178 Defects of Milk. 



tain periods during the feeding of the incriminated feeds, or while 

 the cows are feeding in certain pastures. According to observa- 

 tions they are observed more frequently in the fall, and during 

 wet, foggy weather than during other periods. 



These defects persist tenaciously in creameries and dairies 

 and can only be eradicated after a thorough determination of their 

 origin. Disinfection of the milk room and utensils with milk of 

 lime and hot soda solution, and extending this disinfection to the 

 stable in association with cleaning of the animal and possibly an- 

 tiseptic infusions of the milk cisterns may yield the desired results. 



Another organism causing "blue milk" is the Bacterium cyan- 

 eofliiorescens (Zangemeister). It is actively motile, bipolar, flag- 

 ellated, grows on gelatin in the form of whitish colonies with in- 

 dented borders and produces a fluorescent coloring matter in the 

 nutritive media. The culture has an odor of trimethylamin and 

 putrid fish. The bacteria produce dark blue spots in milk which 

 change to a sky-blue color after coagulation of the milk. Other 

 blue bacteria are those which occur on hay dust, in water, and in 

 sewage in the vicinity of cheese factories, in ditch-water, and also 

 the bacteria cultivated by Voges, Claessen, and Beijerinck which 

 have been described under the names of B. cceruleum, B. indigan- 

 aceum, B. cyaneofuscum. 



According to the observation of Weigmann and the descrip- 

 tion of Hallier certain hyphomycetes may also possess the faculty 

 of producing a blue coloration; this is accomplished by the ac- 

 tion of the blue coloring matter which they harbor. 



In the zone of the milk supply of Munich ordinary milk de- 

 fects occur very rarely; the author observed them in only one 

 dairy, and was able to trace the trouble to a certain farm. An- 

 other defect of milk occurs much more frequently in the vicinity 

 of Munich, the cause of which, according to the author, has not 

 yet been described. It concerns the production of brownish milk. 



The bacterium of brown milk appears to be closely related in all its characteristics 

 to the producer of blue milk; it is 2.4/x. long, 0.5/u, broad, unipolar, flagellated, actively 

 motile, Gram-positive and remarkably resistant to drying. In gelatin it grows especially 

 well aerobically as a fine, iridescent deposit, which later becomes somewhat thicker, 

 turning to a chestnut brown color. The oxygen zone of the lactose gelatin retains a 

 saturated brown to deep brownish red discoloration, the nutritive media becoming alkaline 

 to litmus. 



A culture of the brown milk organism may be readily produced in milk by rubbing 

 traces of the culture of milk having such a defect upon the bottom of a large Petri-dish, 

 and pouring over it fresh (not sour) milk. In most instances after 15 to 20 hours 

 ocher-colored" to sepia-brown spots develop in the cream layer, which enlarge and 

 coalesce, conveying to the milk a milk and coffee-like appearance. After coagulation 

 the superficial layer of milk again liquefies ; whether this is brought on by the bacteria 

 of brown milk alone or by peptonizing bacteria which multiply especially well when 

 mixed with the bacteria of brown milk, which render the media alkaline, has not yet 

 been established. The skimmed milk is not discolored by the Bacillus fuscogenes. The 

 brownish color gradually diminishes from the surface down and at a depth of 5 mm. 

 it disappears. 



If the milk is allowed to sour the appearance of gray, orange- 

 red, red, yellow, green-fluorescent and violet spots may frequently 



