The Codex Alimentarius Commission—an obscure but important global food standards-setting entity—has been unable to adopt a residue standard for ractopamine, a drug used to promote rapid growth in pigs, cattle, and turkeys.

Proposed Maximum Residue Limits (MRLs) in beef and pork products have been stuck at the final step in the Codex process since 2008. (For the full companion story on the drug, see “Dispute Over Drug in Feed Limiting US Meat Exports”).

The current deadlock is unusual. The commission adopts dozens of food safety standards each year by consensus, with well over a hundred countries participating.

“Not only is it rare for a standard to be stuck at the final step at Codex, but it’s extremely rare for it to be this contentious,” said Michael Hansen, a senior scientist at Consumers Union, an advocacy group that has participated in the Codex meetings and has been vocal in its concern about the drug.

China and the European Union, which has 27 country votes at Codex, are vehemently opposed to adopting MRLs for ractopamine. They have so far managed to block repeated attempts by the U.S., Brazil, and others who use the drug in livestock production and want a standard adopted.

If a global standard were set, the United States could pursue trade actions against countries that ban meat produced with the drug, such as China, Taiwan, and the EU.

One of the commission’s scientific advisory panels — the Joint Expert Committee on Food Additives — ruled that ractopamine is safe and calculated acceptable MRLs: 10 parts per billion (ppb) in cuts like beef steaks and pork chops. That is below the 30 ppb for beef and 50 ppb for pork allowed by the U.S. Food and Drug Administration.

Based on meat consumption data, the Codex panel proposed higher global residue standards for organ meats, where the drug is found in higher concentrations.

Chinese scientists, who objected to the residue standards, were especially concerned because organ meats such as the lungs, liver, intestines and kidneys are more prevalent in the Chinese diet and thus people who ate them could face higher exposures to the drug.

In 2009, an independent panel of scientists at the European Food Safety Authority (EFSA) sharply questioned the Codex panel’s overall assessment in reaching a safety standard.

The 52-page EFSA report strongly criticized the data and methodology used by Codex to calculate the Acceptable Daily Intake, or ADI, for ractopamine. An ADI, along with data on how much meat consumers are likely to eat, allows the commission to set safe drug residue limits.

Codex used a human study sponsored by the drug maker Elanco to help calculate an ADI for ractopamine, but the EFSA panel concluded that the sample size was insufficient to draw conclusions about what level of ractopamine could be safely consumed by humans.

“If we cannot set an ADI, we cannot set a safe level for consumers,” said Claudia Roncancio-Peña, a scientist who led the EFSA panel.  “We need a more complete data set.”

The EFSA panel also questioned whether the Codex standards would adequately consider subpopulations, like pregnant women or people with heart conditions, who may be at higher risk when exposed to even traces of the drug.

Chinese officials are also sensitive about the issue, because the illegal use of growth-promoting drugs such as ractopamine—often called “lean meat powder”—on Chinese pig farms has sickened people, according to local press reports.

Though China has long banned the use of these drugs in livestock production, the government in December officially banned their production and sale, and

19 factories making “lean meat powder” were shut down, according to official Chinese media.