"Many yeast strains are being engineered to have a higher metabolism and as a result, enhanced fermentation properties in processes such as bread baking and beer production. However, an investigation of GE yeast containing extra copies of genes involved in the metabolism of glucose, found that they also accumulate a highly toxic and mutagenic substance known as methylglyoxal. The authors of this study warn that careful thought should be given to the nature and safety of metabolic products when GE yeast are used in food-related fermentation processes especially since current risk assessments based upon the principle of substantial equivalence are unlikely to detect any harmful substances.
The inadequacy of substantial equivalence
"(This example) illustrates the fact that a product derived from a GE organism (bacteria, yeast or plant), can be devoid of genetic material but can still unexpectedly contain potentially harmful alterations to a GE product, a novel toxin or elevated levels of a known hazardous substance. The current systems for assessing the health risks of GE foods do not appear to have fully taken into account this unpredictability of genetic engineering technology. At present it is only required that the amounts of a few known components (nutrients, allergens and natural toxins) be measured in order for substantial equivalence to be established.
When viewed from a fundamental genetics standpoint, the manner in which the principle of substantial equivalence is being applied would appear to be conceptually flawed. Since genetic engineering has the potential to unexpectedly produce novel toxins and allergens, the assessment of only known constituents is insufficient. This problem is further compounded by the fact that each analytical technique that is used possesses it's own limitations. Unless one fortuitously chose an analytical method that happened to detect a novel compound in the GE food, it can quite easily be missed even if present in abundance. As a result, since one cannot specifically test for an unknown health hazard, it is clear that only by applying pharmacological-type toxicity testing can the risks of GE foods be adequately assessed.
If a new drug is produced via genetically engineered organisms then it must quite rightly go through pre-clinical tests in animals to assess acute toxicity and, more importantly, extensive clinical trials in human volunteers to not only determine efficacy, but also to detect any unexpected effects of the product including unknown toxins resulting from the production process. Given that the same imprecise technology is used to produce GE foods in general then surely the same rules should apply for both. Clearly a double standards situation exists which needs rectifying.
Pharmacological toxicity testing is designed to assess adverse effects of a product in a very general manner regardless of whether it is a single substance or a complex mixture and can therefore equally be applied to GE foods as well as drugs".
Ref: Genetic Pollution; Nutritional Therapy Today (1996); Dr Michael Antoniou, Senior Lecturer in Molecular Pathology, London, UK

[From List: Biotech Activists (biotech_activists@iatp.org) Date Posted: 11/06/1999 Posted by: RBBAX@aol.com]

A drastic example of how seriously flawed scientists may become is illustrated by the decision to accept the principle of "Substantial Equivalence" for the assessment of the safety of Genetically Engineered foods. In brief, the principle means that if a genetically engineered food appears to be similar to its natural counterpart it can be assumed to be as safe as the natural variety.

The concept of "Substantial equivalence" was invented by lawyers working for the Biotech industry with the openly declared purpose of facilitating rapid approval of GE foods in the US. It has no tenable scientific basis, as explained in the document "Substantial equivalence versus scientific food safety assessment". In spite of its obvious lack of scientific backing it was officially supported by scientific expert committees for food safety appointed by the United Nation organ FAO, as well as by the European Union (EU) and the United States. Governments consequently adopted it and integrated it into their laws for regulating GE foods.

"Substantially equivalent" foods were allowed by law to be put onto the market without any thorough testing of their safety, although it has been established in the laboratory that GE may induce the appearance of unexpected and potentially harmful substances (see "The safety of GE foods").