138 Dairy Bacteriology. 



slightly larger a point of considerable economic impor- 

 tance where large quantities of butter are made. 



Development Of acid. The result of this enormous bac- 

 terial multiplication is that acid is produced in cream, lac- 

 tic being the principal acid so formed. 



Other organic acids are undoubtedly formed as well as 

 certain aromatic products. While the production of acid 

 as a result of fermentative activity is usually accompanied 

 with a development of flavor, the flavor is not directly pro- 

 duced by the formation of acid. If cream is treated in 

 proper proportions with a commercial acid, as hydrochloric, 1 

 it assumes the same churning properties as found in nor- 

 mally ripened cream, but is devoid of the desire J aromatic 

 qualities. Lactic acid 8 has also been used in a similar way 

 but with no better results. 



The amount of acidity that should be developed under 

 natural conditions so as to secure the optimum quality a 

 to flavor and aroma is the most important question in 

 cream ripening. Concerning this there have been two some- 

 what divergent views as to what is best in practice, some 

 holding that better results were obtained with cream rip- 

 ened to a high degree of acidity than where a less amount 

 was developed. 3 The present tendency seems to be to de- 

 velop somewhat more than formerly, as it is thought that 

 this secures more of the "high, quick" flavor wanted in 

 the market. On the average, cream is ripened to about 

 0.5 to 0.65 per cent acidity, a higher percentage than this 

 giving a strong-flavored butter. In the determination of 

 acidity, the most convenient method is to employ the Far- 



'Tiemann, Milch Zeit., 23:701. 



Milch Zeit, 1889, p. 7; 1894, p. 634: 1895, p. 383. 



Dean, Out. Agr. Coll., 1897, p. 60. 



