Sir; Mr Redfern (Letters, last week) protests too much. I hold no brief for biotech (or other) companies. It is axiomatic that all companies pursuing their businesses have vested interests. However, it is not the one-sided picture that the politicos of the organic field like to pretend. Organic food is big business, which is equally a vested interest; and the ideological anti-GM fundamentalists within the organic field have an additional vested interest in knocking GM. When bovine TB is again rearing its ugly head and the only safeguard for human health is milk pasteurisation, it is worth noting the arguments used by Redfern were precisely those used early in the previous century by the activists who tried to prevent the legalisation of milk pasteurisation ­ second only to clean water, the most important public health measure, which has saved untold lives. There have always been prophets of doom, Chicken Lickens crying out the sky is falling'. Instead, as a scientist Prof Chargaff ought to be lending his hand to the use of science to address the food supply needs of future generations. I would not want to have failure to do so on the conscience of his and my generation. Prof J Ralph Blanchfield Editor's note: Correspondence on this issue is now closed {{LETTERS }}