Bacteria cause several different kinds of fermenta- tion in milk. The souring of milk is lactic acid fermen- tation. Bacteria produce lactic acid from the lactose (milk sugar), and acid coagulates the casein which separates the curd and leaves a liquid residue — the whey. This whey contains the sugar, salts and al- bumen of milk. There is also a small quantity of a new proteid, produced by decompositions of the casein, called whey-proteid. The curd formed in human milk is more finely divided than in cow's milk, hence it is more digestible. In feeding children and invalids on cow's milk, the lump condition of the curd may be obviated by ad- dition of lime-water or barley-water to the milk. Souring during thimder-storms is due to the warm humidity which is very favorable to the growth of lactic acid bacilh. In but)Tic-acid fermentation, which is caused by about twelve different organisms, the ferment acts as a digester of albumen, which it attacks and gradually dissolves. This ferment produces rancidity in butter. Buttermilk is produced by an alkaline fermentation due to bacteria slow of growth and able to endure a high temperature. Certain bacteria cause slimy milk in which cream will not rise, nor will the milk churn. Milk of this condition is used in Edam cheese. Blue milk is caused by lactic acid and other bacilli MILK 55 (rod-shaped bacteria are called bacilli). It is due to outside contamination and renders the milk alka- line. Blue milk is formed only in the presence of lactic acid. To Prevent Contamination. Avoid sources of im- purity, viz. — imcleanliness of stable, cow, milker, vessels, etc. Avoid conditions favorable to germ growth, viz. — warmth and moisture. Remedies. The remedies are of four classes : — a. Chemical preservatives, as carbonate of soda, nitre, glycerin, salicylic acid, borax, boric or boracic acid, and formaldehyde. Their effect on the power of digestion is ciimulative. Some of them make milk less digestible and nutritious, and may produce dangerous results. b. Filtration. Pass milk through paper or filter presses (not satisfactory) or through sand to remove dirt. Only one-third of the bacteria cells are elimi- nated but this is considered satisfactory from a me- chanical and bacterial standpoint. c. Sterilization. Milk is sterilized at boiling tem- perattire and somewhat decreases the digestibility of milk. It does not kill typhoid bacilU, but a second boiUng destroys them. Tuberculosis bacteria are killed at 160° F.; diphtheria bacteria at 140° F.; pneumonia bacteria at 160° F., and cholera bacteria at 140° F. d. Pasteurization. This is sterilization at 75° Centigrade (below boiling point). The milk is then cooled quickly. This process destroys most of the germs and does not affect digestibility as does steril- ization at the boiling point. Adulteration. Water is sometimes added to milk 56 DOMESTIC SCIENCE after cream has been removed. Coloring matters used are caramel, tm^mene, chalk, saffron. Preservatives used are salt, borax, etc. For thickening after dilu- tion, flour, arrow-root, chalk, sugar and farina are used. Milk should be inspected and tested by chemi- cal means. Legal standards differ in different states. Special Preparations. — Modified Milk. This is separated into parts and recombined, according to prescription. Condensed Milk — water 28%, casein 17.2, fat l4.5, lactose 8.7, cane sugar 27.6, mineral 4.0, total 100. The water in milk is evaporated in vacuum pans at moderate temperature and cane sugar added. Some fat has been lost with the water. Condensed milk may be plain or sweetened. Peptonized milk is milk partly digested. Pancreatized milk is milk in which the change occurs in the pancreas. Dessicated milk; the water is evaporated and the residue is used in the form of powder, with water, for infants' food.

AI-modernized reading of the original text

Bacteria cause several different kinds of fermentation in milk. The souring of milk is lactic acid fermentation. Bacteria produce lactic acid from the lactose (milk sugar), and acid coagulates the casein which separates the curd and leaves a liquid residue — the whey. This whey contains the sugar, salts and albumen of milk. There is also a small quantity of a new proteid, produced by decompositions of the casein, called whey-proteid. The curd formed in human milk is more finely divided than in cow's milk, hence it is more digestible. In feeding children and invalids on cow's milk, the lump condition of the curd may be obviated by addition of lime-water or barley-water to the milk. Souring during thunder-storms is due to the warm humidity which is very favorable to the growth of lactic acid bacilli. In butyric-acid fermentation, which is caused by about twelve different organisms, the ferment acts as a digester of albumen, which it attacks and gradually dissolves. This ferment produces rancidity in butter. Buttermilk is produced by an alkaline fermentation due to bacteria slow of growth and able to endure a high temperature. Certain bacteria cause slimy milk in which cream will not rise, nor will the milk churn. Milk of this condition is used in Edam cheese. Blue milk is caused by lactic acid and other bacilli (rod-shaped bacteria are called bacilli). It is due to outside contamination and renders the milk alkaline. Blue milk is formed only in the presence of lactic acid. To Prevent Contamination. Avoid sources of impurity, viz. — uncleaniness of stable, cow, milker, vessels, etc. Avoid conditions favorable to germ growth, viz. — warmth and moisture. Remedies. The remedies are of four classes : — a. Chemical preservatives, as carbonate of soda, nitre, glycerin, salicylic acid, borax, boric or boracic acid, and formaldehyde. Their effect on the power of digestion is cumulative. Some of them make milk less digestible and nutritious, and may produce dangerous results. b. Filtration. Pass milk through paper or filter presses (not satisfactory) or through sand to remove dirt. Only one-third of the bacteria cells are eliminated but this is considered satisfactory from a mechanical and bacterial standpoint. c. Sterilization. Milk is sterilized at boiling temperattire and somewhat decreases the digestibility of milk. It does not kill typhoid bacilli, but a second boiling destroys them. Tuberculosis bacteria are killed at 160° F.; diphtheria bacteria at 140° F.; pneumonia bacteria at 160° F., and cholera bacteria at 140° F. d. Pasteurization. This is sterilization at 75° Centigrade (below boiling point). The milk is then cooled quickly. This process destroys most of the germs and does not affect digestibility as does sterilization at the boiling point. Adulteration. Water is sometimes added to milk after cream has been removed. Coloring matters used are caramel, turmene, chalk, saffron. Preservatives used are salt, borax, etc. For thickening after dilution, flour, arrow-root, chalk, sugar and farina are used. Milk should be inspected and tested by chemical means. Legal standards differ in different states. Special Preparations. — Modified Milk. This is separated into parts and recombined, according to prescription. Condensed Milk — water 28%, casein 17.2, fat l4.5, lactose 8.7, cane sugar 27.6, mineral 4.0, total 100. The water in milk is evaporated in vacuum pans at moderate temperature and cane sugar added. Some fat has been lost with the water. Condensed milk may be plain or sweetened. Peptonized milk is milk partly digested. Pancreatized milk is milk in which the change occurs in the pancreas. Dessicated milk; the water is evaporated and the residue is used in the form of powder, with water, for infants' food.

Domestic science (Clark, Cornell home economics)