Letter: Food of the future

Sir: As a scientist working in biology and medical research, I am very aware of the limitations of molecular biology. The techniques are very powerful and it is relatively easy to show that the desired aim of a genetic modification experiment has been achieved - ie a foreign protein is expressed in a cell.

However, it is almost impossible to predict deleterious effects of the the procedure and therefore to show that a modified plant is safe to eat in large quantities over many years. The evaluation of safety will of necessity also take many years.

Until we have completed extensive trials, GM foodstuffs should not be used in animal foods or mixed with other foods. Any GM product should be clearly labelled.

Faced with the risk that BSE may be transmitted through blood donation, the US government is considering barring blood donation by US citizens who have visited the UK since the BSE outbreak. Faced with much greater potential risks, we should surely be banning the import or production of GM crops.

Dr MARK WORWOOD

Cardiff