In the early-to mid 1990s, with the development and commercialisation of genetically modified food becoming an imminent possibility, national and international authorities began to consider a suitable regulatory framework for the new technologies. The "substantial equivalence" approach was eventually adopted. The exact definition of "substantial equivalence" in this context is hard to pin-down and this has led to several conflicting interpretations.

Initially, it was thought that if a genetically modified food was "substantially equivalent" to its traditional counterpart, a risk assessment would not be neccessary. The test compared attributes such as protein, carbohydrate and fatty acid levels between the novel food and its traditional counterpart. However, there were no clear and universal guidelines stipulating what to test and how similar the items in question should be. It has been said that the amount of comparative data required to establish "substantial equivalence" involved "a somewhat subjective judgement" (Royal Society 2002: 5-6).

So, the approach proved immensely controversial. Consumer organisations, environmental groups and a few leading scientists criticised "substantial equivalence" for helping to play down the novelty of genetic engineering and facilitating its commercialisation. Over the years, the approach has come to mean something very different and has ultimately been demoted to a regulatory tool - albeit implicitly.

Europe and the United States currently differ in their implementation of "substantial equivalence". In Europe, the capability to classify a novel food as being "substantially equivalent" no longer justifies a lack of safety assessments. The European regulatory process now places much more emphasis on identifying the unintended consequences of genetic modification. Moves are being made to develop better methods for testing composition, metabolic activity, toxicity, allergenicity, etc. Presently, the official European consensus is that "substantial equivalence" should only be used to guide or inform safety assessments. It should be seen as a starting point in the regulatory process rather than an end point. However, in the United States "substantial equivalence" still plays a significant (if slightly diminished) role in the regulation and commercialisation of genetically modified foods.

See also

• risk management

Bibliography

• Royal Society (2002) Genetically Modified Plants for Food Use and Human Health.