The risks from tainting or spoiling are particularly great in the case of milk, partly on account of the dusty and otherwise uncleanly barns and sheds in which it is often handled and kept, and from which it is loaded with a heavy crop of bacteria at the very start; and partly because the same delicateness which makes it so easily digestible for babies, makes it equally easy for germs and bacteria to grow in it and spoil, or sour, it. You all know how disagreeable the taste of spoiled milk is; and it is as dangerous as it is disagreeable. A very large share of the illnesses of babies and young children, particularly the diseases of stomach and bowels which are so common in hot weather, are due to the use of spoiled, dirty milk.
There is one sure preventive for all these dangers, and that is absolute cleanliness from cow to customer. All the changes that take place in milk are caused by germs of various sorts, usually floating in the air, that get into it. If the milk is so handled and protected, from cow to breakfast table, that these germs cannot get into it, it will remain sweet for several days. Boards of Health all over the world now are insisting upon absolutely clean barns and cleanly methods of handling, shipping, and selling milk. In most of our large cities, milk-men are not allowed to sell milk without a license; and this license is granted only after a thorough examination of their cattle, barns, and milk-houses. These clean methods of handling milk cost very little; they take only time and pains. (http://thehumanhealth.wordpress.com)
