The U.S. Centers for Disease Control and Prevention use data from cases of foodborne illness to estimate that each year, 31 major pathogens cause 9.4 million episodes of foodborne illness, over 55,000 hospitalizations and over 1,200 deaths. Many foodborne illnesses are caused by Salmonella, Escherichia coli, Campylobacter and Listeria.

Molecular methods for food pathogen detection continue to improve, as more emerging pathogens, like Shiga toxin-producing E. coli (STEC), are being described around the world in molecular terms. The ability to track a source of foodborne illness thus cannot be performed using non-molecular methods. Additionally, the use of real-time polymerase chain reaction (PCR) methods has the benefits of automation, high sensitivity, high precision and accuracy and the flexibility to assay for more than one pathogen simultaneously.

As laboratory director for the Dried Fruit Association (DFA) of California, Thomas M. Jones was looking for just this type of flexibility.

“DFA chose Bio-Rad’s system due to its capability to run different assays (i.e., Listeria spp., Salmonella and E. coli O157:H7) at the same time; the false-positive rates are much lower than the system we were using at the time. In addition, the system works with the matrices that we deal with, such as pistachios, almonds, walnuts, raisins and blueberries. We like the fact that we do not have a lot of invalid results or interference from the varieties of commodity matrices that our company receives for analysis.”

DFA of California, a non-profit trade association of dried fruit and tree nut processors that represents approximately 80 firms that process the majority of these commodities in California, was created over 100 years ago to promote a better understanding among growers, processors and purchasers of dried fruit and tree nuts. DFA offers food safety, laboratory and commodity inspection services and collaborates with industry and academia on research related to food safety.

When asked what the advantages were in choosing Bio-Rad’s kits, Jones focused on the Bio-Rad MiniOpticon real-time PCR system, which comprises a compact, two color, real-time detector built on the MJ Mini™ thermal cycler. It is the smallest and most portable real-time PCR system available. Also contributing to the discussion was Mai Yang, microbiology manager of DFA, who added, “The advantages of the MiniOpticon are the capability to run different assays and get results within 2 hours, compared to some other PCR systems that take 3 hours to receive any results.”

The different assays that Yang refers to are Bio-Rad’s iQ-Check kits, which are optimized for fast, qualitative detection of major pathogens in food and environmental samples. The kits utilize real-time PCR as the analysis platform. Two instrument platforms are available to meet every user’s needs. A 96-well instrument is suitable for high-throughput analysis, with the ability to run four instruments from a single computer at the same time. For lower-volume users, the 48-well MiniOpticon real-time PCR system is available. Additionally, Bio-Rad offers enrichment media, real-time PCR detection systems and software for automated analysis. The specific iQ-Check kits available include the following:

•    iQ-Check Cronobacter spp. Kit  

•    iQ-Check Campylobacter Kit  

•    iQ-Check Escherichia coli O157:H7 Kit  

•    iQ-Check Listeria spp. Kit  

•    iQ-Check Listeria monocytogenes II Kit

•    iQ-Check Salmonella II Kit  

•    iQ-Check STEC Kit  

•    iQ-Check Salmonella Enteritidis Kit

Bio-Rad’s assays allowed DFA to arrange a work schedule to get results into their clients’ hands faster with the confidence the company requires.

“Using the Bio-Rad MiniOpticon has reduced the numbers of test kits being wasted due to invalid results and reduced the need for confirmation agars due to fewer false-positive results,” Yang said.

DFA of California’s mission is to impact lives through food safety and quality leadership. With their vision to be the most reputable, innovative organization for food safety and quality, DFA knows that it needs an outstanding partner to accomplish its values of customer service, integrity, efficiency, accountability, innovation and passion. Bio-Rad’s offerings provide the reliability and consistency for DFA to meet all of their goals.

As a powerful alternative to reference methods, iQ-Check kits allow rapid, qualitative detection of major pathogens in food and environmental samples. They are optimized for real-time PCR with Bio-Rad detection systems.