The contamination stops here: with 3M's express salmonella testing

3M helps food companies test for salmonella bacteria that can cause deadly infections.


3M’s Kevin McGoldrick held up two 3M Petrifilm Salmonella Express plates — one unused, left, and one tested which showed potential traces of salmonella.

Photo: Photos by DAVID JOLES •,

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Salmonella bacteria, which cause sometimes fatal food poisoning, have survived 50 years of scientific efforts to wipe them out.

3M Co. is part of the next-best solution: Trying to prevent salmonella contamination at food processing plants by using detective work to identify contaminated products before they are shipped to customers.

Food testing is an effort to head off one of the major sources of salmonella infections, which are often passed through turkey, chicken or eggs that haven’t been cooked well or stored properly, but are also spread through uncooked foods such as peanut butter, lettuce and bean sprouts.

Young children, the elderly or people with weakened immune systems are most at risk of salmonella infections. Nonfood sources of salmonella infection include other people and pet lizards, turtles and snakes.

After 30 years of producing salmonella tests for food processors, 3M is now trying to make the tests cheaper and faster to appeal to countries such as China and India, where food safety is only now becoming the priority it has been in the U.S.

“In essence, what 3M is trying to do is simplify a very complex microbiological process,” said Kevin McGoldrick, director of U.S. sales of 3M food safety products. “It allows users to simply and easily test for salmonella, and reduces the time to get a result. Time is money for food manufacturers, and this allows them to ship a product sooner.”

But despite decades of study, efforts to eliminate the naturally occurring salmonella bacteria in the U.S. have been unsuccessful. In some cases, food label warnings to cook or refrigerate the product haven’t been followed. In others, salmonella has been found in additional types of products, such as peanut butter, that don’t carry warning labels. The U.S. government has set testing requirements for food processing companies but they only involve spot-checking. Some contaminated products slip through.

“Similar to automobile accidents, salmonellosis is so common that only extraordinary outbreaks make the news,” Food Safety News, a trade journal, reported in January. “And yet, according to U.S. Centers for Disease Control and Prevention (CDC), it is the deadliest of foodborne outbreaks.”

On its website, the CDC says there are about 42,000 reported salmonella infections in the U.S. every year, but notes that “because many milder cases are not diagnosed or reported, the actual number of infections may be twenty-nine or more times greater.”

Despite the seemingly intractable problem posed by the bacteria, 3M hopes that by making salmonella tests cheaper it can broaden their use around the world and thus reduce the number of infections carried by food.

3M’s newest product, the Petrifilm Salmonella Express System “works well in low-labor-wage markets like Asia and Latin America, where they can’t afford to invest in higher technology and automation,” McGoldrick said.

The Express System product consists of a plastic film embedded with premixed nutrients that cause salmonella bacteria to grow in incubation chambers and become detectable in about 44 hours, McGoldrick said. The test, which can be used either on food samples or the work surface food is prepared on, takes half the time required by traditional laboratory methods, which involve manual mixing of nutrients, to determine if salmonella is present.

3M has similar Express kits with different mixes of nutrients to search for other types of bacteria. Collectively, the 3M tests are part of a $2.9 billion world market for all types of microbiological testing of food products, according to a report last year from Strategic Consulting Inc. of Woodstock, Vermont.

McGoldrick said the Express kits for international customers are less expensive than two sophisticated chemical tests that 3M sells to U.S. and European food processing plants. Those pricier tests include a midpriced 3M test kit that uses antibodies to find salmonella, and a high-end molecular test that searches for salmonella DNA.

But despite all 3M’s technology, McGoldrick can’t foresee a day when salmonella bacteria will be conquered, making testing for it unnecessary.

“Microorganisms, especially salmonella, are adept at evolving.” McGoldrick said. “Salmonella has such a high mutation rate that it can find ways to survive in different environments. Microorganisms like salmonella are becoming more immune to antibiotics.”

Steve Alexander • 612-673-4553

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  • The 3M Molecular Detections System detects salmonella and can test 96 samples at a time. The system can detect salmonella in 75 minutes.

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