Toxicological Evaluation of Biotechnology Food Products

Abstract

Biotechnology enables preparation of a diverse range of products, which may be end products for the user or processing agents. Toxicological evaluation requires greater attention to some potentially harmful properties, but does not differ in essentials from standard considerations and test requirements. Products of biotechnological processing may be considered in terms of (a) examination for potential hazards for the products' user, (b) protection of the environment from contamination by organisms derived by genetic engineering, and (c) public emotional responses to biotechnological products and processes. This presentation is mainly concerned with the first issue. Examination for potential hazards requires consideration of the product-forming microorganisms, whether or not the product is the recipient of genes derived from other organisms. If gene transfer has been made, detailed information is required on the identity of the gene, identity and properties of the source and recipient organisms, and transfer of the expression vector into the host. The examination of the fermentor product will be considered in detail, particularly with reference to the detection of any unknown toxins and potential mutagens. First considerations are the stability of the organisms used, and the identity and purity of the gene product. Subsequent examination for mutagenic activity depends upon compatibility with in oifro assay. These include bacterial mutation, primary rat heptocytes (toxicity, DNA repair, inhibition of protein synthesis) and Chinese hamster V79 cells (toxicity and cytogenetics). Parallel tests may be made of digests of food products. If the test product is not compatible with in oifro assays, in uioo tests for micronucleus formation, metaphase chromosome analysis and DNA repair are available as substitutes. Apart from this screen for mutagenic activity, additional tests follow standard procedures for safe handling and feeding tests, pharmacokinetics and teratology, all supported by full pathology.The three main considerations in toxicological evaluation of products or processing aids derived from microorganisms are the properties of the source organism, the safety of any processing aid, e. g. enzyme, and the safety and acceptability of the final product. A scheme is presented of the bio-assays used to determine that microbial enzymes are free from unknown toxins, or toxins possibly escaping from chemical analysis.A representative production batch which becomes the model to set a product specification, is subject to very critical examination. Much less is required to monitor routine production batches. The representative enzyme batch is first examined by chemical analysis for likely mycotoxins. Then samples are prepared as crude solutions in appropriate media (JYMSO or culture media). Further samples are extracted in water/chloroform, evaporated to dryness, and the partially purified, concentrated extract is dissolved in media. The crude solution and concentrated extract are examined on four strains of salmonella in t...