AN ELISA FOR DETECTION OF BOTULINAL TOXIN TYPE-A, TYPE-B, AND TYPE-E IN INOCULATED FOOD SAMPLES

An enzyme-linked immunosorbent assay (ELISA) was developed to screen f or the presence of botulinal toxin types A, B, and E in inoculated foo d studies. A commercially available trivalent antitoxin (Connaught Lab oratories, Ontario) was used as a capture antibody and biotinylated fo r use as a secondary antibody. An avidin-alkaline phosphatase conjugat e coupled with an enzyme-based amplification system resulted in a high degree of sensitivity. Detection levels of purified neurotoxins in ge latin phosphate buffer were 9 LD50 for type A and <1 intraperitoneal m ouse LD50 for types B and E, respectively. Toxin produced by two-type F strains (proteolytic and nonproteolytic) was detected in a liquid la boratory medium. In a comparative study of over 490 samples of ground turkey meat inoculated with C. botulinum types E and nonproteolytic B, the ELISA gave no false negatives and 91 false positives. False posit ives were thought to be due to the presence of inactivated toxin or to xin levels insufficient to cause mouse death. Statistical analysis of these data showed an ELISA sensitivity of 100%, specificity of 70.6%, and an efficiency of 81.4% when compared to the mouse bioassay for det ection of botulinal toxins types B and E. Coffee intermediates inocula ted with proteolytic Clostridium botulinum types A and B caused nonspe cific death in mice but were negative for presence of toxin by ELISA.