in just 3 days, instead of 5-7 days for in-house serotyping, or even the 2-4 weeks required for third-party serotyping. In addition, it does not need the well-trained and experienced staff required for conventional serological methods. A 1 to 2 day training at your company's premises with a Check-Points or DSM technician and continuous online support will do. Through serotyping, the source of Salmonella contamination can be traced back to the vulnerable link in the chain, for instance, in the hatchery, the breeder flock, the feed mill, the grow-out farm, contaminated water, improperly composted manure, the processing plant, or to improper distribution or storage, or wherever the problem may arise.

Evaluation of the Premi® Test Salmonella was carried out by comparing its performance with classical serotyping on 443 strains. Results were reproducible and clear cut. Out of 62 represented serovars, 60 gave unique genetic profiles, while 2 were indistinguishable. It was concluded that the Premi® Test method showed interesting potential for routine laboratory testing (Int. J. Food Microbiol. 2008, 30:293-298). In another study, a Belgian reference laboratory compared classical serotyping and Premi® Test Salmonella over a 9-month period in which 754 strains of animal origin were tested. They concluded that Premi® Test Salmonella offered a valuable alternative to classical serotyping for laboratories performing routine analysis of Salmonella strains, assuming that the system has been validated beforehand with a significant number of strains originating from that particular geographical area (J. Clin. Microbiol. 2008, 46:4037-4040). Validation studies are being performed by various reference laboratories, and AOAC and Microval validation is currently in process. In addition, validation studies for an OIE certificate are also being carried out.

Check-Points is currently developing a range of other products in close cooperation with a number of leading international food producers. Some of these could be applicable to other microorganisms.

Joost Thijssen

Contact Details:
Joost Thijssen, PhD, Managing Director
j.thijssen@check-points.com
Telephone: + 31 317 453908

For further information visit the following websites:
www.check-points.com and
http://www.dsm.com/en_US/html/premitest/premitest_salmonella.htm