Whilst the horsemeat contamination undermined consumer confidence in the global food chain it was generally agreed this was not a safety issue.

The pragmatic reporting threshold of 1% for horsemeat contamination set by the UK Food Standards Agency (FSA) reflects the level of adventitious or accidental contamination that may be accepted as not necessarily equating to a breach of regulatory requirements. (Please click here for details.)

However, there is no comparable de minimis threshold level for phenylbutazone or 'bute': This is an anti-inflammatory drug most commonly used as a medicine in horses. As technology develops ever greater sensitivity in testing sometimes contaminants are identified in 'parts per million' (ppm) or even 'parts per billion' (ppb), and in these trace amounts a specific risk assessment on that particular product might conclude that there would be no realistic safety implication to the consumer.

For example, Chief Medical Officer, Professor Dame Sally Davies, has been reported by the FSA as explaining: 'Horse meat containing phenylbutazone presents a very low risk to human health. Phenylbutazone, known as bute, is a commonly used medicine in horses. It is also prescribed to some patients who are suffering from a severe form of arthritis. The levels of bute that have previously been found in horse carcasses [the highest level for this being 1900ppb] mean that a person would have to eat 500 - 600 one hundred per cent horsemeat burgers a day to get close to consuming a human's daily dose. And it passes through the system fairly quickly, so it is unlikely to build up in our bodies. In patients who have been taking phenylbutazone as a medicine there can be serious side effects but these are rare. It is extremely unlikely that anyone who has eaten horse meat containing bute will experience one of these side effects.'

In the current situation, despite extensive testing, the FSA has found no bute in any of its' food samples, 14 horses were prevented from entering the food chain and separate extensive industry testing has found only one example of trace amounts of bute; (4 parts per billion in Asda corned beef that resulted in a recall in April.)

Clearly there is a quality and regulatory concern about the presence of any illegal contamination, but it is arguable that it is now time to accept that such rare and trace levels of bute do not constitute a realistic safety risk to be prioritised by the FSA on the scale currently being seen.