Part 42 (1/2)

In was.h.i.+ng milk dishes, many persons put them first into scalding water, by which means the alb.u.men in the milk is coagulated; and if there are any crevices or seams in the pans or pails, this coagulated portion is likely to adhere to them like glue, and becoming sour, will form the nucleus for spoiling the next milk put into them. A better way is first to rinse each separately in cold water, not pouring the water from one pan to another, until there is not the slightest milky appearance in the water, then wash in warm suds, or water containing sal-soda, and afterward scald thoroughly; wipe perfectly dry, and place if possible where the sun will have free access to them until they are needed for further use. If suns.h.i.+ne is out of the question, invert the pans or cans over the stove, or place for a few moments in a hot oven.

The treatment of milk varies with its intended use, whether whole or separated from the cream.

Cream rises best when the milk is quite warm or when near the freezing-point. In fact, cream separates more easily from milk at the freezing-point than any other, but it is not thick and never becomes so.

An intermediate state seems to be unfavorable to a full rising of the cream.

A temperature of 56 to 60F. is a good one. Milk to be used whole should be kept at about 45 and stirred frequently.

All milk obtained from city milkmen or any source not certainly known to be free from disease-germs, should be sterilized before using. Indeed, it is safest always to sterilize milk before using, since during the milking or in subsequent handling and transportation it is liable to become infected with germs.

TO STERILIZE MILK FOR IMMEDIATE USE.--Put the milk as soon as received into the inner dish of a double boiler, the outer vessel of which should be filled with boiling water. Cover and heat the milk rapidly to as near the boiling point as possible. Allow it to remain with the water in the outer boiler actively boiling for half an hour, then remove from the stove and cool very quickly. This may be accomplished by pouring into shallow dishes, and placing these in cold water, changing the water as frequently as it becomes warm, or by using pieces of ice in the water. It is especially important to remember that the temperature of the milk should be raised as rapidly as possible, and when the milk is sufficiently cooked, cooled very quickly. Either very slow heating or slow cooling may prove disastrous, even when every other precaution is taken.

Or, well-cleaned gla.s.s fruit cans may be nearly filled with milk, the covers screwed on loosely, then placed in a kettle of cold water, gradually heated to boiling and kept at that temperature for a half hour or longer, then gradually cooled. Or, perfectly clean bottles may be filled with milk to within two inches of the top, the neck tightly closed with a wad of cotton, and the bottles placed in a steam cooker, the water in which should be cold at the start, and steamed for half an hour.

This cooking of milk, while it destroys many of the germs contained in milk, particularly the active disease-germs which are liable to be found in it, thus rendering it more wholesome, and improving its keeping qualities somewhat, does not so completely sterilize the milk that it will not undergo fermentative changes. Under varying conditions some thirty or forty different species of germs are to be found in milk, some of which require to be subjected to a temperature above that of boiling water, in order to destroy them. The keeping quality of the milk may be increased by reboiling it on three successive days for a half hour or longer, and carefully sealing after each boiling.

TO STERILIZE MILK TO KEEP.--This is a somewhat more difficult operation, but it may be done by boiling milk sealed in very strong bottles in a saturated solution of salt. The milk used should be perfectly fresh. It is best, when possible, to draw the milk from the cow directly into the bottles. Fill the bottles to within two inches of the top, cork them immediately and wire the corks down firmly and place them in the cold salt solution. Boil fifteen minutes or half an hour.

Allow the solution to cool before removing them. If the bottles are removed from the solution while hot, they will almost instantly break.

When cold, remove the bottles, and cover the tops with sealing wax.

Store in a cool place, shake thoroughly once or twice a week. Milk sterilized in this manner will keep indefinitely.

CONDENSED MILK.--Condensed milk is made by evaporating milk in a vacuum to one fifth its original volume; it is then canned like any other food by sealing at boiling temperature in air-tight cans. When used, it should be diluted with five times its bulk of warm water.

Condensed milk, when not thoroughly boiled in the process of condensation, is liable to harbor disease-germs the same as any other milk.

CREAM.

Cream varies in composition according to the circ.u.mstances under which it rises.

The composition of an average specimen as given by Letherby is:--

Nitrogenous matter............................................ 2.7 Fat.......................................................... 26.7 Sugar of milk................................................. 2.8 Mineral matter................................................ 1.8 Water........................................................ 66.0

In the process of churning; the membranes of casein which surround each of the little globules const.i.tuting the cream are broken, and the fat of which they are composed becomes a compact ma.s.s known as b.u.t.ter. The watery looking residue containing casein, sugar of milk, mineral matter, and a small proportion of fat, comprises the b.u.t.termilk.

Skim-milk, or milk from which the cream has been removed, and b.u.t.termilk are a.n.a.logous in chemical composition.

The composition of each, according to Dr. Edward Smith, is:--

SKIM-MILK

Nitrogenous matter......................................... 4.0 Sugar...................................................... 3.8 Fat........................................................ 1.8 Mineral matter............................................. 0.8 Water......................................................88.0

b.u.t.tERMILK

Nitrogenous matter..........................................4.1 Sugar.......................................................3.6 Fat.........................................................0.7 Mineral matter..............................................0.8 Water......................................................88.0

Skim-milk and b.u.t.termilk, when the b.u.t.ter is made from sweet cream and taken fresh, are both excellent foods, although lacking the fat of new milk.