“Roka’s Atlas System integrates well with our LIMS,” Dr. Radcliff relates. “The automatic importation of results into the LIMS and tracking of TMA kit lot numbers simplifies the workflow and traceability, which in turn makes them easily auditable.”
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Dr. Chaney mentions that, along with continually expanding its footprint by developing unique applications for its current food testing products, Roka endeavors to provide support to its customers, and also works with strategic partners. “We strive to partner with the industry we serve in collectively advancing food safety,” he emphasizes.
Roka’s menu of automated pathogen detection kits includes Listeria spp., L. monocytogenes, Salmonella, Escherichia coli O157:H7, and non-O157 Shiga toxin-producing E. coli, as well as applications including semi-quantitative Salmonella. All of these kits utilize target capture, TMA, and HPA molecular chemistries, and these kits are utilized in Roka’s new applications, Dr. Chaney says.
“More recently, we have introduced a new kit for detection of Listeria spp. specifically in environmental samples, in addition to a novel workflow for use in mitigating the diagnostic challenges that may arise with use of industrial phage based processing aids,” Dr. Chaney adds. “We are currently validating some new and exciting options, such as media alternatives and new assay application parameters for our customers that we anticipate will confer a number of benefits and efficiencies to their operations.”
As general manager of Mérieux NutriSciences, Wendy McMahon, MS, CFS, oversees the company’s Silliker Food Science Center (SFSC) contract research laboratory, Crete, Ill.
McMahon believes matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectroscopy (MS) is an important tool for bacterial and fungal identification in food laboratories today. “It’s really used for determining unknown organisms, mostly spoilage and contaminations, with mold being a good example,” she points out.
Available commercially for less than 10 years, MALDI is a three-step soft ionization technique that allows the analysis of biopolymers such as DNA, proteins, peptides, and sugars, and also large organic molecules. The TOF is the type of mass spectrometer most widely used with MALDI, primarily because of its large mass range.
McMahon says it’s interesting that the microbiology world is using MS for bacterial identification, since MS is a tool used for chemical analysis. “Chemists get a kick out of this,” she quips.
Under McMahon’s leadership, the SFSC is launching the use of MALDI-TOF in the lab during the spring of 2017. “We expect hundreds of ID requests per month due to its quick time to result,” she predicts.
The SFSC is using bioMérieux’s VITEK MS to run its MALDI-TOF tests. “We made that decision based on the database,” McMahon relates. “Specifically, bioMérieux’s database has been established with an average of greater than 14 isolates per species and an average of 26 spectra per species, making it very specific. If an organism is not a part of the database (unidentifiable), then 16S ribosomal RNA (rRNA) gene sequencing can be used for identification.”
The time to result was also a deciding factor in selecting VITEK MS, McMahon adds, noting that it allows for faster investigations and decisions than getting identifications with gene sequencing affords.
“Microbiologists appreciate the quick turnaround time MALDI-TOF offers, less than 30 minutes once the isolate is ready, while requiring very little hands on time from a technician,” McMahon elaborates. “In contrast, the gold standard of 16S rRNA gene sequencing for bacterial identification takes a day of operations and a significant amount of hands on time.”
The SFSC has been using the 16S rRNA method for more than 10 years.
“MALDI-TOF is becoming more widely used throughout the food industry due to the quick results and ease of use,” McMahon says. “The clinical and pharmaceutical industries took to it first and the food industry is quickly catching on. MALDI-TOF’s use in food will increasingly provide companies with faster results when investigating spoiled product, mold contaminations or out of specification raw ingredient or finished product.”
Details to Work Out
There are details to work out in the increasingly more sophisticated world of food laboratory technology, especially with regard to the pathogen testing and detection end of things, says Lee-Ann Jaykus, PhD, the William Neal Reynolds Distinguished Professor in the Department of Food, Bioprocessing, and Nutrition Sciences at North Carolina State University, Raleigh, and also the scientific director of the USDA-NIFA Food Virology Collaborative.