Report to the Local Government Board upon the effects of certain condensing and drying processes used in the preservation of milk upon its bacterial contents / by Dr. S. Delépine.

  • Auguste Sheridan Delépine
Date:
1914
Catalogue details

Licence: Public Domain Mark

Credit: Report to the Local Government Board upon the effects of certain condensing and drying processes used in the preservation of milk upon its bacterial contents / by Dr. S. Delépine. Source: Wellcome Collection.

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    4. the separator. The separated milk may be dried separately, - in which case the cream is removed. When dried whole milk is wanted the separated milk and cream are brought together again in a common channel which carries the milk to 5. a*pasteurising apparatus where the temperature of the fluid is raised from 70° C. to 75° C. When separated milk is treated the temperature is raised slightly above 75° C. 6. The pasteurised milk is collected in large tin-lined tanks the capacity of which is about 800 gallons. 7. The fluid is then carried by pipes to a large vacuum pan, where it is heated by steam to a temperature of about 58° C. and is reduced to a little less than one-half of its original bulk. When the milk has reached a suitable consistency its temperature is rapidly raised to 95° C., and as soon as this point is reached the temperature is brought down again to 58° C. According to the amount of milk in the vacuum pan the con- densing process occupies from 2 hours to 2} hours. 8. The condensed milk is drawn into metal cylinders from which it is immediately pumped into 9. a small tank, from which the fluid passes into 10. a powerful pump, which forces,it under a pressure of 2,000 to 3,000 lbs. through the t 11. spraying apparatus by which a cone of finely sprayed milk is produced. ‘his takes place in the middle of an opening to which a current of dry air heated to 115° C. is brought by 12. a large pipe. Both the hot air‘and the spray are projected into 13. a tin-lined chamber, the interna] temperature of which 1s 76° to 81° C. The droplets of milk dry as they fall to the floor upon which they rapidly form a layer of granules of dry milk. The current of hot air passes out of this first room into a second room where the particles which have not fallen in the first room are collected. 3 7 iy | When the desired amount of milk has been dried the drying room 1s emptied through an opening in the floor, the milk powder is collected in Be 14. metal cylinders. : 15. It is afterwards sifted through a fine gauze screen. 16. For wholesale purposes the finished product is packed in large bags of thin impervious paper supported by a wooden case. Hor retail purposes the milk powder is packed in paraffined card- board cups of various sizes. About 6,000 gallons of milk could be treated daily at Factory Z. Collection of samples. At the time of our visit whole milk was being treated, and we timed the taking of the samples so as to secure as far as possible correspondence between the samples of untreated and of treated milk. (The samples of dried milk just finished were taken three hours after the samples of fresh milk had been collected.)
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