Effects of processing milk on concentrations of glucocorticoids in milk.

Concentrations of glucocorticoids were measured by protein binding in milk subjected to various processing methods. Raw whole milk was collected once per week for 3 wk from bulk milk tanks of each of 10 farms. Nine combinations of processing were tested: 1) none, 2) high-temperature short-time pasteurization of whole milk, 3) high-temperature short-time pasteurization and homogenization of whole milk, 4) bulk pasteurization of whole milk, 5) bulk pasteurization and homogenization of whole milk, 6) high-temperature short-time pasteurization of skim milk, 7) high-temperature short-time pasteurization and homogenization of skim milk, 8) bulk pasteurization of skim milk, and 9) bulk pasteurization and homogenization of skim milk. Mean concentrations of total glucocorticoids ranged from .46 to .65 ng/ml and were not different among either processing methods or whole versus skim milk classifications. No correlations were positive between percentage of fat and concentration of glucocorticoids in whole milk (-.22) or skim milk(-.09).