Gail Borden established strict sanitary requirements (the "Dairyman's Ten Commandments") To ensure against disease, for farmers who wanted to sell him raw milk: they were required to wash the cows' udders before milking, keep barns swept clean, and scald and dry their strainers morning and night
When returning from the London Exhibition to America in 1851 the shipboard cows on the vessel he traveled on both became infected with disease several children who drank the milk died and the the cows died also.
This is why he developed condensed milk to be a safe and long lasting milk that did not require refrigeration.