BUTTER-MAKING 245 



destroy the developing organisms already in it, and thus be prepared 

 for the addition of the pure culture. 



3. The addition of the developing "starter" to the pasteurised 

 cream, and the holding of the cream at such a temperature as will 

 readily induce the best development of flavour. 



4. The propagation of the "starter" from day to day. Afresh 

 lot of pasteurised milk should be inoculated daily with some of the pure 

 culture of the previous day, not with the ripening cream containing 

 the culture. In this way the purity of the " starter " is maintained for 

 a considerable length of time. Those " starters " are best which grow 

 rapidly at a comparatively low temperature (60-75 F.), which produce 

 a good flavour, and which increase the keeping qualities of the 

 butter. Now, whilst it is true that the practice of using pure 

 cultures in this way is becoming more general, very few species have 

 been isolated which fulfil all the desirable qualities above mentioned. 

 In America, " starters " are preferred which yield a " high " flavour, 

 whereas in Danish butter a mild aroma is more common. In this country, 

 as yet, very little has been done, and that on an experimental scale 

 rather than a commercial one. In 1891 it appears that only 4 per 

 cent, of the butter exhibited at the Danish butter exhibitions was 

 made from pasteurised cream plus a culture " starter " ; but in 1895, 

 86 per cent, of the butter was so made. Moreover, such butter 

 obtained the prizes awarded for first-class butter with preferable 

 flavour. Different cultures will, of course, yield differently flavoured 

 butter. If we desire, say, a Danish butter, then some species like 

 " Hansen's Danish starter " would be added ; if we desire an American 

 butter, we should use a species like that known as " Conn's Bacillus, 

 No. 41." But whilst these are two common types, they are not the 

 only suitable and effective " starters." On many farms in England 

 there are equally good cultures, which, placed under favourable 

 temperatures in new cream, would immediately commence active 

 ripening. A good lactic acid culture for dairy use (a) should 

 sour cream strongly in a short time, (&) should be able to thrive at 

 low temperatures, and (c) should produce a favourable taste and flavour 

 in the butter (Jensen). 



Professor H. W. Conn, who, with Professor Eussell, has done so 

 much in America for the advancement of dairy bacteriology, reports 

 a year's experience with the bacillus to which reference has been 

 made, and which is termed No. 41.* It was originally obtained 

 from a specimen of milk from Uruguay, South America, which was 

 exhibited at the World's Fair in Chicago, and proved the most 

 successful flavouring and ripening agent among a number of cultures 

 that were tried. The conclusions arrived at after a considerable 

 period of testing and experimentation appear to be on the whole 

 * Report of Storr's Agricultural Expt. Sta., State of Connecticut, 1895. 



