226 BACTERIA IN MILK AND MILK PRODUCTS 



He considers the injurious properties of such milk is due to ftecal 

 pollution and the action of B. coli (in particular those coliform 

 bacilli which produce a large amount of acid and do not coagulate 

 milk). Newsholme considers such contamination may be responsible 

 for setting up epidemics of diarrhoea occurring in connection with 

 a particular milk supply, as in the analogous case of epidemics of 

 infectious diseases, such as typhoid. But he holds that the ordinary 

 sporadic cases of diarrhoea, which carry off single children in large 

 numbers in urban districts, are due " chiefly to domestic infection 

 of milk or other foods, or to direct swallowing of infective dust."* 

 Probably, we have a double pollution of milk in actual practice, 

 one originating at the farm, one brought about subsequently. The 

 latter may be produced by flies, or from manure heaps (Waldo), or 

 from dust in roads and yards of towns (Eichards), or from the 

 generally filthy manipulation of the milk from the time when it 

 becomes the property of the milk -seller to the moment of con- 

 sumption. It should not be forgotten in this relation that stale 

 milk contains toxic properties altogether apart from, and in addition 

 to, actual bacteria. It is possible that the products of organismal 

 action have a much greater effect in the causation of diarrhoea than 

 is generally supposed, f 



Preventive Measures 



It is not possible in the present state of our knowledge in respect 

 of milk bacteriology to lay down very exact limits as to what is, and 

 what is not, unsatisfactory milk. A numerical standard of contained 

 organisms is not practicable at present. But we think, it may be said, 

 that, in any case, milk should not be considered as marketable if it 

 contains (a) numerous pus cells; (6) pathogenic organisms; or (c) 

 "organisms of indication" of contamination. The presence of vast 

 numbers of bacteria, such as millions per cubic centimetre, also 

 indicates unclean manipulation. 



1. Among the preventive measures which these conditions indi- 

 cate, cleanliness of cows, dairy-hands, ' and milk-cans or other milk 

 vessels, stands first in importance. Refrigeration of the milk, being 

 more easily obtained than cleanliness, should be insisted upon without 

 delay. Similar measures are also needed with regard to all things 

 or persons coming in contact with the milk. Absolute bacterial 

 cleanliness is most difficult to obtain, if not practically impossible. 

 Occasional infection must, therefore, occur. 



2. To guard against the effects of accidental fsecal infection, milk 

 should be consumed fresh, when possible. "When it cannot be con- 



* Report on Health of Brighton, 1902, p. 50. 



t For a fuller discussion of the whole question of the disease-producing power 

 of milk, see Bacteriology of Milk, 1903, pp. 210-391. 



