Methods for Health Risk Assessment by Clostridium botulinum in Biocompost
In recent investigations in 66 out of 143 tested samples of biocompost or substrates containing biocompost Clostridium botulinum was detetcted.
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Abstract. In recent investigations in 66 out of 143 tested samples of biocompost or substrates containing biocompost Clostridium botulinum was detetcted. In commercial potting soils, containing 50% biocompost, even at the purchase day, botulinum toxin was found in the plastic bags.
Obviously, • the number of cases of botulism in animals has been constantly increasing in the past years; • demands for quality control of human food make it necessary to reduce any contamination of the soil; • physicians need to become aware of the importance of human botulism. The pathogen Clostridium botulinum endangers health and life of man and animals by production of a very potent metabolite, the Botulinum Neurotoxin (BoNT). It is an anaerobic bacterium, ie., it multiplies and forms toxin under exclusion of oxygen. Under certain conditions it is even able to create its own anaerobic micro-environment in aerobic atmosphere, supporting multiplication. Clostridia are sporeformers, ie., they may survive adverse conditions very well. By the so-called hygienisation during compo sting possibly not all spores are destroyed. As a result surviving spores will multiply during subsequent curing and storage in compost. The nutrients, warmer temperatures, humidity, and exclusion from air form ideal growing conditions. The different influence factors will be discussed. The laboratory proof of bacteria and toxins is complicated due to the fact that internationally only the mouse bio-assay for food and pathological samples is accepted which takes at least 5-10 days for completion. New field and laboratory tests for compost and soils were established. First results are presented.
Problem The disease botulism is caused by neurotoxins (BoNTs) produced by Clostridium (C botulinum). The classical form of this normally fatal disease is the inhibition of neurotransmitter release at the neuromuscular synapses, which lead to paralysis of muscles. If the thoracical muscles are affected, death will follow by suffocation;
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Institute for Tropical Animal Health, University of Goettingen, Kellnerweg 6, 37077 Goettingen, Germany, e-mail: [email protected] H. Insam, N. Riddech, S. Klammer (Eds.) Microbiology of Compo sting © Springer-Verlag Berlin Heidelberg 2002
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the sensorium remains undisturbed (Smith and Sugyiama 1988; Seifert and Bohnel 1995). BoNTs are the most potent biological metabolites. In standard human and veterinary medicine, botulism is almost completely neglected. There are two reasons for this: evidence of its occurence is rare, and these cases are very often misdiagnosed. The experience of our laboratory shows that in reality there are numerous botulism cases in man and animals. Estimates suspect about 500-1000 dead infants per year in Germany from sudden infant botulism, although officially only 1-2 cases are reported anually (Behrens et al. 1998; Bohnel et al. 2001 b). In cattle we would estimate certainly more than 1000 cases per year (Bohnel 1999). However, there is another recently detected form of the disease, mai
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