14 BULLETIN 342, U. S. DEPARTMENT OF AGRICULTURE. 
seem to prove this point, it has never been thoroughly established. It 
has been found that the rate of bacterial increase is approximately 
the same when the comparison is made between raw milk and pas- § 
teurized milk having about the same bacterial content. 
Tt is often stated that pasteurization, even if it does destroy bac- 
teria, does not destroy poisonous products of their growth. This § 
can hardly be considered a real objection, for if they are present in | 
raw milk they must be consumed with it, and if pasteurization does § 
not destroy them the pasteurized milk would be no worse than the 9 
raw milk. 
The question as to whether pasteurization destroys beneficial enzyms 
is still an open one. in the light of our present knowledge of the — 
enzyms in milk and the part they play in the digestive process it is | 
quite impossible to settle the question of their importance. It is | | 
evident, however, that the low temperatures now in use in pasteuriza- 
tion have little effect on the commonly recognized enzyms. 
The opponents of pasteurization have raised an objection on the @ 
ground of its direct influence on the milk producer. It has been 
asserted that pasteurization would cause lax methods of production 
on the farm, for the reason that farmers would know that the milk | 
was to be pasteurized and, therefore, they could be careless in its 
production. There seems to be some basis for this objection, but in — 
any city where there is any inspection of the raw-milk supply the © 
same inspection can and should be continued even though the milk | 
is to be pasteurized. 
From a chemical standpoint serious objections have been raised — 
against pasteurized milk, because the heating produces changes which | 
render the milk less digestible, particularly in the case cf infants. | 
As has already been stated, however, Rupp has found that milk | 
pasteurized at 145° F. for 30 minutes does not undergo any appre- | 
ciable chemical change. He found that soluble phosphates do not | 
become insoluble, that the albumin does not coagulate, and that when 
higher temperatures are used chemical changes do occur. He also 
developed the fact that 5 per cent of the albumin is rendered in- 
soluble in milk heated for 30 minutes at 150° F., while at 160° F. 
30.78 per cent of the albumin is coagulated. According to Hess (14), 
however, milk pasteurized 30 minutes at 145° F. may cause, in infants, 
a mild form of scurvy, which yields readily to such a simple remedy 
as orange juice. | 
Further evidences that low-temperature pasteurization does not — 
injure the digestibility and nutritive value of the milk is shown by | 
the results of feeding experiments on babies. According to Weld (13) — 
a number of babies that were fed raw milk and pasteurized milk — 
showed only a slight difference in the average net daily gain im 
weight during the feeding period. The shght daieeene was in favor — 
of pasteurized milk. : 
MoS: id, 
