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close this bookBioconversion of Organic Residues for Rural Communities (UNU, 1979)
close this folderBioconversion products: toxicology - problems and potential
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The non-gaseous products from bioconversion of organic residues fall into the category of materials known generically as single-cell proteins (SCP). Methods for evaluating the potential toxicity of these materials in food or feed preparations have been developed and put into practice in recent years. In common with procedures for the similar evaluation of food additives and pharmacologically active substances required by most regulatory authorities, these methods are extensive, expensive, and time-consuming

It is doubtful whether either the facilities or the funds to carry out such procedures would be deployed for rural community projects in non-industrial countries There is, consequently, the danger that little or no long-term toxicological evaluation will be performed in these cases.

The suggestion is made that, when a new source of food is just a novelty, the situation is quite different from that prevailing when it is a necessity. A different problem may justify a different solution. To determine an acceptable level of safety in these cases for SCP produced by bioconversion processes, it is recommended that the long-term feeding studies with laboratory animals be replaced by the recently developed tests for mutagenicity, using bacterial or mammalian cell systems. These are rapid and relatively inexpensive; they do not require elaborate equipment, and give a high degree of correlation with the results obtained in studies of in vivo carcinogenicity.*