Pasteurization of Milk 



13 



from the heater throughout the run, 

 and the time of the finish of the dis- 

 charge of milk from the heater. The 

 chart showing the holding time and 

 temperature record of the milk in a 

 continuous flow apparatus, must show 

 the time at which the first milk is dis- 

 charged from the holders, its tempera- 

 ture, the temperature of the milk main- 

 tained through the run, and the time 

 of the finish of the run. The sensitive 

 bulb of the recording instrument must 

 be placed in the continuous flow dis- 

 charge pipe of the holding tanks and 

 not in the pipe through which the milk 

 flows when the tanks are being emp- 

 tied. 



An apparatus having a series of 

 tanks that are emptied at the end of 

 the run, the interval between the fin- 

 ish of the run and the starting of emp- 

 tying the first tank, must be clearly 

 indicated on the chart recording the" 

 temperature of the cold milk ; likewise, 

 the interval between emptying the 

 other tanks of the series will also be 

 indicated on the cold milk chart ; this 

 is caused by interruptions to the flow 

 of the milk in emptying the holders. 



It is of the utmost importance to 

 check the temperature of the first milk 

 discharged from the holders, if this 

 milk does not show 145 degrees or 

 over when the milk supplied from the 

 heater was 145 degrees in a properly 

 constructed apparatus, it indicates 

 that the holders were not properly pre- 

 heated before beginning the operation. 

 This underheated milk may defeat effi- 

 cient treatment, as all of the milk dis-' 

 charged below 145 degrees may carry 

 a seeding with it and infect the subse- 

 quent apparatus through which it 

 flows to the detriment of the milk of 

 proper temperature following it. 



The charts showing the records of 

 the temperature of the cold milk in a 

 pasteurizing apparatus, must show the 

 time and temperature maintained 

 through the run, the temperature to 



which the milk was cooled during the 

 run and the time of the finish of the 

 run. 



To check up the holding period of a 

 milk run through a continuous flow 

 pasteurizing apparatus from the, chart 

 records, the elapsed time after the time 

 of the discharge of milk from the 

 heater to the holders, and the time of 

 the first discharge of milk from the 

 holders, will be the theoretical holding 

 time. If the flow of milk to the ap- 

 paratus is uniformly maintained 

 throughout the run, the theoretical 

 holding time for the run will be the 

 same ; if, however, after the complete 

 apparatus is in operation and the the- 

 oretical holding time is established on 

 the chart record, the pump speed is 

 accelerated or the flow of milk in- 

 creased by any means, the holding 

 time will be shortened, arid effective 

 treatment lessened. Therefore, it is 

 of importance to install the pasteuriz- 

 ing apparatus in such a manner that 

 the flow of milk per hour cannot be 

 increased beyond the rated capacity 

 of the apparatus. 



The time of emptying the holding 

 tanks can be checked by noting the 

 elapsed time between the finish of the 

 continuous flow from the holders, as 

 shown on the holder chart, and the 

 time of finishing the run of cooling the 

 milk, as shown on the cooler chart. 

 If the holding time of the milk 

 through the run cannot readily be de- 

 termined from the charts for any rea- 

 son, the quantity of milk pasteurized 

 should be taken from the plant rec- 

 ords and the quantity of milk run 

 through per hour determined, comput- 

 ing the time between the starting and 

 finish of the holding operation, deduct 

 from this any time lost owing to in- 

 terruption to the flow (these interrup- 

 tions will appear on the charts) and 

 check the quantity of milk per hour 

 actually run through the apparatus 

 with its rated capacity. 



