US regulation of GM foods differs fundamentally from the procedures adopted in the European Union.

Food agencies in the USA

Foods are regulated by three bodies in the United States of America. The US Food and Drug Administration (FDA) is concerned with food safety relating to new plant varieties, dairy products, seafood, food additives and processing aids, while the US Department of Agriculture regulates meat and poultry products as well as field testing of all genetically-modified plants. The US Environmental Protection Agency is responsible for 'pesticide chemicals' and it may therefore have to approve new plant varieties resistant to attack by pests. Of the three agencies, the policy of the FDA with respect to new plant varieties is most clearly defined at present.

Product, not process

The FDA regards the key factors in reviewing safety to be the characteristics of the food and its intended use, rather than the fact that new methods have been used in its production. This is a fundamental difference between the US regulations and those of the European Union, and lies at the root of much of the current controversy regarding GM foods.

Novel food products are not subject to special regulatory approval in the USA if the constituents of the food are the same or substantially similar to substances currently found in other foods (such as proteins, fats, oils and carbohydrates). For example, if a gene from a banana was transferred to a tomato, approval would not ordinarily be required before that food was placed on the market. However, if a sweetening agent that had never been an ingredient of any other food were added to a variety of grapefruit, then the novel food would need regulatory approval. The sweetener would be regarded as a 'food additive' and therefore be subject to other, more stringent, regulations.

Many GM foods in the USA are not subject to special regulation and they may not be segregated from non-modified foods. For commodity crops (such as soya and maize) imported into Europe, this can cause problems, since many such foods would have to be labelled under the EU novel foods regulation.

For imports into Europe, this problem has been resolved for maize and soya derived from GM plants by assuming that GM material will be present, unless the crop can be traced to a source which has been certified as free from GM material. The Ministry of Agriculture, Fisheries and Food in the UK (now replaced by the Food Standards Agency) prepared lists of such sources, so that food manufacturers may choose GM-free suppliers.

However, this is only a temporary solution to a problem which is certain to widen as more GM crops are cultivated.

US Agencies

US Department of Agriculture
Agricultural biotechnology Web site
http://www.usda.gov/agencies/biotech/index.html

US Environmental Protection Agency
http://www.epa.gov/oppt/biotech/index.html

US Food and Drug Administration
http://www.cfsan.fda.gov/~lrd/biotechm.html

The principle of substantial equivalence

The principle of 'substantial equivalence' is often raised in discussions of food biotechnology. 

It stems from a report of a working group established by the Organisation for Economic Co-operation and Development (OECD) of national experts to consider the safety implications of modern food biotechnology. The intention was to exchange ideas, data and information among experts to enhance international co-operation in this field. The working group considered numerous examples of how the safety of novel foods and food components had been evaluated in the past and established some concepts and principles that underpin the safety evaluation of foods derived by modern biotechnology. These principles have been widely accepted and are similar to recommendations made by other influential groups such as the World Health Organisation and the Food and Agriculture Organisation of the United Nations. The major conclusions of the OECD report are summarised below.

The report considered that the most practical method to establish food safety was to consider whether a novel food (or food component) was substantially equivalent to an analogous conventional food product, where one existed. Account should be taken of the processing (such as cooking) that the food may undergo, as well as how much food was to be consumed, by whom and the dietary pattern.

In demonstrating substantial equivalence, a number of factors have to be considered, such as:

• the characteristics and composition of the conventional food to which the new one is to be compared;
• knowledge of the component parts of the new product or organism, such as any introduced genes, the method used to introduce the new genetic material and how that new genetic material is expressed;
• the characteristics and composition of the new product or organism compared with the existing food or food component.

If the novel food is judged to be substantially equivalent to an existing food, then further safety or nutritional concerns are expected to be insignificant. Such foods are then treated in the same manner as their conventional counterparts. Where new classes of foods or food components are introduced it is more difficult to apply the concept of substantial equivalence. Here experience gained in the evaluation of similar materials is taken into account. Where a product is thought not to be substantially equivalent to an existing one, then further investigations, focusing on the identified differences are required. Totally new foods, where no similar materials have ever been consumed, must be evaluated solely on the basis of their own composition and properties.

Theoretical example: genetically-modified potatoes

As an example of the application of the principle of substantial equivalence, potatoes are an established part of the human diet. They can contain toxic alkaloids, but people generally know how to prepare them and avoid eating green potatoes which contain significant amounts of alkaloids. Potatoes are often infected by naturally-occurring viruses, but these do no harm to humans and have a long history of human consumption.

A potato that had been genetically-modified with one of these viruses so that it produced viral protein at levels comparable to those from naturally-infested potatoes would therefore be considered to be substantially equivalent to the infected potatoes that have a long history of safe use and consumption. This theoretical analysis applies only to viral proteins in the part of the potato plant that are traditionally consumed. It also assumes that the insertion of the viral coat protein gene does not lead to secondary effects through, for example, interruption of coding sequences within the plant's genome.

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