1534 INDUSTRIKS DKPENDI^■G OX ANIMAL I'UODICTS 



II20- Pasteurization of Milk in the Bottle. — in Pun- Producu \oi. xii, No. «, 



PP- 3<^5 392. New- York, August, imi6. 



There are at present three methods by which milk is pasteurized : 

 The " flash " or continuous method ; the " holder " or intermittent method, 

 and the method of pasteurizing in bottles which is the latest device for the 

 pasteurization of milk. 



In the " flash" process milk is heated at 160° to 1650 F. for 30 to 60 

 seconds. This process has the disadvantage that the milk is often heated 

 too high or is scorched, causing the milk to have a peculiar and unpalatable 

 taste. In the "holder" process milk is heated to and kept at 140° F.to 

 14 50 F. for 30 minutes. The pasteurized milk should then be cooled and 

 kept at a temperature below 500 F. The " holder " process, in which com- 

 partments or tanks are employed, does not give a uniformly pasteurized 

 product since the large volume of milk makes it impossible to heat it uni- 

 formly, one coiner or section of the tank being always hotter or colder 

 as the case may be. The tank being necessarily divided into compartments 

 or sections, pockets are created m^^king a positive circulation of milk and 

 therefore a uniformity of temperature in the entire vat or compartments 

 impossible. At any rate in both of these methods — the " flash " and the 

 " holder" process — a recontamination, while filling the milk into bottles 

 cannot be avoided. The third method avoids the risk of recontamination, 

 as the milk is first bottled and then pasteurized. 



Pasteurization of milk is frequently done very inefficiently, usually 

 owing to ignorance or carelessness. When the heat applied is insufficient 

 either in amount or time of application, disease germs are not all destroyed 

 and as a consequence epidemics of streptococci, sore throat, typhoid fe- 

 ver, etc., have started. In order to obtain a uniform product it is essen- 

 tial that not only the pasteurization process must be given the proper at- 

 tention but that proper and efficient devices must be applied in the soaking 

 and rinsing of the bottles. It is useless to apply the most complete pasteur- 

 izing outfit if the bottles into which the milk is to be filled are not cleaned 

 properly, and, on the other hand, it is insufficient to use a clean bottle if 

 the pasteurization process is incomplete. The Barry- Wehmiller System 

 of soaking, washing and rinsing of the bottles, clarifying of the milk, filling 

 and pasteurizing of the filled bottles is said to be the " last word" in the 

 production of a safe milk. A short description of this model plant may 

 serve to give an idea of the arrangement and machinery used. 



As soon as the full cans are received from the wagons they are immedia- 

 tely poured through a screened receiving pan from which the milk floAvs into 

 two 2 000 gallon Pfaudler Glass-Lined Receiving Tanks. 



The tanks are lined with glass enamel on the interior and the inner shell 

 provided with an outer jacket. Within this jacket circulates brine, which 

 keeps the milk cold. The jacket is insulated externally with cork blocks. 

 At the bottom of the tanks are perforated air pipes through which washed 

 and filtered air is supplied under pressure from the aerator and compressor. 

 The action, of this forced air keeps the milk in complete and constant 

 agitation. 



