16 BULLETIN 973, tJ. S. DEPARTMENT OF AGRICULTURE. "J 
WASHING BOTTLES. 
The milk bottles should be washed in ample time to be thoroughly- 
cool before they are filled with milk. If the bottles are not cool, 
the temperature of the milk put into them is raised. This means a 
waste of refrigeration, and an increased development of bacteria is 
possible. At many plants bottles are washed in the morning and 
filled in the afternoon. Great care should be taken to see that the 
bottle washer is always in working order, for if the bottles are not 
properly cleaned and sterilized the pasteurization of the milk may 
be of little value. 
Fig. 13. — Automatic bottle washer. An average of 1,002 bottles per man-hour was washed at 56 
plants using machines of this type. 
In case a brush washer 5 is used, the brushes should be changed 
before they become worn, and the washing water should be changed 
often during the day. Great care must be taken to see that the 
rinsing and steaming device of the machine is in good working 
order at all times. Each bottle should receive a strong jet of rinsing 
water and then a jet of steam for at least 45 seconds. Jet openings 
should be free from obstructions. After the bottles are washed 
they should be kept in a cool, clean place until wanted for filling. 
If the bottles are inverted in the cases, there is less chance for con- 
tamination. It is a good plan to use special cases at the washer and 
transfer the bottles, after they are washed and steamed, to clean, 
dry cases. If the same cases that are used in the washer are used 
also to store the bottles, there will be a constant drip from each case 
into the case below, and these cases also soon become soggy. If 
5 For a description of types of bottle washers see U. S. Department of Agriculture Bulletin No. 890, 
"Milk- Plant Equipment." 
