South Korea plans to lift the ban on the use of zilpaterol, also known as Zilmax as marketed by Merck Animal Health, by early 2014, thus permitting the import of US beef containing the growth enhancer, according to a senior food ministry official.
The latest development also came as US drugmaker, Merck & Co, reportedly announced its decision to resume sales of the controversial Zilmax feed additive, which is also a zilpaterol drug, in the US and Canada following an audit on the product's application. A date for the resumption of sales has not been confirmed.
South Korea's zero tolerance policy on zilpaterol-based drugs has caused the suspension of some US beef imports during October 2013 after traces of the feed additive were found in two shipments.
However, the government's recent risk assessment found that the feed additive could be permitted at certain levels, said Son Seong-wan, director of livestock products standard division at South Korea's food ministry. The assessment was conducted at the request of Merck's subsidiary, MSD Animal Health Korea.
"Once the level tolerated is established early next year, domestic sales of Zilmax will be possible immediately," he added. Seong-wan declined to specify the permitted level, but said that the food ministry was waiting international recommendations on zilpaterol due to be released soon by a Joint FAO/WHO Expert Committee on Food Additives (JECFA).
According to the director and an official at MSD Animal Health Korea, the US allows 12 parts per billion (ppb) of zilpaterol in beef liver, while Japan permits 10 ppb in beef muscle.
Merck had stopped the sale of Zilmax in August 2013 after Tyson Foods Inc announced that it would stop accepting Zilmax-fed beef when cattle for slaughter were alleged to experience movement difficulties. Cargill Inc, one of the world's largest beef processors, followed suit, banning the use of the feed additive on processed beef and cattle in the company's feedlots. The company will be committed to the current course of action until Asian countries and other trading partners are able accept such beef products in their markets.
The Zilmax suspension also led feedlots to turn to Optaflexx, which is manufactured by Elanco and also known as ractopamine.
Zilpaterol has been placed under global scrutiny after a video emerged in the US in August this year, showing animals struggling to walk and displaying other signs of distress upon taking a growth drug.
Although Zilmax was approved by the US Food and Drug Administration in 2006, South Korea, along with other Asian countries including China, has not approved zilpaterol for use in meat. Many European countries have also banned the import of zilpaterol-fed beef due to concerns about the side effects of additives.
The beta-agonist drug has been reportedly used in cattle feeding at several US feedlots for more than five years. "Beta-agonists increase the deposition of lean muscle on the carcass. They make cattle more efficient at converting grain to muscle," explains Chris Reinhardt, an extension feedlot specialist for K-State Research and Extension, during a recent interview. "They also help the efficiency of converting an animal carcass into sellable meat."
The restriction on zilpaterol usage means that cattle carcass weights are on the decline even as feedlots rush to cash in on record-high prices, said analysts and economists. A combination of lower beef production and cattle numbers are expected to push up prices through the coming year.
Reinhardt had downplayed concerns that Zilmax may have an adverse effect on cattle mobility, listing hot summer conditions, among other factors, as a possible cause. According to the specialist, there is no direct link between the use of the beta agonist and weakened animal movements.
