Evaluation of a monoclonal antibody‐based immunoassay for detecting type BClostridium botulinumtoxin produced in pure culture and an inoculated model cured meat system

摘要

A monoclonal antibody‐based amplified ELISA method for detectingClostridium botulinumtype B toxin was evaluated for its ability to detect the toxin in the supernatant fluid of pure cultures and after growth fromCl. botulinumspores inoculated into pork slurries. Slurries containing NaCl (1.5–4.5w/v) and polyphosphate (0.3w/v) were either unheated or heated 80°C/5 min followed by 70°C/2 h before incubation at 15°, 20° or 27°C. Presence of specific toxin was confirmed by mouse bioassay and results were compared with those of the amplified ELISA method. A total of 48 strains, consisting of 38Cl. botulinumand 10Cl. sporogenes(putrefactive anaerobes), and 140 slurry samples were tested. Cultures of eight out of nine strains of type BCl. botulinumand 73 of 101 slurry samples containing type B toxin were positive by ELISA; the remaining 28 slurry samples contained type B toxin at levels below or close to the detection limit (20 LD50/ml) of the type B ELISA. No falsepositive reactions occurred withCl. botulinumtypes A, C, D, E or F, or with the 10 strains ofCl. sporogenes.Toxin produced by one strain ofCl. botulinumtype B (NCTC 3807) was not detected by this single monoclonal antibody‐based amplified ELISA. With a mixture of two monoclonal antibodies, however, the toxin from NCTC 3807 could be detected without reducing the sensitivity of