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. Modifications and automation of conventional methods in food microbiology include sample preparation, plating techniques, counting and identification test kits. ATP bioluminescence techniques are increasingly used for measuring the efficiency of cleaning surfaces and utensils. Cell counting methods, including flow cytometry and the direct epifluorescent filter technique are suitable techniques for rapid detection of microorganisms, especially in fluids. Automated systems based on impedimetry are able to screen high numbers of samples based on total bacterial counts within I day. Immunoassays in a wide range of formats make rapid detection of many pathogens possible. Recently, there have been important developments in the use of nucleic acid-based assays for the detection and subtyping of foodborne pathogens. The sensitivity of these methods has been significantly increased by the use of the polymerase chain reaction and other amplification techniques. Alternative and rapid methods must meet several requirements concerning accuracy, validation, speed, automation, sample matrix, etc. Both conventional and rapid methods are used within hazard analysis critical control point programs. Further improvements especially in immunoassays and genetic methods can be expected, including the use of biosensors and DNA chip technology. (C) 1999 Elsevier Science B.V. All rights reserved.