Comparison of Salmonella Bio-EnzaBead™ Immunoassay Method and Conventional Culture Procedure for Detection of Salmonella in Crustaceans

J Food Prot. 1987 May;50(5):386-389. doi: 10.4315/0362-028X-50.5.386.

Abstract

The sensitivity of the Bio-EnzaBead™ enzyme immunoassay (EIA) for recovery of Salmonella in crustaceans was compared to a standard cultural method. Presumptive positive samples by the EIA procedure were confirmed culturally by plating their respective selective enrichments and post-enrichment M-broth cultures on bismuth sulfite, xylose desoxycholate, and Hektoen enteric agars. Use of tetrathionate, selenite cystine, and M-broth cultures was necessary for reliable confirmation of positive EIA reactions. Of 287 samples tested, 129 were positive by culture, while 130 were EIA-positive and were confirmed from the M-broth and/or the selective enrichments. When M-broth alone was used for confirmation of positive EIA readings, only 112 samples were shown to be positive, while 127 were confirmed from tetrathionate and selenite cystine. The importance of using all three media to confirm positive EIA readings was clearly demonstrated. There was a large number (76) of positive EIA assays which could not be confirmed culturally. These uncon-firmed positives were probably due to a cross-reacting organism present in the lot of material tested.