110 THE CREAMERY PATRON'S HANDBOOK. 



noticeable on account of any marked odor but the chemical characteristics 

 of the liquid are sometimes changed. The milk of swill-fed cows, according 

 to Koberand Busey, ofteri has a peculiar taste and odor and is said to produce 

 a hyperacidity of the urine and consequent eczema. Brewer's grains and 

 distillery slops when fed in large quantities frequently induce an abnormal 

 chemical reaction. 



DISCRIMINATION BETWEEN DIRECTLY ABSORBED AND BIOGENIC TAINTS. 



The cause of a tainted condition of milk is not always an easy matter 

 to determine. Much confusion exists in the minds of many in regard to 

 these various phenomena, and the many inquiries received show the im- 

 portance of the subject. In case trouble of any sort arises in connec- 

 tion with the milk supply, it is highly important that intelligent steps should 

 be taken to locate the exact cause of the difficulty. The manner of dealing 

 with a taint due to bacterial infection is so radically different from the 

 treatment of a taint absorbed directly by the milk that the distinction be- 

 tween these two different types of milk faults or defects should be made 

 evident. 



The conditions under which the taint appears in the milk throw much 

 light on its probable cause. If it is pronounced immediately after milking 

 there is but little probability of its being due to any other cause than di- 

 rect absorption. A bacterial taint can only be formed in the milk when 

 opportunity is had for infection and subsequent development of the bac- 

 teria. This requires several hours, so that a taint produced by 

 decomposition changes that are caused by the action of micro- 

 organisms, does not appear until the milk is usually from twelve to twenty- 

 four hours old or even older. The length of time necessary to produce this 

 change is determined mainly by the temperature at which the milk is kept. 

 The appearance of that taint some hours subsequent to milking does not 

 necessarily indicate a bacterial cause. It is entirely possible that the milk 

 may not have been subjected to conditions that favored direct absorption 

 for some hours, and also where the odors were not very pronounced, it 

 might take several hours before they would be absorbed with sufficient in- 

 tensity to be readily detected. Odors due to bacterial development usually 

 become more pronounced with the increasing age of the milk. 



Another simple rule that will aid in the detection of bacterial de- 

 fects is to inoculate or add to a quantity of milk that has just previously 

 been boiled, a small portion of the suspected milk. If in the course of twelve 

 to twenty-four hours, a similar trouble is noted in the inoculated milk, 

 it indicates that the defect is a progressive one and that it is due to the 

 action of living ferments. Taints directly absorbed by milk are incapable 

 of generating themselves in this way. Only living matter possesses this 

 characteristic. Boiled milk is preferable to raw milk, because if ordinary 

 milk is used, the lactic acid forms that are invariably present may repress 



