In this proposal, the investigators seek to develop an inexpensive, sensitive, non-polymerase chain reaction assay that is simple enough to be used by food processors or regulators to screen for known food contaminants. The approach employs rolling circle amplification of pathogen targets using sequence specific "molecular padlocks", which we have used for detection of other bacterial targets.
Our ability to ensure the safety of the nation's food supply depends on the availability of accurate, rapid, dependable and inexpensive detection systems. The most reliable methods for assessing food contamination involve enrichment and selective culture conditions. Although sensitive enough to identify a single colony-forming unit, culture assays are time consuming, typically requiring 4 to 7 days. Over the past decade, researchers worldwide have developed several rapid diagnostic agents for common food contaminants. However, rapid and sensitive implementation of these procedures for routine food screening is hampered by the requirement for skilled operators,inhibition by food constituents, and expense. In this proposal, the investigators seek to develop an inexpensive, sensitive, non-polymerase chain reaction assay that is simple enough to be used by food processors or regulators to screen for known food contaminants. The approach employs rolling circle amplification of pathogen targets using sequence specific "molecular padlocks", which we have used for detection of other bacterial targets. We will first demonstrate the efficacy of this assay for L. monocytogenes, because of potential application to the dairy,blueberry, potato, meat processing and seafood industries in Maine. The long range goal of this study is to develop an automated procedure using a suite of molecular padlocks to screen for suspected food pathogens including Salmonella spp., E. coli O157:H7 and S. aureus.