HANDLING, SHIPPING, AND STORAGE OF BARTLETT PEARS. 11 



namely, how soon after the removal of the fruit from the tree can the 

 pears themselves be cooled to 30° F. or below? If the fruit after 

 picking can be reduced to this temperature in 24 to 36 hours, there 

 is no doubt that such treatment will be of great advantage in the ship- 

 ping of the fruit. 



Such results can be attained, however, only by having a very large 

 refrigeration capacity in proportion to the quantity of fruit handled. 

 Marked success has been attained by precooling in the Yakima Val- 

 ley in Washington, and an outline of the methods followed there will 

 indicate the procedure that has given greatest success in handling 

 Bartlett pears. 



The rooms in which the pears are to be placed are cooled to below 

 28° F., in many cases the temperature being reduced to 10° to 20° F. 

 before the fruit is brought in. The fruit is taken to the storage house 

 in lug boxes immediately after picking. As it cools, the room tem- 

 perature rises, but the air in the rooms is kept down to 28° F. or is 

 again reduced to that temperature as quickly as possible after the 

 fruit is placed in the room. After 36 to 48 hours at 28° F. the fruit 

 is removed to a warmer room, held at about 40°, where it is graded, 

 packed, and quickly returned to the 28° room. In most cases the 

 fruit is not in the packing room for more than 30 minutes to an hour, 

 and it is probable that the temperature of the fruit itself does not rise 

 more than 1 or 2 degrees during this time. The fruit is shipped at 

 any time after packing, from immediately thereafter up to a month 

 later. The bulk of the crop, of course, is forwarded at once. 



Pears cool very slowly when taken into cold storage, and at least 

 24 hours will be required to reduce the unwrapped fruit in boxes to 

 the desired temperature. If the fruit is wrapped before cooling or if 

 the boxes are closely stacked in the rooms, a much longer time is re- 

 quired, due to the insulating effect of the paper and the reduced 

 aeration in the boxes. In this connection the need for an armored 

 thermometer that can be inserted in the fruit itself, by means of 

 which its temperature can be determined, should be emphasized. 

 Low temperatures retard the ripening processes in the pears only 

 after the fruit itself reaches that lower temperature. This is very 

 often a considerable time after the air is at the desired temperature; 

 this is doubly true if the fruit'is wrapped. 



Very careful tests have been made of the rate of ripening of 

 Bartlftt pears at different temperatures by measuring the carbon 

 dioxid given off by them. It has been found that they ripen about 

 twice as rapidly at 37° F. as at 30° F. It is not possible to stop en- 

 tirely (he ripening of the fruit ;it any temperature above the freezing 

 point, which in Bartlett pears has been found to be between 27° F. 

 and 28° I''. However, at temperatures under 30° F. the fruit ripens 

 so slowly licit :i number of days at this temperature makes only a 

 slight diff'-n-iH-f in the t irnc the pears will hold up after removal from 

 cold storage. 



