646 
A uniform heating of 140° F. maintained for twenty minutes ; 150° F. main- 
tained for fifteen minutes ; 155° F. maintained for five minutes ; 160° F. main- 
tained for one and one-half minutes; 165° F. maintained for one minute. 
The time shall be calculated from the period that the entire quantity reaches 
the required temperature. 
Rule 7. Cooling temperatures. — The pasteurized product shall be cooled at 
once to a temperature of 45° F. or less. This cooling shall be so conducted 
that the pasteurized product is not exposed to the air or other contamination. 
This cooling apparatus shall be so constructed that it can be readily cleaned 
and sterilized. 
Xew York. — In the amendments of the sanitary code of the depart- 
ment of health of the city of Xew York additional regulations for 
the sale and care of milk were adopted April 22, 1908. Among the 
additions the following rules apply to pasteurization : 
PASTEURIZED. 
1. Pasteurization of milk must be carried out under a permit therefor issued 
by the board of health, in addition to the usual permit for milk required by 
section 56 of the sanitary code. 
2. The milk after pasteurization must be at once cooled and placed in ster- 
ilized containers and the containers sealed. 
3. All pasteurized milk must be delivered to the consumer in sealed containers 
which are plainly labeled “ Pasteurized.” The labels must also bear the date 
and hour when the pasteurization of the milk was completed, the degree of 
the heat employed, the length of time exposed to the heat, and the number of 
the pasteurization permit issued by the board of health. 
4. Pasteurized milk must be delivered to the consumer within twenty-four 
hours of the pasteurization. 
5. No milk shall be pasteurized a second time. 
CHANGES IN THE MILK PRODUCED BY HEATING. 
The changes produced in milk by heating depend upon the degree 
of heat and the length of exposure. The exposure of milk to a tem- 
perature of 60° C. for a short time does not appreciably affect its 
chemical and physical properties. The boiling of milk, however, 
produces pronounced changes. These changes consists mainly of the 
following : 
Decomposition of the proteins, and other complex nitrogenous 
derivatives; diminution of the organic phosj^horus; increase of inor- 
ganic phosphorus ; precipitation of the calcium and magnesium salts 
and the greater part of the phosphates ; expulsion of the greater part 
of the carbon dioxide; caramelization or burning of a certain portion 
of the milk sugar (lactose), causing the brownish color; partial dis- 
arrangement of the normal emulsion and coalescence of some of the 
fat globules; coagulation of the serum albumin, which begins at 75° C. 
The casein is rendered less easy of coagulation by rennin and is 
more slowly and imperfectly acted upon by pepsin and pancreatin. 
Boiling gives the milk a “ cooked 55 taste. The cream does not rise 
well, if at all. 
