i don't know how you deal with it in the uk but here we track our cows meticulously. farmers can generally tell if a cow is sick and will milk her into the drain but even if he doesn't, every day the milk tanker comes and he'll take a sample with him. if your milk is contaminated then they'll dump the full 40 tonnes of milk down the drain and make the farmer pay for it. it obviously still happens occasionally but then i've been asked to throw out chocolate due to e. coli contamination. i won't argue against your personal preferences. i'm only against the law that prohibits me from buying raw milk at the same store where i can buy eggs and spinach caked in bird shit and steak tartare.
Denmark