EXPERIMENT STATION BULLETINS. 



485 



Table III. — Bacterial Content of the Mix Before and After Homogenizing 



have is'Iiown that the 'homogeuizer may il>e 'a isiouirce lof ooiitaniination espe- 

 ciallj' for the first miaterial passinig through. They ran the ice cream 

 mix through the ihomogenizer bio'tih ■w(ith and without pre.ssure ami found 

 that without pressure there was an increase in all eases. They concluded 

 thait the increase waig due to contamination from the (hiomiogenizer because 

 in all cases the figures lobtained were 'on the first miateriail ipassing through 

 the homiogenizer. As the procesis was ^continued the ipresumption was 

 that the tcontajminiation would .become less due to the washing effect. 



The second icauise of an increaise in the baicterial count may be the 

 breaking up of clumpis of baicteria ais the mix ipaisises tlirough the homio- 

 genizer under pressure. The imcreaise in this case woiuld be an apparent 

 rather than a real increase and should be taken into consideration in 

 formulating a l>a:cterial staiixlaird for ice cream. 



The increases noted in Table III are presumaibly due to the second 

 cause becaiuse the samples were obtained in a imiajority of the caises in the 

 middle of the forenoon or shortly after noon to allow suflicient time to 



