Ladysmith news-budget. [volume] (Ladysmith, Rusk County, Wis.) 1907-1927, 1907-12-12
iNvENTS NEW MILK TEST.
State University Professor Finds New
Method of Great Value.

Method of Great value.
A simple method of determining the
amount of casein in milk, which bears
the same relation to the cheese indus
trv of the state that the determine
ton of fat content by the Babcock
test does to buttermaking has been de-
vised and perfected by Prof E. B.
Hart of the department Of agricultu-
raj chemistry of the University of
Wisconsin. In bulletin now in press
entitled "a Simple Test for Casein in
Milk and It's Relation to the Dairy
Industry" Prof. Hart sets forth in de-
tial the results of his experiments
and gives practical directions for the
application of the new test. The meth
cd is so simple that it may be used in
any cheese factory with accuracy by
any one exercising reasonable care.
Hitherto it has been possible to deter
mine the casein content of milk only
by a long, tedious chemical process
not adapted to general use.
AS cheese is made up almost wholly
of fat, casein and water, the fat and
casein, under uniform conditions of
cheesemaking, determine the yield of
cheese. 1t has been clearly hown that
in cheesemaking the amount Of caseln
and fat in the milk should be known to
both the man who owns the COW and
the man who buys the milk. The prac-
teal man, as we'll as the investigator,
recognizes the fact that milks vary in
the relative proportion OF casein and
fat. AS there has been no simple
casein test, cheesemalkers have been
compelled to rely upon the fat test to
determine the value of milk for their
purposes. AS milks have been found
to vary in casein from 46 to 73 pounds
for every 100 pounds of fat, it is evil
dent that the fat test is insufficient in
determining the casein content. Thus
the new casein test to supplement the
fat test is of the greatest Importance
to cheesemaking. Such simple test
it is that Prof. Hart has devised.
In order to make the test definite
quantity of milk is put into a tube
containing a solution of chlorofOrm
and acetic acid and is thoroughly mix
ed with these chemicals by shaking.
The purpose of shaking is to bring the
chloroform into contact with the fat
globules of the mill and thereby to
dissolve them. The tube is then
placed in a centrifuge similar to that
used in the Babcock test and is re-
vOlved at a speed of 1000 revolutions
per minute for eight minutes. The
centrifugal force distributes the in
gradients in the tube so that the chic
reform with the fat in solution is in
the bottom and the clear water solu-
ton of the milk solids on top. The
casein forms a sharply defined white
mass between the chloroform and the
water and may readily be measured
by marks on the tube.
The results secured by three differ
ant chemists working separately on
different milks with the old elaborate
chemical method and the simple Hart
Test indicate that when the new meth
I'd is properly conducted it is suffi-
GENTLY accurate for all practical pur-
poses. Tests of the milk of Jersey,
Guernsey Holstein, brown Swiss and
Ayrshire COWS by the old and the new
methods give practically the same re-
suits. To be effective the test should
be made on sweet, unpreserved milk,
as the use of formaldehyde, corrosive
3ublimate, chloroform and toluol seri-
ously affect the results.
The payment for milk for butter pro-
1uction is now generally on the basis
Of the amount of fat, as determined
by the Babcock test. By processes of
selection of dairy COWS the average fat
content in milk has been raised at
east half per cent since the intro
luctiOn of the Babcock test, and the
5kimming and watering of milk has
been prevented. By means of the Hart
lest the value of milk for cheesemak-
ing can be determined and it does not
seem at all impossible that with this
simple casein test a cheese COW can
be developed; that is, one in whose
milk the relation of casein to fat is es-
pecially high.-W.