MILK-PLAXT OPERATIOlSr. 23 



economy of using machinery is even more obvious than at that time, 

 owing to the fact that the cost of labor is so much higher than it 

 was m 1914. According to Figure 16, hand washing was more 

 economical than the automatic machine for plants washing less than 

 1,200 bottles daily, while the brush washer was more economical 

 than the automatic machine for plants washing up to about 2,300 

 bottles daily. According to Figure 15 hand washing is not economi- 

 cal for plants even of the smallest size, and the brush washer is 

 economical only for plants washing 1,600 bottles or less. 



In the illustrations it can be seen that in order to determine ihs 

 relative economy of the various methods of washing bottles the cost 

 of the machine and of labor in the particular locality must be care- 

 fully considered. The variation in the efficiency of different men 

 must be taken into account also. 



Another factor to be considered in determining which type is the 

 most economical is the time required to wash a given number of 

 bottles. Time in the milk plant is an important factor, and methods 

 of operation must be followed that will provide for the work being 

 accomplished in a definite time. It will be noted that at 56 plants 

 using automatic washers the average number of bottles washed per 

 hour was 4,628, while at 49 plants using brush washers the average 

 number of bottles washed was only 928. Thus if a plant has, let us 

 say, 5,000 bottles to wash it will take, according to these figures, 

 more than five hours with a brush washer, while the work could be 

 done with an automatic machine in a little more than an hour. It 

 is generally desirable at medium-sized or small plants that the bottle 

 washing take no more than half of the day, so that the men doing 

 this work can be emplo3'ed elsewhere during the remainder of the 

 day. For example, one set of men may wash the bottles in the morn- 

 ing and bottle milk in the afternoon. In that case the bottle washing 

 must be done in from three to four hours. It is therefore necessary 

 at such plants to select a bottle washer which will permit the work 

 to be done in this time, and as a general rule it is to the advantage 

 of the dealers handling this number of bottles to use the automatic 

 rather than the brush washer. Wliere only one or two men are 

 washing bottles and they are not suitable to help in filling bottles, 

 it may be economy to keep them washing bottles for the greater 

 part of the day; in that case a brush washer would be satisfactory, 

 provided they could wash all the bottles with it in from six to eight 

 hours. In any case, however, thoroughness is of first importance, 

 and such methods should be used as will result in the most thorough 

 cleansing and sterilization. 



In the discussion of labor costs in bottling milk and in wasliing 

 bottles, no attempt has been made to include all t}-pes of machinery. 

 The studies made include the more common types in use, although 

 other more recent types are on the market. 



INSPECTION OF BOTTLES. 



Wliile the large automatic pressure washers give satisfactory residts 

 in general, there are always some bottles that will not be thoroughly 

 cleaned._ Bt)ttles that have stood for several days, or those in wliicli 

 the casein of the milk has dried, \\i\\ pass through the machines with- 

 out being properly cleaned. It is necessary that all such bottles be 

 culled out and washed with a hand brush before thev are sent tlu'ousrh 



