Survey of Retail Milk Composition as Affected by Label Claims Regarding Farm-Management

A trend in food labeling is to make claims related to agricultural management, and this is occurring with dairy labels. A survey study was conducted to compare retail milk for quality (antibiotics and bacterial counts), nutritional value (fat, protein, and solids-not-fat), and hormonal composition (somatotropin, insulin-like growth factor-1 (IGF-1), estradiol, and progesterone) as affected by three label claims related to dairy-cow management: conventional, recombinant bovine somatotropin (rbST) free (processor-certified not from cows supplemented with rbST), or organic (follows US Department of Agriculture organic practices). Retail milk samples (n334) from 48 states were collected. Based on a statistical analysis that reflected the sampling schema and distributions appro- priate to the various response variables, minor differ- ences were observed for conventional, rbST-free, and or- ganic milk labels. Conventionally labeled milk had the lowest (P0.05) bacterial counts compared to either milk labeled rbST-free or organic; however, these differences were not biologically meaningful. In addition, convention- ally labeled milk had significantly less (P0.05) estradiol and progesterone than organic milk (4.97 vs 6.40 pg/mL and 12.0 vs 13.9 ng/mL, respectively). Milk labeled rbST- free had similar concentrations of progesterone vs con- ventional milk and similar concentrations of estradiol vs organic milk. Concentrations of IGF-1 in milk were sim- ilar between conventional milk and milk labeled rbST- free. Organic milk had less (P0.05) IGF-1 than either conventional or rbST-free milk (2.73 ng/mL vs 3.12 and 3.04 ng/mL, respectively). The macronutrient profiles of the different milks were similar, except for a slight in- crease in protein in organic milk (about 0.1% greater for organic compared to other milks). Label claims were not related to any meaningful differences in the milk compo- sitional variables measured. It is important for food and nutrition professionals to know that conventional, rbST- free, and organic milk are compositionally similar so they can serve as a key resource to consumers who are making milk purchase (and consumption) decisions in a market- place where there are misleading milk label claims. J Am Diet Assoc. 2008;108:1198-1203.