An increasing number of dairy companies, hoping to cash in on the popularity of natural foods, are selling milk that is not organic, but is free of the genetically engineered growth hormone rBST, also called Posilac.
The hormone-free milk costs more than regular milk, but less than organic milk, which requires greater expense and special feeds for the cows.
rBST increases the amount of milk cows produce, but it can result in cows being treated with extra antibiotics due to udder inflammation, and can produce milk with higher amounts of a different hormone, insulin-like growth factor 1, which has been linked to cancer. Many buy organic milk solely to avoid the hormone.
However, as a result of a lawsuit by Monsanto, the manufacturer of Posilac, the FDA mandates that hormone-free milk carry a label stating that no difference has been found between milk from treated cows and milk from untreated cows.