DAIRY FARMING DAIRYING. 77 



milk may be either stimulated or retarded by association with other micro- 

 organisms. Stimulation in both rapidity and duration occurs if in the medium 

 are present some acid-destroying or acid-retaining compounds, as insoluble car- 

 bonates, casein, etc. A factor which may stimulate the growth of D. lactis acidi 

 when growing in association with liquefying organisms is an increased supply 

 of food made available by the proteolytic changes, as for example, the addition 

 of peptone. 



The growth of most of the organisms commonly found in milk may be either 

 stimulated or retarded by association with B. lactis acidi. " The changes caused 

 in milk by many micro-organisms In pure culture are greatly retarded or pre- 

 vented if at the beginning an equal number of B. lactis acidi is introduced ; the 

 organism alone producing its characteristic changes while in the association the 

 changes produced are those characteristic of the lactic alone. If, however, the 

 organism is given a lead before the lactic is introduced, it is able, usually, to 

 make its changes detectable. . . . 



" Changes occurring in milk as a result of the associative growth of a lactic 

 with another organism are influenced by the change in reaction, the accumula- 

 tion of metabolic products of both the organism and the lactic, the temperature 

 of growth, the accessible supply of oxygen, etc. However, the hindrance or 

 encouragement in the production of enzyms offered by the lactic through Its 

 metabolic products to other organisms growing in association is a factor that 

 can not be overlooked." 



Biorized milk, Klunkeb (MoJk. Ztg. iHUdeshcim], 28 (19U), Nos. 33, pp. 

 625, 626; 3^, pp. 639, 640). — In investigations made of the Lobeck milk sterili- 

 izatiou process at the Institute of Hygiene, University of Jena, it was demon- 

 strated that the apparatus is convenient to handle, the loss of milk is small, 

 and the biorized milk is equal in appearance and flavor to the best raw milk. 

 It is somewhat less easily skimmed than raw milk, although the difference is 

 of little consequence. The original enzyms of the milk are not influenced by the 

 process nor are the proteins altered. Coagulation is less rapid but is not 

 weakened. The germ content is so lowered that the keeping quality of the milk 

 is greatly increased, and the disease-producing germs are destroyed. 



Milk sterilization by electricity, J. B. C. Kershaw {Engin. Mag., 1ft (1914), 

 No. 6, pp. 916-919, fig. 1). — Experiments on the effects of a rapidly alternating 

 current at high potential in milk sterilization showed that disease-producing and 

 milk-souring bacteria were practically destroyed in the raw product, there being 

 a reduction in the total number of bacteria of 99.93 per cent. The chemical 

 constitution of the electrically treated milk was unimpaired and the taste was 

 in no way altered. The milk was not only rendered nonpathogenic as regax'ds 

 ordinary bacteria, but in two cases in which the control supply was tuberculous 

 the electrically treated milk was free from tubercle bacilli and regarded as a 

 satisfactory food for infants. 



Composition of Roquefort-cheese fat, J. N. Currie (U. S. Dept. Agr., Jour. 

 Agr. Research, 2 {1914), No. 6, pp. 429-434)- — Comparing the composition of the 

 fats of Roquefort cheese and of cow's milk it was found that the Reichert- 

 Meissl number of the cheese fat ranged between 25.G4 and 29.02, while that of 

 cow's milk fat was 27.27; the Polenske number between 5.5,5 and 6.25, that of 

 cow's milk fat 2; soluble acids of 5 gm. of cheese fat expressed in cubic centi- 

 meters of tenth-normal acid between 38.8 and 41, cow's milk fat 26 ; and insol- 

 uble acids of cheese fat between 18.01 and 19.2, and cow's milk fat 11.17. The 

 percentage of acids in the fats of Roquefort cheese as determined and of cow's 

 milk as reported by Browne (E. S. R., 11, p. 615) were respectively as follows: 

 Butyric 3.48 and 5.45, caproic 4.73 and 2.09, caprylic 0.58 and 0.49, capric 3.8 



