PASTEURISATION OF MILK AND CREAM. 5 
oT 

exact temperature and time limit at which che tubercle 
bacillus loses its vitality have, however, indicated that an 
exposure of 140 F. for 20 minutes is, in ordinary circum- 
stances, sufficient to destroy the organism of bovine tubercle, 
and this result, if confirmed by further tests on a practical 
scale, should permit of such modification of the pasteurising 
temperature as would overcome the usual objections urged 
against pasteurised products. | 
The experiments of Messrs. Farrington and Russell were 
accordingly designed to d2termine the effect of a temperature 
of 140° F. on the consistency and creaming property of milk. 
The plan of the experiment is described as follows :-— 
“rom a quantity of thoroughly mixed 4 per cent. milk 
that had first been run through the separator, a sample jar 
was filled and placed in cold water. This raw milk, marked 
‘Normal,’ served as astandard for comparison. The balance 
of the same milk was then heated in a Pott’s pasteuriser 
Eomaeetemperatuce of Io. for varying periods of time 
(15-60 minutes) and several samples withdrawn. The remain- 
der of the milk was then raised to the ordinary pasteurising 
temperature, 155 F., for 15-30 minutes, and also sampled 
in a similar way. All samples were then kept in cold 
running water at atemperature approximating to 50 F. Daily 
observations were made as to the thickness of the cream 
line on each jar and as to the keeping quality of the milk. 
One of the advantages to the consumer in the use of bottled 
milk as against the more primitive method of dipping from 
cans is that the quality of the milk can be approximately 
estimated by the thickness of the cream layer. In pasteurised 
products the cream does not rise readily, and naturally the 
purchaser infers that the quality is inferior, whereas it may 
contain a normal amount of fat.” 
The thickness of the cream on the samples of milk heated 
FOMua5  eamd?, 140° F, respectively, compared with that on 
normal milk, as shown by these experiments, is given below. 
Vhe samples heated to 140° F. were taken in triplicate. 
