Unsafe genetically modified foods may soon find their way into shops, Philip James, the man behind the Food Standards Agency, warned MPs this week. Here, he and Andrew Chesson argue that a flood of unique GM foods is about to overwhelm the regulatory safety net and that Britain must revamp it if lives are not to be put at risk

The recent media frenzy about the supposed toxic effects of genetically modified plants has astonished scientists everywhere. The US is bewildered by the "irrational" response of Europeans and other un-enterprising groups abroad. Europeans, however, are determined to take the precautionary approach when dealing with food safety.

Since the second world war people have been losing control of their food supply. Europeans now worry that they could be seriously affected by industrial or political pressures on scientific groups that meet in secret.These groups may make mistakes similar to those that exposed millions to BSE, or mad cow disease.

We are not concerned about the safety of the four genetically modified foods on sale in British supermarkets - they have gone through exhaustive scrutiny over a decade. Now, however, a different challenge is upon us because literally hundreds of genes are being inserted into plants in field trials.

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In the US, field trials of 56 different plant species that have been genetically manipulated are complete; there have been 450 trials of 32 different genetic traits inserted into potatoes alone over an eight-year period. So the issue is how to assess the very different types of genes being transferred into crops and how our regulatory system can cope with the huge impending demands from scientists and companies that new GM foods and crops be cleared for sale to the public.

Already the scientific excitement and huge investments have led to new procedures. In Europe a country must decide within 90 days if a novel food or crop should be cleared. Any further scrutiny by other countries must be completed within 60 days.

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If one European country disagrees with the decision of another about whether or not a GM food should be approved for sale, the European Commission will refer the dispute to its new independent scientific committee in the consumer health protection directorate, DGXXIV. If EU and US regulatory authorities disagree, disputes are referred by the World Trade Organisation to the Codex Alimentarius Commission, which answers to the World Health Organisation/Food and Agriculture Organisation.

But Codex is dominated by food-industry interests, particularly North American food industries. Half of the world's ministries of health do not bother to attend, and there is little public interest, consumer or third world involvement. Within such a framework, there is a strong possibility that major trade disputes on GM foods could arise.

We also believe that the approach to assessing the safety of genetically modified crops in North America is not safe enough for the future. For instance, one of the issues in establishing the safety of GM foods is the ability of the digestive tract to digest the protein encoded by the transgene. Tests approved by the US FDA assume that everyone has a healthy intestine able to produce stomach acid - but the very young and very old often do not.

Likewise, the FDA's "accepted" practice of testing the protein from a gene inserted into a bacterium rather than into the plant itself neglects the fact that the protein may be modified differently when it is in a plant.

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A third issue relates to the so-called "substantial equivalence" of a transgene. Conventionally, this is established by comparing the composition of the transgenic plant with that of its original, unmodified parent. But present data are crude, and only when obvious natural toxicants might occur, eg glycoalkaloids in potato or glucosinolates in brassicas, are they monitored. Routine procedures are unlikely to detect new toxic metabolites accumulating because the insertion of a new gene has silenced an existing plant gene and disrupted a metabolic pathway.

We suggest that a host of new technical approaches should be adopted by governments seeking to ensure the safety of genetically modified food to keep pace with the remarkable developments in plant genetic engineering.

But what consumers really worry about is how to make sure that GM crops are not mixed with unmodified foods. With hundreds of genetic changes planned over the next five to ten years, we very much doubt that the distinction between modified and unmodified foods can be maintained.

From a scientific point of view it is far more important to ensure an effective regulatory system than to try to separate GM crops from the general food supply.

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This is a real opportunity for the UK to take the lead and win the scientific arguments both in Europe and in the WTO negotiations. Public confidence through effective initiatives to safeguard public health will do more for the development of the biotechnological revolution than continuing the debate about the risks and benefits of GMOs.

Philip James is director of the Rowett Research Institute, Aberdeen. Andrew Chesson of the RRI is on the European Union's GMO committee.

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