Cholov Yisroel this

Ben Chorin: I don�t generally stay up all night for tikkun leil hoshanah rabba:

Anyhow, the torah I want to discuss involves a practical question that an old friend tells me has been troubling a prominent talmid chakham in the U.S. It seems that there is a well-established statistical rule that some non-negligible fixed percentage (let�s say 10%) of milking cows turn out to be treifos, though at the milking stage we have no way of knowing whether a given cow is one of the treifos or not. In any given randomly selected large herd of cows it is very likely that the percentage of treifos is close to 10%. The combined milk of the herd therefore includes a high proportion of non-kosher milk, certainly well in excess of 1/60. Should industrial milk therefore be ruled non-kosher?

See also description of milk manufacturing under Dirty Secrets of the Food Processing Industry.