The battle between Monsanto, whose recombinant bovine somatatropin (rbST) growth hormone is sold under the Posilac name, and state legislators, farmers and food stores has spread to Ohio, where Cincinnati-based retailer Kroger wants to sell milk that is labeled as "hormone-free".
The problem for Kroger is that such labeling is technically illegal, since the official stance of the US Food and Drug Administration is that there is no difference between milk from cows that have or have not been given the hormone.
RbST helps cows produce milk for longer, and is marketed by Monsanto as a means of boosting milk production, a key advantage in a competitive US dairy market.
But producers who do not use the hormone also see a competitive advantage in labeling their milk as such, and in many cases have received the backing of retailers such as Kroger.
The Ohio-based store wants to sell milk carrying a label statement which claims that the milk does not contain the growth hormone, but was banned from doing so by the state governor.
Kroger's labels were also due to carry the statement that the FDA had found that rbST was safe - a compromise that has been permitted in other states such as Pennsylvania - but this system was considered inadequate because the FDA statement was in smaller print than the 'hormone-free' label.
The state's legislature will hold a hearing on the labeling issue next week.
Kroger announced last summer that it planned to sell only rbST-free milk by February 2008 because its customers did not want hormones in the milk they bought.
"Our customers' increasing interest in their health and wellness is the basis for our decision," said William Boehm, senior vice president and president of manufacturing for Kroger, back in August.
"We appreciate the willingness of dairy cooperatives across the country to work with us to make this transition in the next six months."
Monsanto executives did not respond to a request for comment prior to publication of this article.
But Monsanto believes that the attempts to label milk as hormone-free are not only illegal but also undermining the entire dairy industry, which has worked hard to sell itself as a producer of wholesome, nutritious and natural products.
"Some dairy food companies and retailers try to differentiate their products by asking coops and shippers to supply milk from cows not supplemented with Posilac," Monsanto's Kevin Holloway told a dairy industry conference back in 2006 - an indication of how long this issue has been rumbling on.
"This milk is positioned as a specialty product with labels that say things like 'no hormones or antibiotics', 'not produced with rbST' and a variety of other statements that imply it may be better than conventional milk."
"This undermines the industry's investment in positioning milk as a wholesome product since it raises the issue of 'good milk' versus 'bad milk'. This approach ignores the fact that milk is milk and there is no difference in the safety or quality of the product."
"The question we must answer as an industry is what impact does this have on consumer attitudes toward milk?"
The company was not immediately available for comment on the Kroger case.
The potential problem for Monsanto is that Kroger is not just a small wholefoods store or organic supermarket - it operates 2,458 supermarkets and multi-department stores in 31 states under two dozen local banners, as well as 779 convenience stores, and as such sells a vast quantity of milk.
Kroger will continue to sell the hormone-free milk regardless of whether it is allowed to label it as such, and should other major nationwide chains follow suit, Monsanto could find itself with increasingly diminishing numbers of buyers for Prosilac, at least in the US, as farmers could be obliged to make the hormone-free pledge in order to sell their milk.
Furthermore, Kroger's argument is compelling - consumers simply do not want to drink milk with hormones (at least, Kroger's customers do not want that) and most shoppers do not care whether the FDA thinks the hormone is safe or not - they would simply rather not have it.
Monsanto claims that using Prosilac is beneficial to consumers because it "helps produce high-quality milk while using fewer resources and generating less waste per gallon of milk produced" and that "consumers benefit with rbST use due to the availability of more milk at lower prices".
And it argues that "while some surveys reveal strong consumer resistance to rbST, others indicate confidence in the US milk supply, and no substantial intent to forego use of rbST milk".
Kroger however, is gearing up for a labeling fight in at least another 30 states.