The blame lies with a poultry feed additive Roxarsone, developed in the 1940s to combat parasites in chickens, but with the added benefit of being a growth enhancer and adding a “fresh” colour to the meat.
Now a report from the US Food and Drug Administration (FDA) has admitted that the additive – which contains arsenic – has been leaching the cancer-causing toxin into the meat. It will now be banned as a carcinogen.
Until the publication of the report, the FDA and the poultry industry had vehemently denied that Roxarsone passes into meat destined for human consumption. But in a study of 100 chickens, those that had eaten it were found to have higher levels of inorganic arsenic, which is more toxic than naturally occurring arsenic.
Marketed as 3-Nitro by Alpharma LLC, a subsidiary of pharmaceutical giant Pfizer, the company has agreed to pull feed containing Roxarsone it from shelves in the US next month. However, it has said it will not do so in other countries unless regulators force it to do so.
The FDA refused to advise people to stop eating chicken, as it claims the meat of chickens reared on the Roxarsone-containing feed contains only minute traces of arsenic. The study revealed “concerns of a very low but completely avoidable exposure to a carcinogen,” said FDA deputy commissioner Michael Taylor.
Explaining why the drug was licensed in the first place, the FDA said the expectation had been that the arsenic would pass through the chicken and not into its meat:
“The scientific understanding at the time of approval was that the organic arsenic in 3-Nitro® (Roxarsone) would be excreted as organic arsenic, which is not known to be a carcinogen. Until recently, scientific evidence indicated that animals exposed to organic arsenic rapidly excrete the compound in its original form — as organic arsenic. FDA approved the product at doses and withdrawal times that, based on this available information, allowed for the safe and effective use of the product when used according to the label directions.”