Page:The story of milk.djvu/173

 eaten with cereals, berries, etc. In twelve hours most of the cream will rise and may be skimmed off, although thirty-six or even forty-eight hours may be required to get all that can be obtained by setting. The half-skimmed milk left when the top-milk has been removed after 3 to 6 hours' setting will still contain 2% or more of butter-fat and is very good for drinking; even the skim milk from which the cream has been taken after 12 hours' setting is still an excellent beverage, provided it is sweet. Perfectly skimmed, almost entirely fatless, milk may be used in various ways in cooking, to make up for lack of protein in many other food products. But care must be taken that it is pure and sweet, or rather, its condition, sweet or sour, must be under the perfect control of the housekeeper. If a sample of milk will stand scalding or even boiling without curdling, it is usually fresh and in good condition for any use. On the other hand, if it curdles by scalding, it is beyond control and it may or may not make good sour milk, depending on the bacteria working in it.