“We typically run about 100 GENE-UP samples every day,” says Amy Pass, BCN’s senior lab technician. “However, one of our clients operates 20 manufacturing plants throughout the U.S. Twice a year, in March and September, that company conducts biannual heavy environmental testing at all of its facilities. So then we are evaluating an additional 150 Salmonella swabs and 150 Listeria swabs per month for each of those 20 plants, which means we are running an average of 400 tests, but up to about 900 to 1,000 tests, per day, during those two months.
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“We have a better work flow with GENE-UP compared to other lateral flow methods we have used in the past,” Pass adds. “Since we started using this technology, we have experienced a 25 percent increase in our sample load, but the amount of time our employees spend running the tests has stayed the same.”
Another benefit of GENE-UP, Pass mentions, is that it provides a definite positive or negative result. “So there is no subjective decision looking at the lateral flow strip to see one line or two,” she says.
Colony Tests and Counter
The instrument is designed to analyze a variety of Charm’s Peel Plate microbial tests, which were introduced in August 2015, according to Robert Salter, MS, the firm’s vice president of regulatory affairs.
The tests are prepared media in a shallow dish with an adhesive top. “They are aseptic ready-to-use tests that are simply rehydrated with the food or food dilution, and incubated at times and temperatures appropriate to the microbes being detected,” Salter explains. “Colonies appear as colored spots that are visually counted or automatically counted by the Peel Plate Counter. An air gap between the plate and cover allows colony quantitation, picking and determination of microbial morphology.”
Currently there are Peel Plate tests for aerobic bacteria (Peel Plate AC, introduced in August 2015), coliform bacteria (Peel Plate CC, introduced in 2016), Enterobacteriaceae (Peel Plate EB, introduced in 2017), yeast and mold (Peel Plate YM, introduced in 2016), heterotrophic bacteria in water (Peel Plate HET, introduced in January 2016), and coliforms/E. coli (Peel Plate EC, introduced in August 2015) for use in dairy products, ground meats, other foods, contact surfaces, and water.
“The Peel Plate AC uses standard plate count formulation with 48-hour incubation,” Salter relates. “Peel Plate EC and CC use coliform selective media with enzyme color substrates with 24-hour incubation. The Peel Plate YM (yeast and mold) tests use conventional potato dextrose formulation with three to five-day incubation. The Peel Plate EB (Enterobacteriaceae) tests use selective EB formulation with 24 to 48-hour incubation. And the Peel Plate HET (heterotrophic plate count) test uses R2A formulation for quantifying bacteria in water with three to five days incubation.”
The new Colony Counter reads all of the aforementioned Peel Plates, Salter says.
Additionally, Charm offers a high volume version of Peel Plates CC-HVS, YM-HVS, EB-HVS, and EC-HVS, designed for a 5 milliliter (ml) sample, typically used for food plant sponge sampling of the production environment, for greater sensitivity in ready to eat foods, and to test water. “These are viewed visually and not yet supported by the Peel Plate Counter,” Salter says.
Salter believes the Peel Plate offerings are an improvement on many existing simple-to-use microbial test products. “The Peel Plate provides a ready-to-use platform that is self-wicking, stackable, and resistant to sample pH/disinfectant effects,” he relates. “Charm Peel Plate tests are simple to interpret color spots that are specific without the need to confirm, but will allow traditional picking of colonies for additional microbial isolation, testing, and identification.