US fastfood chain McDonald’s will reportedly direct some meat suppliers to stop using antibiotic growth promoters and encourage others to cut back.

The policy, which comes in response to warnings that widespread use of antibiotics on US farms is decreasing their effectiveness in human medicine, will focus on the use of antibiotics in animal feed to speed the development of livestock, reported the Washington Post.

As McDonald’s is the largest purchaser of beef in the US and among the largest for chicken and pork, the move should have a noticeable effect on the amount of antibiotics used as growth promoters.

“This is a highly significant policy and change,” Rebecca Goldburg of Environmental Defense, an advocacy group that participated in McDonald’s review of its practices, was quoted by the Post as saying. “This policy is global and it goes beyond anything we have seen from other companies.”

The policy will prohibit McDonald’s direct suppliers, which mainly supply chicken, from using 24 growth promoters that are closely related to antibiotics used in human medicine. It will be effective worldwide by the end of 2004 and will require suppliers to keep records and agree to regular audits.