4 Assessing the safety of GM food
Pusztai and his team were attempting to develop suitable tests to assess the safety of GM potatoes. Typically, testing the safety of GM food involves comparing its composition and/or its effects with that of the conventionally produced food it most closely resembles. We have seen that such comparisons were at the heart of Pusztai's work.
The comparison of GM and conventional crops and food has led to the so-called principle of substantial equivalence, which has been used extensively by regulatory authorities. If a GM plant, or food derived from it, is regarded as substantially equivalent to its conventional equivalent, it is assumed that no new health risks are presented, thus paving the way for commercial development.
Some see the operation of this principle as the abandonment of the need for careful safety tests, on the grounds that the GM product is automatically assumed to be essentially identical to 'tried and tested' products. Pusztai was particularly dismissive of the principle. A major motivation of his work on GM potatoes was a desire to develop more rigorous testing regimes. We will spend some time examining how interpretations of this principle have changed over time, and some of the controversy that has surrounded the term. In doing so, we would hope that you gain insight into the way that the scientific assessment of risk influences regulatory decision making, nationally and internationally.