his method of
manufacture to some extent to meet these new conditions.

~Use of starters.~ A starter may be employed to hasten the ripening of
milk that is extremely sweet, so as to curtail the time necessary to get
the cheese to press; or it may be used to overcome the effect of
abnormal conditions.

The starter that is employed is generally one of domestic origin, and is
usually taken from skim milk that has been allowed to ferment and sour
under carefully controlled conditions. Of course much depends upon the
quality of the starter, and in a natural starter there is always the
possibility that it may not be perfectly pure.

Within recent years the attempt has been made to control the effect of
the starter more thoroughly by using pure cultures of some desirable
lactic-acid form.[178] This has rendered the making of cheese not only
more uniform, but has aided in repressing abnormal fermentations
particularly those that are characterized by the production of gas.

Recently, pure cultures of Adametz's _B. nobilis_, a digesting organism
that is claimed to be the cause of the breaking down of the casein and
also of the peculiar aroma of Emmenthaler cheese, has been placed on the
market under the name _Tyrogen_. It is claimed that the use of this
starter, which is added directly to the milk and also rubbed on the
surface of the cheese, results in the improvement of the curds, assists
in the development of the proper holes, imparts a favorable aroma and
hastens ripening.[179]

Campbell[180] states that the discoloration of cheese in England, which
is due to the formation of white spots that are produced by the
bleaching of the coloring matter in the cheese, may be overcome by the
use of lactic-acid starters.

The use of stringy or slimy whey has been advocated in Holland for some
years as a means of overcoming the tendency toward gas formation in Edam
cheese which is made from practically sweet milk. This fermentation, the
essential feature of which is produced by a culture of _Streptococcus
Hollandicus_,[181] develops acid in a marked degree, thereby inhibiting
the production of gas.

The use of masses of moldy bread in directing the fermentation of
Roquefort cheese is another illustration of the empirical development of
starters, although in this instance it is added after the curds have
been prepared for the press.

~Pasteurizing milk for cheese-making.~ If it were possible to use properly
pasteurized milk in