Abstract
The isolation and identification of the infecting organism in contaminated foods is usually beset with difficulties and successful results are not the usual outcome. Negative findings often are due to the fact that it is impossible to examine the whole sample of the incriminated food bacteriologically. Since the pathogenic bacteria are usually few in number, and are not distributed throughout the food, it is more or less a matter of luck if one succeeds in isolating an organism which might justify the suspicions. If one attempts to increase the number of the specific bacteria by enrichment through incubation, he at the same time increases the number of saphrophytes, and thus adds to his difficulties. We find that the entire sample of suspected food can be advantageously analyzed for the presence of any suspected organism, or their split products (in addition to an attempt to isolate individual bacteria), by the following procedure.
The whole of the sample of food is chopped up and an extract made from it. This extract is concentrated so that all the specific bacterial protein is collected in a very small volume of liquid. 1 This concentrated solution is then tested against a set of specific immune sera. We have been able to detect by this method the presence of B. botulinus protein in 20 gram samples of artificially inoculated food, where the concentration of toxin was so small that it would have required giving at least 7 grams by mouth or 1.3 grams by injection into a mouse of 15-20 grams to obtain a positive result.
This method enables one to determine the presence of a suspected organism in contaminated food within 24 hours after receiving the specimen.
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