( Originally Published 1939 )
Pediatricians have many cases that require human milk. These may be prematures, difficult feeding cases, or hospitalized infants. In several of the larger communities, agencies have been established to supply this need. The milk is taken from nursing mothers who volunteer and sell this milk at a stipulated price. In New York in 1936 it was bought at 13 cents an ounce (plus carfare), and sold to hospitals at 25 cents an ounce, and to private individuals at 30 cents. Inasmuch as the problems connected with the composition, nutritive value, bacteriological culture value, and epidemiological significance are similar to those which obtain for cows' milk, it is necessary that sanitary precautions be taken in the handling of this milk similar to those which obtain in the regular dairy industry. Rosenau points out that there is need of studying the significance of the bacteriology of mothers' milk in relation to infant welfare.
Table XVII contains a comparison of the composition of human and cows' milk:2
All mothers who have milk to sell must first register at the dispensing agency. Each new mother should have had a negative Wassermann test within the preceding six months, should have an immediate sputum examination, should be nursing a well baby who is under the regular supervision of the physician of the agency, and should pass a careful medical examination as to her freedom from communicable disease and her physical well-being. If her own baby loses weight, her supply of milk is rejected by the agency. The service of a mother is discontinued when her own baby is 12 months of age.
Before coming to the station, the contributing mothers first care-fully wash their entire breasts with soap and water and wear clean dresses of washable material. They should put on caps to cover their hair before entering the milking booths. They wash their hands with hand brush, liquid soap, and running water for 4 to 5 minutes; nails are cleaned with individual orangewood sticks, boiled after using. After drying their hands on paper towels, they each take two clean paper towels with them into the booths. The attending matron washes the mothers' hands and then cleanses their nipples. Each mother strips her own breast by expressing her milk with her forefinger and thumb directly into a sterile glass graduate. The matron transfers the milk to a sterile glass bottle kept in a pail of iced water at 40° F.
Each afternoon the day's supply of milk is pasteurized by placing the bottles of milk in wire racks and immersing them to just be-low the necks in water heated to about 160° F. so that the milk gently agitated attains a temperature of 140°-148° F. during a 30-minute holding period. The milk bottles are then slowly cooled to 40° F., and finally packed in ice for distribution. This pasteurization and treatment should be under the supervision of the milk inspection service of the health department. This is the procedure practiced by the Children's Welfare Federation, New York.
Mothers' milk has been preserved by heating and by freezing. In the first method, the milk is placed in sterile utensils and boiled for 3 minutes. It is then cooled and strained, poured into 8-ounce Mason fruit jars, sealed tightly, placed in a cold water bath, and brought to boil for 20 minutes on each of 3 successive days. After boiling, the bottles are chilled, the caps are tightened, and then the bottles are placed in a refrigerator at 40° F. Homogenization is desirable to preclude the rising of the cream. Such milk will keep satisfactorily in 40° storage for a year.
In the freezing method, the milk is collected and pasteurized in the regular way. Then a metal plate with pocket molds is laid on a block of dry ice. When the plate has been chilled to the temperature of the dry ice (about — 80° C. or -112° F.), the pocket molds are filled with the milk from a sterile glass syringe. Then the mold is covered with a flat plate on which has been placed a block of dry ice. The milk is frozen in about 2 minutes, the covers are re-moved, and the frozen milk wafers are transferred to a sterile container with sterile teaspoons. The container is capped and placed in a holding cabinet at a temperature of about -15° F. Under these conditions, the milk will keep indefinitely.' It can be thawed by immersing the receptacle containing the wafers in cold water for 1/2 hour or by allowing the container to stand in an ordinary icebox until thawed. When delivered to hospitals, nurseries, or physicians, the thawed breast milk is placed in sterile capped bottles and packed in ice. Human milk has also been preserved by drying, but the work of Eddy and Morris 5 has shown that freezing appears to be slightly preferable in that drying seemed to cause some destruction of vitamin A, although freezing also seemed to reduce vitamin B slightly. Philpott and Barrett state that the bacteria count decreases in the frozen milk during storage.
1. M. J. RosExAu, Preventive Medicine and Hygiene, D. Appleton-Century Co., New York, 6th ed., 1935, p. 775.
2. W. CLAYTON, Colloid Aspects of Food Chemistry and Technology, J. & A. Churchill, London, 1932, p. 275.
3. P. W. EMERSON and W. PLATT, J. Pediat., 2, 472 (1933).
4. N. W. PHILPOTT and C. V. BARRETT, Canadian Med. Assoc. J., 36, 505 (1937).
5. W. H. EDDY and S. G. MORRIS, J. Pediat., 4, 208 (1934).