n6 



MILK AND ITS HYGIENIC RELATIONS 



Rullmann and Trommsdorff agreed with Koning, and showed 

 that the inhibitory effect upon ordinary bacterial flora persisted 

 almost throughout the first day even at room temperature. The 

 inhibitory effect was increased in mastitis. 



The majority of observers who have compared the rate of growth 

 of bacteria in raw and boiled milk believe that the inhibitory effect 

 is destroyed by boiling, and that bacteria grow more readily in 

 milk which has been previously boiled than they do in raw milk. 1 



Myer Coplans showed that the inhibition was exhibited for 

 six hours after milking, at 20 C, partial inhibition persisting for 

 some hours longer. If the milk was kept at blood heat, the 

 inhibition only lasted for one hour, partial inhibition lasting for 

 from two to six hours after milking. At o C. the inhibition persisted 

 for twenty-four hours. 



Rosenau and McCoy (1908) showed (see table below) that the 

 apparent bactericidal effect, as shown by a decrease in the number 

 of colonies obtained on plating out, which occurred in fresh milk 

 was probably due to agglutination of the bacteria, since it could 

 be shown to be entirely absent if the agglutinated masses of 

 bacteria were broken up before the milk was plated out. 



a. = Innumerable. 



b. = About. 



The decrease occurred only in the first six to eight hours after 

 milking, and was not found in boiled milk or in milk heated to 

 80 C. It was not effected by freezing, but was hindered by dilution. 

 The action was specific, since it was not the same for different 

 species of bacteria, nor was it the same in different milks, or 

 even in different samples from the same animal. They also showed 



1 Cp. St. John and Pennington, Moro (3), Myer Coplans. 



