STERILISATION 541 



considerably above the boiling point and maintaining such a 

 temperature for some minutes, or by intermittent or discontinuous 

 heating. Both methods have disadvantages. The former requires 

 special apparatus (autoclave), and has an unfavourable effect upon 

 the milk, the latter is tedious and cumbersome. Practically 

 speaking the ordinary sterilisation which is used in general is 

 boiling (at 212" F.), and in some quarters the demand for such milk 

 is increasing. Undoubtedly, the only safe, simple, practicable 

 method for domestic protection against infected milk is to boil it, 

 and we have no hesitation at all in recommending the private 

 consumer, either to treat his milk as described on pp. 10 or 537 

 as domestic pasteurisation, or to boil it. If all dairy work were 

 properly done we hold such boiling would not be necessary, but 

 under the present circumstances this form of simple " sterilisation " 

 is advisable. 



The application of sterilisation to milk is now very widely 

 adopted. We have already noted its adoption by Liverpool and 

 other Corporations for special purposes, by many of the great dairy 

 companies, and by domestic custom. Recently we have had the 

 opportunit>- of studying an excellent system in vogue in Essex,^ 

 and which we mention in particular because it seems to us to 

 emphasise principles which might be practised all over England. 

 Briefly it may be said that Mr Carson's system lays emphasis on 

 five chief points : — 



1. The cows used are carefully selected for milking purposes, 

 are regularly inspected, and have been tested with the tuber- 

 culin test The farm is well kept and maintained under strict 

 sanitary control, the health and cleanliness of the cows being the 

 principal thing aimed at 



2. The cows are milked in the byre adjoining the sterilising 

 plant The udders are cleansed before milking, and it is required 

 that milkers also should be clean in person and management of 

 milking. 



3. Immediately after milking, the milk is removed into an 

 adjoining room, strained through a metal screen, and at once 

 separated by an ordinary Laval separator. This separation is 

 adopted for purposes of purification only. The milk and cream 

 are again mixed, and poured by means of a mechanical automatic 

 bottle-filler into bottles. 



4. The milk in bottles is then, within a few minutes of leaving 

 the udder, placed in the steriliser and maintained at 2I2°F. for 



* J. Carson, Crystalbrook Farm, Theydon Bois, Essex- 



