Whey Milk by Szekely's milk at about 60° C. (140° U.) is treated with carbonic acid at a pressure of 30 atmospheres in a strong, air-tight receptacle which can he closed and is provided with appliances for stirring, where the cheese components are mostly precipitated. Two pnrts of aerated whey are mixed with 1 part of cream, which contains about It) per cent. of fat and 1.5 per cent. of sugar.
Whey Milk by the Monti milk is coagulated at 40° C.(10•1° F.): the whey is freed from ferment at 70° C. (150° F.), and is then mixed with cream or milk.
Peptonized Milk by the which has been heated to 100° C. (212° In') is mixed with sugar, cream, and water as desired, is then treated for a short time at 40° C. (104° F.) with 0.5 per rent. of K.,CO, and a powerful panerea tin, is brought to boil, is combined with somewhat less of phosphoric acid than is necessary to neutralize the potassium. is sterilized for half an hour at 102° C. (215° F.) and is then poured into bottles. The first heating might be omitted with advantage.
Modified Milk by the Backhaus Process.---Aitumed milk is mixed Ivith rennet. trypsin, and 0.5 per cent. and kept in a kettle fur about half an hour at 10° ('. i 10-1° F.): then it is heated to SO° C. (176° F.); the cheese is sifted from the whey, the latter is mixed with cream having 12.4 per cent. of fat, aucl is sterilized in bottles. There are -1 mixtures: (1) 25 cream, 25 water, 50 whey. 2 milk-sugar (1.5 per cent. of albumin, of which 1 per cent. cannot be precipitated by acetic acid): (2) 25 cream. 75 whey. 2 sugar: (3, 25 cream. 25 water, 50 skimmed milk, 2 sugar; (1) 25 creani. 75 skim milk. Baumann pep ionizes the skim milk by papain and adds 1.trea In.
If after any of these operations it is desired to free the milk from germs, it may he sterilized in the bottles 4 from 100° C. to 105° C. (212— 221° F.) by steam or steam-heated water. The Gerher-Wieske appa ratus, with which the bottles are shaken while heating, is advantageous because the sterilization is more certain and the partial fusion of the globules, which otherwise takes place, is prevented. In the latest ap paratus, cooling by water immediately follows sterilization. Sterilized milk should not be browned.
Recently other methods have been proposed for obtaining milk with few germs; e.g., by the addition of formaldehyde in the ratio of from 1: 10.000 to 1:40.000, by which the growth of the lactic o•id germs is decidedly checked, but the proteolytic varieties, and possibly the pathogenic. are not destroyed. This addition is not without interest for infants as pasteurized formalin milk is almost germ free.
In Budde's process, milk, as fresh as possible, is combined with 0.035 per cent. hydrogen hyperoxide. kept for half an hour at 50° C. (122° F.) then for 2 to 3 hours at 52° C. (125.0° F.), cooled, and put in
bottles. A total destruction of time pathogenic germs is not assured. Autodigestion of albuminous matter is probable. The Nectar Company in Paris saturates milk with oxygen. under a pressure of 2 to 3 atmos pheres, in bottles which have a glass ball resting in the neck, and keeps them for 2 hours at 70° C'. (15° F.) The oxygen is perhaps without importance.
Irradiation of ultraviolet light I eiffert t, the conduction of alter nating electrical currents of 110 volts by means of carbon electrodes (Guarini and Santorini), and ozonization (Dorn) have never as yet been tested.
The production of buttermilk will also be a field for the milk labora tories. Yet it has not been determined whether we may rely on the an tagonism of the organisms that produce lactic acid to the butyric acid bacilli and the proteolytic microbes or whether aseptic milk must be used for this purpose also. This would rob the buttermilk of its com mercial advantage. Ordinary buttermilk is valued at 1 cent a quart. Perhaps in the case of buttermilk both superior and ordinary grades will be produced. Since more butter can be obtained from cream that is slightly sour and granular than from sweet, most of the cream has always been allowed to sour. In spontaneous acidification the un welcome germs of decay may grow profusely. For this reason, as early as 1S91, acidifiers, either liquid or made into a powder with flour, were introduced into the market. These are, however, not always fresh cul tures of the Bacterium acid i lactiei: in fact, they more often contain the bacilli of butyric acid. The dairies propagate these for IS to 24 hours at 30° C. (S6° F.) in pasteurized skim milk. or add them directly to the cream, which has already been pasteurized and cooled to 5° C. (41° F.). This now stands for 1S to 24 hours, at from 16°-20° C. (60°— 6S° F.) and is occasionally gently stirred until it reaches an acidity of 24 to 30 degrees, which the specialist can ascertain by tasting. Then the cream is made into butter at 11°-16° C. (52°-60° F.) producing at the same time a buttermilk with about 91 per cent. of water, 0.5 per cent. of fat, and over 3 per cent. of albumin, having the appearance of fatty milk, a purely sour taste, without bitterness, and an acidity of 24 to 30 degrees. The casein (especially that from cream in its native state) is said to he pulpy, not granular. The usual practice of pouring cold or warm water into the churn should of course not be adopted here. Whether buttermilk made from pasteurized unskimmed milk, as re cently attempted, will be equally valuable is still doubtful, as in former attempts the casein produced was far too gritty. On the whole, an accurate chemical and bacteriological study of a satisfactory butter milk has long been needed.