General Mills is to eliminate milk sourced from cows treated with rBST (recombinant bovine somatotropin), a synthetic hormone in the production of its category-leading Yoplait yogurts.

The company said it will have eliminated rBST, also referred to as rBGH, by August 2009.

General Mills said that, authorities, including the US Food and Drug Administration (FDA), remain fully confident in the safety of products made from milk sourced from cows treated with rBST, it wanted to provide consumers with the "option to choose a category-leading yogurt with milk produced by cows not treated with rBST."

"We estimate that more than 70% of our milk is already coming from cows that are not treated with rBST," said Becky O'Grady, General Mills' vice president of marketing for the Yoplait brand. "We are committed to reaching 100% no later than August."

She went on: "General Mills and Yoplait strive to offer only the highest quality products to consumers. While the safety of milk from cows treated with rBST is not at issue, our consumers were expressing a preference for milk from cows not treated with rBST and we responded."

Approved by the FDA in 1993, rBST is considered chemically identical to naturally occurring bovine hormones.

So-called 'rBST-free' milk is more difficult to source, General Mills said, but it was making the switch to 'rBST-free' milk nonetheless.