Methodology for detection and typing of foodborne microorganisms

Over the past decade many improvements have been seen in both conventional and modern methods for the detection of pathogenic bacteria in foods. Modif ications and automation of conventional methods in food microbiology includ e sample preparation, plating techniques, counting and identification test kits. ATP bioluminescence techniques are increasingly used for measuring th e efficiency of cleaning surfaces and utensils. Cell counting methods, incl uding flow cytometry and the direct epifluorescent filter technique are sui table techniques for rapid detection of microorganisms, especially in fluid s. Automated systems based on impedimetry are able to screen high numbers o f samples based on total bacterial counts within I day. Immunoassays in a w ide range of formats make rapid detection of many pathogens possible. Recen tly, there have been important developments in the use of nucleic acid-base d assays for the detection and subtyping of foodborne pathogens. The sensit ivity of these methods has been significantly increased by the use of the p olymerase chain reaction and other amplification techniques. Alternative an d rapid methods must meet several requirements concerning accuracy, validat ion, speed, automation, sample matrix, etc. Both conventional and rapid met hods are used within hazard analysis critical control point programs. Furth er improvements especially in immunoassays and genetic methods can be expec ted, including the use of biosensors and DNA chip technology. (C) 1999 Else vier Science B.V. All rights reserved.