Currently, rapid microbial tests for pathogens are based on technologies such as immunoassays, chromatography and polymerase chain reactions. “I believe the enzyme-linked immunosorbent assays (ELISAs) and modified/adjuncts are the most commonly used methods,” says Purnendu Vasavada, Ph.D., food science professor, University of Wisconsin-River Falls. “This is due to their familiarity, convenience, regulatory and industry acceptance, and affordable cost.”
Modified/adjunct tests combine several conventional tests into convenient rapid test kits. For example, 3M's Petrifilm™ Rapid S. aureus Count Plate combines the three-plate Baird-Parker agar and tube coagulase tests for Staphylococcus aureus in a single test procedure. It consists of a sample-ready Petrifilm plate coated with modified Baird-Parker nutrients. The user places a small blue disk that has been coated with a microbial growth indicator and a thermonuclease-reactive agent within the plate's well during the final steps of the test.