Neogen ANSR test targets Listeria monocytogenes
ANSR for L. monocytogenes is the third test available for the pathogen detection system.
Listeria and Salmonella tests were both introduced in 2012 and have been AOAC-validated.
“At the outset, we knew that differentiating a single strain of a species at the molecular level from other members of that species presented a much more difficult challenge than identifying bacteria at the species level,” said Ed Bradley, Neogen’s vice president of Food Safety.
“Rather than rush a product to market, we waited to launch until we had the product performance that our customers have come to expect from us,” he told FoodQualityNews.
Simplify testing platforms
Neogen said customers and microbiological testers in general prefer to use the fewest number of testing platforms as possible to simplify training, ordering and testing logistics.
Working with customers, the firm said developing an assay for L. monocytogeneswas the natural progression after one for Listeria species.
“Neogen’s ANSR system allows testers to assay a single enriched sample for Listeria species or L. monocytogenes — or both,” said Bradley.
“If a positive result is determined using the Listeria species assay, the tester can immediately assay the same enriched sample for L. monocytogenes and have that result in only an additional 10 minutes.”
Combined with ANSR’s single-step enrichment, Neogen’s pathogen detection method for L. monocytogenescan provide definitive results in 25 hours from the time the sample is taken.
The test also uses the LESS Plus Medium, which can be autoclaved — allowing for larger batches of media to be prepared prior to use.
Not wary – just conservative
When asked if it found food firms open or way to changing methods, Bradley said they were conservative.
“The advantages of any new test method have to be sufficiently compelling in terms of time to result, cost, ease of use, higher accuracy or sensitivity, or better service from the manufacturer. Otherwise, why would customers change their current method?”
Neogen’s ANSR is an isothermal amplification reaction test method that amplifies the DNA of any bacteria present in samples to detectable levels.
The firm said it was designed to combine molecular-level accuracy with a scalable low-cost instrument and a methodology that can be put into a testing laboratory’s existing workflow.
Neogen said it will be pursuing an AOAC approval for the L. monocytogenes assay.
Matrices validating for the submission for possible approval include cantaloupe, hot dogs, Mexican-style cheese, liquid pasteurized eggs, sprout rinse water, guacamole and stainless steel.
