Study: Organic, rbST-Free Milk Same as Conventional

ITHACA, N.Y.Researchers at Cornell University reported no meaningful nutritional differences between conventionally produced milk with no specialty labeling, milk labeled rbST-free and milk labeled organic in a recent Journal of Dairy Science-published study (Volume 93, Issue 5, Pages 1918-1925 (May 2010)). They all milks were similar in nutritional quality and wholesomeness.

They did find differences in fatty acid composition with organic milk, however. Organic milk was higher in omega-3s and saturated fat, and lower in monounsaturated fat, polyunsaturated fat and trans fat. Regarding the fat content, researchers said, From a public health perspective, the direction for some of these differences would be considered desirable and for others would be considered undesirable; however, without exception, the magnitudes of the differences in milk fatty acid composition among milk label types were minor and of no physiological importance when considering public health or dietary recommendations.

They investigated nutritional differences in specialty labeled milk, specifically to compare the fatty acid (FA) composition of conventional milk with milk labeled as recombinant bST (rbST)-free or organic. The retail milk samples (n=292) obtained from the 48 contiguous states of the United States represented the consumer supply of pasteurized, homogenized milk of three milk types: conventionally produced milk with no specialty labeling, milk labeled rbST-free,and milk labeled organic.

No statistical differences in the FA composition of conventional and rbST-free milk were found; however, these two groups were statistically different from organic milk for several FA. When measuring FA as a percentage of total FA, organic milk was higher in saturated FA (65.9 vs. 62.8 percent) and lower in monounsaturated FA (26.8 vs. 29.7 percent) and polyunsaturated FA (4.3 vs. 4.8 percent) compared with the average of conventional and rbST-free retail milk samples. Likewise, among bioactive FA compared as a percentage of total FA, organic milk was slightly lower in trans 18:1 FA (2.8 vs. 3.1 percent) and higher in omega-3 FA (0.82 vs. 0.50 percent) and conjugated linoleic acid (0.70 vs. 0.57 percent).

It should be noted the study was supported in part by the Monsanto Company; Cornell Agricultural Experiment Station; and the Cooperative State Research, Education, and Extension Service, USDA.