2 BULLETIN 576, U. S. DEPARTMENT OF AGRICULTURE 
PASTEURIZATION OF SKIM MILK IMPORTANT 
It is advisable to pasteurize the fresh skim milk just as it comes 
from the separator, and to begin manufacturing as soon as possible, 
in order to control the fermentation or souring to the best advanage- 
No trouble need be experienced 1n making a high quality of cottage 
cheese, possessing both the characteristic flavor and body, from prop- 
erly pasteurized skim milk of good quality. Pasteurizing the milk at 
a temperature of 145° F. for 30 minutes in no way affects the coagu- 
lability of the milk or the handling of the curd in making cottage 
cheese. A higher temperature, however, should be avoided, as it 
gives a fine curd which is much harder to handle during the process 
of mar:ufacture. Perhaps the greater portion of the cottage cheese 
used is made from raw skim milk, but the benefits to be derived from 
proper pasteurization are so great as to make it highly advisable. 
Pasteurization adds but little to the cost of making and has the 
following important points in its favor. 
1. It insures a food product free from all danger of disease-producing bac- 
teria. 
2. It makes it possible to exercise a more perfect control of souring through 
the use of pure-culture starters, thus insuring the formation of an acid curd 
giving the characteristic, mild, sour-milk flavor so much desired. 
Pasteurization requires little additional work, if suitable equip- 
ment is available. The use of a pasteurizing vat, so elevated as to 
allow the pasteurized milk to run into the making vat by gravity, 
gives most satisfactory results. ! 
EQUIPMENT REQUIRED 
Any equipment needed for making cottage cheese, in addition to 
that already in the creamery or milk plant, depends upon the ap- 
paratus on hand and whether the skim milk is to be pasteurized. 
When a pasteurizer and a channel-bottomed vat are available, very 
little expense is necessary. Assuming that the skim milk is to be 
pasteurized, the following-named apparatus will be needed: Pas- 
teurizer, channel-bottomed cheese vat, curd knives, curd pail, vat 
whey strainer. 
° PASTEURIZER 
The holding system of pasteurization is to be preferred. It re- 
quires a pasteurizing vat which may also be used for cooling the 
skim milk to the ripening temperature, after which the milk is run 
into the making vat. The skim milk for more than one batch of 
cheese may be handled in one pasteurizing vat, provided all of it 
does not have to be taken care of at once. 
In case the flash method of pasteurization is used, it is advisable 
to guard against having the temperature too high. From 165° to 
170° F. is about right. 
CHEESE VAT 
A Cheddar-cheese vat of the ordinary channel-bottomed_ type 
is often used for the purpose of heating the curdled skim milk. 
