Smaller, Stronger, Faster Labs

Food, glorious food!/We’re anxious to try it/Three banquets a day/That’s our favorite diet! —Charles Dickens, Oliver Twist

In these non-Dickensian times, the availability of food is not as much of an issue as concerns about food safety. Food is pouring in from all over the world, but ensuring its safety is a complex task. Food safety is inherently bound up in issues related to time, such as how long it takes to detect a problem or contaminant. And because time is money, there’s money to be made—or granted—in exploring the future of rapid detection.

“If you look over the last 12 months, two things have happened that are relevant,” said Marcos Cantharino, global business director at DuPont Qualicon in Wilmington, Del. First, there was a federally mandated determination, in contrast with the previous administration, to protect the consumer from foodborne diseases. And, second, “the government is looking for solutions that are either new technologies or new processes that can be in place at the source within food companies or at suppliers in general.”

As this mandate plays out in the legislative process, some funding is already available for innovation in rapid testing. The Defense Advanced Research Projects Agency recently invited proposal submissions for Systems and Assays for Food Examination methods of rapid detection, identification, and subtyping of Salmonella.

The Qualicon team is particularly interested because the microbe-detecting BAX system is their star player. The company recently received Emergency Response Validation certification for the detection of Salmonella in peanut butter, a distinction awarded by the Association of Official Analytical Chemists (AOAC).

The BAX system is streamlined for rapid detection. “Basically it’s a PCR [polymerase chain reaction] system, but we’ve eliminated all but a few of the 20-plus steps that might normally be taken in the PCR process,” said Cantharino. “We take all of the reagents that you would need for home brew PCR and put them into a tablet. … Just hydrate the tablet with the lysate and run it through the machine.” The results are noninterpretive: Red means you have a problem; green means there is no problem.

The simplicity and size of this benchtop system, as well as Qualicon’s global technical support, allow for on-site testing, a critical need for an increasingly globalized food industry. “We take some very sophisticated and advanced technology and make it into user-friendly applications. You don’t have to have a staff of advanced molecular biologists to use our product,” Cantharino said.

BAX, which recently received AOAC validation for Listeria and Vibrio assays, will make available, in the near term, new rapid tests for E. coli 0157:H7 and Cronobacter, “an important bug for infant formula companies.”

The BAX system Q7 incorporates innovative polymerase chain reaction technology to offer advanced DNA-based detection for food safety and quality testing.

The BAX system Q7 incorporates innovative polymerase chain reaction technology to offer advanced DNA-based detection for food safety and quality testing.

Microbial Strategies

Currently, the rate-limiting step in microbe detection is enrichment. One must grow a large population of a given bug to detect it. Daniel Fung, PhD, a professor of food science at the University of Kansas, is working to solve this problem. “I’ve developed a method which is excellent. There’s an enzyme Oxyrase that, when added to the culture medium, stimulates growth of many pathogens. This cuts the enrichment time from 12 hours to as few as four.” (J Rapid Meth Autom Microbiol, 2007). The discovery has already made its way into proprietary commercially available media. Dr. Fung did not patent the enzyme for enrichment purposes.

Another microbial strategy subject to recent improvement is concentration, or packing bugs into a smaller and therefore more detectable space. Matrix MicroScience, in Golden, Colo., recently launched the fully automated Pathatrix Auto system that relies on immunomagnetic separation technology. “This system is truly an innovation,” Dr. Fung said. Pathatrix uses paramagnetic particles to selectively bind target organisms from a wide range of complex matrices.

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