RAPID AND ALTERNATIVE SCREENING METHODS FOR MICROBIOLOGICAL ANALYSIS

Automated analytical instruments for enumerating indicator organisms a nd diagnostic test kits for pathogens can be used in food microbiology to screen samples and to replace conventional cultural and confirmati on steps. Such methods are now available for rapid detection or estima tion of groups of (indicator) organisms, pathogenic microorganisms, ba cterial toxins and mycotoxins, and molds. These alternative methods ca n be classified by the principles on which they are based: modified co nventional methods, instrumental measurement of bacterial metabolism, bioluminescence, immunological techniques, DNA techniques, and combina tions of these techniques. To meet user expectations, test kits must b e accurate, sensitive, specific, rapid (24 h or less), easy to use, an d labor-saving, They must also offer the possibility of computerizatio n, a low detection limit, and low investment and running costs. The pa per compares the ability of alternative methods to meet these criteria . Variations were found, depending on the techniques used and the targ et organism of the analysis. Economic reasons can determine whether al ternative methods can be used routinely. Adoption of these screening s ystems also can be hampered by lack of internationally coordinated and accepted validation protocols.