ABSTRACT
Two modified fluorescent enzyme immunoassays for the detection of Salmonella in food have been developed. Both of the new procedures, which substitute a colorimetric substrate for the fluorescent substrate and in which results are read visually or with a photometer, are modifications of AOAC method 989.15. The visually read procedure uses the same antibody-coated wells as in method 989.15. The colorimetric end point of the assay is determined by comparing the solution color to a color chart. The assay result may also be read in a photometer, if the solution is first transferred to a transparent microtiter well. The second procedure designed to be read in a photometer substitutes clear, antibody-coated wells for those used in the fluorescent assay. The colorimetric assays employ identical monoclonal antibodies for capture and detection of Salmonella as used in the fluorescent assay. In this comparative study, the performance of each new assay was consistent with the performance of method 989.15. These methods have been adopted official first action by AOAC as alternative methods for the detection of Salmonella in foods.
Subject(s)
Food Microbiology , Salmonella/isolation & purification , Colorimetry , Fluorometry , Immunoenzyme Techniques , Sensitivity and SpecificityABSTRACT
A collaborative study was performed in 13 laboratories to validate an enzyme immunoassay (EIA) procedure for rapid detection of Salmonella in foods. The EIA was compared with the standard culture procedure for detection of Salmonella in 6 food types: ground black pepper, soy flour, dried whole eggs, milk chocolate, nonfat dry milk, and raw deboned turkey. Uninoculated and inoculated samples were included in each food group analyzed. There was no significant difference in the proportion of samples positive by the EIA and culture procedures at the 5% level for any of the 6 foods. The enzyme immunoassay screening method has been adopted official first action as a rapid screening method for detection of Salmonella.
