[Extraction and concentration of Clostridium botulinum toxins from specimens (author's transl)].

In order to detect minimal amounts of Clostridium botulinum toxins in animal tissue or food specimens it is necessary to use an extraction method which results in concentration of the botulinal toxins. In the present examinations, artificially contaminated canned beans were used to develop a suitable procedure for extraction and concentration of botulinal toxins A-E. The procedure consisted of 4 steps: 1. Canned beans were diluted 1:2 with 0.1 m phosphate buffer pH 6.0. 2. The diluted material was homogenised with an "Ultra-Turrax" homogeniser for 20 sec. 3. The monogenised material was centrifuged at 4000 rpm for 30 min. 4. 15 ml of supernatant was concentrated using a "Millipore ultrafiltration chamber" (with a membrane capable of excluding all material with a molecular weight above 25,000). A pressure of 1.5 atmospheres was applied until the terminal volume was 0.5 ml. Following extraction and concentration, the samples were assayed for botulinal toxin in mice. Using this assay the concentration of the five toxins were shown to be as follows: Type A toxin: 19.0-fold toxin concentration Type B toxin: 14.8-fold toxin concentration Type C toxin: 20.6-fold toxin concentration Type D toxin: 28.2-fold toxin concentration Type E toxin: 112.2-fold toxin concentration