MILK AFFECTED BY DAIRY PRACTICES. 67 
relation which bacteria play to public health and our knowl- 
edge of the fact that milk is an ideal medium for the growth of 
nearly all species of bacteria, the value of careful bacteriolog- 
ical study of milk has becomeapparent. Physicians agree that 
certain diseases are easily communicated by bacteria being car- 
ried in milk, also that many infants and young children die 
each year as a result of impure milk; impure not from the use 
of adulterants or preservatives but as a natural result of the 
conditions under which it is produced and handled. 
Milk is an extremely good food for a large number of species 
of bacteria and nearly all of the changes which render milk 
undesirable and unwholesome are caused by the presence and 
growth of certain species of this group of micro-organisms. 
Under ordinary methods of producing and handling, large 
numbers of bacteria get into milk. It is highly desirable that 
dairymen should know how to prevent the entrance of these 
organisms into the milk and to so handle it that the growth of 
those which do get in will be reduced to the minimum. It is 
possible to produce a grade of milk which shall contain but 
very few bacteria. This is demonstrated by some of the so- 
called “‘sanitary’’ or ‘‘certified’’ milks which are now on the 
market but these are produced at an increased cost and are sold 
_at a price considerably above that of the regular market milk. 
The average consumer is unwilling to pay the increased price 
charged for this grade of milk yet insists on being supplied 
with a good wholesome article. At the present price which 
the average producer gets for his milk he cannot afford to 
greatly increase his cost of production. In order to meet the 
public demand for a better grade of milk he must therefore 
make use of inexpensive means for preventing the entrance, 
and controlling the growth, of bacteria in his milk. The thing 
of first importance is to prevent bacteria from getting into the 
milk. This must be borne,in mind at every step in the pro- 
duction and subsequent handling but primarily while the milk 
is being drawn from the cow and until it is taken from the 
barn, for it isin the stable that milk usually gets its greatest 
bacterial contamination. In order to ascertain the actual effect 
of some of the common dairy practices upon the germ content 
of the milk the experiments given in this bulletin have been 
made. 
