Food Safety Evaluation Evaluating Safety: A Major Undertaking

Foods made from GMOs must be considered safe – otherwise they wouldn’t have received authorisation. But assessing safety is easier said than done.

Like any food, genetically modified or other novel foods are complex mixtures of thousands of different substances in varying proportions. With trusted foods that have been eaten for generations there is little concern. They are considered safe based on experience, not necessarily based on scientific proof.

For novel or genetically modified foods, proving safety is a legal obligation. This burden of proof is often a high hurdle to leap.

Safety evaluation in two steps

According to laws that apply to all EU member states, a GM food can only be allowed onto the market if it can be documented using scientific data that it is just as safe and healthy as a comparable conventional product.

When evaluating the safety of food from a genetically modified organism, two areas are looked at in particular:

(1) The safety of the novel GM trait

When a new gene is introduced into a plant, the general outcome is the formation of a new protein. These proteins are oftentimes new for human consumption. Effects on human health are not out of the question.

The safety of a particular protein regarding toxicity is assessed using animal feeding tests. For food additives or herbicide residues, these kinds of tests are routine. When results from animal trials are applied to humans, considerable extra safety measures must be taken.

Safety evaluations must include tests to find out if the new protein could trigger allergies. Several criteria are known that suggest allergenic potential. If one or more of these criteria are met, the GM plant expressing this protein is unlikely to receive clearance in the EU.

(2) Unforeseen changes in plant metabolism as a result of gene transfer

When a new gene is transferred to a plant, no one can automatically rule out the possibility of unforeseen "side effects". This has to do with the fact that a new gene can interact with existing genes. For instance, a new gene could deactivate an existing gene, thereby causing shifts in a plant’s metabolism. In certain cases, this kind of change could potentially impact human health.

To see what types of unforeseen changes may have taken place, two types of tests are carried out: an analysis of the most important chemical components of the GM plant and animal feeding trials.

Chromatography Individual compounds in a GM plant are made visible Feeding test: Laboratory rat

Chemical analyses In order to minimize the possibility of harmful, unforeseen effects, genetically modified plants and derived foods are subjected to thorough analyses. Nutritional value and vitamin content are measured along with levels of toxins that occur naturally in some foods. An increase in toxin content to unsafe levels is not permissible. If any other measurements are different from the plant’s conventional counterpart, it would suggest that problematic, unintended effects could exist. The health consequences of such differences would need to be thoroughly investigated. Feeding tests In many cases, feeding test results are submitted to authorities along with an application for the authorisation of a product in the EU. In these tests, the whole food is fed to animals such as rats or chickens over an extended period of time. It is anticipated that any dangerous "side effects" of the GM food would be made noticeable by changes affecting, for instance, the animal’s immune system or its internal organs.

Feeding tests: Common practice

Toxicological assessments on test animals are not explicitly required for the approval of a new food in the EU or the US. Independent experts have decided that in some cases, chemical analyses of the food’s makeup are enough to indicate that the new GMO is substantially equivalent to its traditional counterpart. Feeding tests are only requested in cases of doubt.

Nonetheless, the results of animal tests are routinely presented to the European safety assessment authorities. In recent years, biotech companies have tested their transgenic products (maize, soy, tomato) before introducing them to the market on several different animals over the course of up to 90 days. Negative effects have not yet been observed.

GMO critics claim that feeding studies with authorised GMOs have revealed negative health effects. Such claims have not been based on peer-reviewed, scientifically accepted evaluations. If reliable, scientific studies were to indicate any type of health risk, the respective GMO would not receive authorisation.

See also on GMO-Compass:

• Food Safety Evaluation: The allergy check