UNSWEETENED CONDENSED MILK DEFECTS 265 



spection, that the steam-distributing pipe is in proper operating 

 condition. If these precautions fail to remedy the trouble, then 

 the entire process is inadequate and either more heat, or longer 

 exposure to the same heat is necessary. 



Spitzer and Epple 1 investigated a case of bitter evaporated 

 milk, in which the troublesome organism appears to. have been 

 of a different type than was the case in the bitter evaporated 

 milk epidemics under observation by Hunziker, as described 

 above. Spitzer and Epple found the bitterness to be due to the 

 presence in the evaporated milk, of an organism that corresponds 

 with Migula's (1900) classification of Bacillus panis as described 

 by Lawrence and Laubach. 2 



This organism is a non-motile bacterium, rod-shape, with 

 rounded ends and measuring about .4 by 2.0 microns. It is spore- 

 bearing, the spores forming readily in 48 to 72 hours and ap- 

 pearing usually near the center of the rod. The organism is 

 capsulated and is very resistant to heat. Spitzer and Epple 

 found it to survive a temperature of 250 degrees F. for 8 minutes, 

 but was destroyed at the same temperature upon 10 minute 

 exposure. The organism does not form gas, it does not swell 

 the cans, nor does it coagulate the casein. The contents of the 

 cans appear perfectly normal to the eye, the only change noticeable 

 is the intensely bitter taste. It is an active proteolytic germ 

 capable of secreting enzymes which are proteolytically active, 

 rapidly breaking down the proteids of milk into large quantities 

 of peptones and lower nitrogenous compounds of complex nature. 

 The authors suggest that the excessive peptonizing function of 

 this organism may be the primary cause of the bitterness. 



The description of the cultural characteristics and thermal 

 death-point of this organism suggests that the presence of this 

 germ in the evaporated milk, and the spoilage of the product, 

 are not due to a faulty process of sterilization, but are the result 

 of conditions in the factory that permit this germ to lodge and 

 to contaminate the milk. Unsanitary condition of pipes, pumps, 

 homogenizer, filling machine, etc., would be the most likely 

 breeding places and sources of contamination. 



1 Spitzer and Epple, Bitterness in Evaporated Milk, Journal of Dairy 

 Science, Vol. III., 1920. 



2 Lawrence and Laubach, Studies on Aerobic, Spore-bearing, Non-path- 

 ogenic Bacteria, Journal of Bacteriology, Vol. I., p. 493. 



