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Salmonella and DNA Detection Methods by Kimberlee Shaffer
Issue Date: April / May 2009
“Four types of Salmonella found in pistachios”, “42 sickened in California, Oregon, Washington and Nevada tied to Spices”, “Salmonella in Nebraska, Iowa, Kansas and South Dakota tied to Sprouts” and “Salmonella typhimurium make 691 ill in 46 states tied to peanut butter”. These are but a few of the headlines we’ve seen over the last few months.
Salmonella is one of the most commonly reported enteric disease as well as the second most common food-borne illness. In 2005 the CDC reported that there were approximately 30,000 confirmed cases of Salmonella poisoning, and an estimated 1.4 million cases occurring annually in the United States. Of those reported cases there are about 600 deaths a year, or in other terms, 31% of all food related deaths are due to Salmonella infections.
Salmonellosis can result from the ingestion of:
- Contaminated ingredients particularly in institutional kitchens and restaurants.
- Polluted surface water and standing water (such as in shower hoses or unused water dispensers),
- Unhygienically thawed poultry (the melt-water contains many bacteria).
- Raw eggs from Salmonella-infected poultry (the Salmonella can be on the eggshell as well as in the egg mass).
- Infected eggs and milk, as well as egg containing products, when not prepared, handled, or refrigerated properly.
- Meat and seafood, if prepared incorrectly or somehow become infected with the bacteria.
- Tainted fruits and vegetables
Theobald Smith, a research-assistant to Daniel E. Salmon, discovered the first strain of Salmonella in 1885. Since that time, the number of strains of Salmonella known to cause illness has increased to over 2,300. Foodborne illness usually arises from improper handling, preparation, or food storage. It is important to use proper safe-handling techniques both at home and in the workplace. Good hygiene practices before, during, and after food preparation can reduce the chances of contracting an illness.
Eurofins Scientific’s Des Moines, IA location uses, the “Assurance GDS” system from BioControl in order to provide its clients with the best possible combination of accurate Salmonella detection and rapid turn-around-time. Our clients have a need for fast results so products can be rushed to market both in the US and abroad.
The Assurance GDS system is a DNA detection system that uses proprietary magnetic particles to capture the target organism (e.g., Salmonella) from an enriched sample. This “concentration step” increases the target DNA concentration and allows for a shorter enrichment time. It focuses on highly conserved target gene sequences ensuring greater specificity with fewer indeterminate or false positive results. This procedure will give you a confirmed negative result within 24 hours of the receipt of the sample by the lab. However, if there are indications that the result is positive for Salmonella the samples will be carried through an additional confirmatory step. Completion of such samples will take approximately 5 days from receipt of samples by the lab.
According to BioControl the “Assurance GDS” system has repeatedly been proven comparable to or better than current USDA or FDA reference methods across a wide range of matrices. It is because of this fact that Eurofins promotes this method with confidence.
For further information and comments, please contact Kim Shaffer at kimberleeshaffer@eurofinsus.com.
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