18 BULLETIN 531, U. S. DEPARTMENT OP AGRICULTURE. 



(SG° F.), the fungus develops so rapidly in their tissues as to cause 

 them to collapse. The growth of the fungus may be checked by 

 lowering the temperature, but with ordinary refrigeration growth 

 will not entirely cease, and it may continue sufficiently to cause the 

 berries to soften in transit ; it will in any case resume rapid develop- 

 ment whenever the temperature is again raised, as when the berries 

 reach their point of destination. If infection has occurred, a dif- 

 ference of a few degrees in the temperature of the berries, main- 

 tained for several hours, will make a decided difference in the length 

 of time before rot becomes apparent. This accounts for the harmful 

 effects of drying the berries. 



Dry berries remain at air temperature until placed in iced cars or 

 other refrigerated containers, usually a period of several hours. Dur- 

 ing part of this time the crates are often exposed to the sun or covered 

 with a dark cloth. When berries are immersed for a few seconds in 

 water their temperature is lowered somewhat. Subsequent evapora- 

 tion from their surfaces results in still further cooling. If they are 

 packed immediately after washing, evaporation continues slowly and 

 exerts a cooling effect for several hours, usually until the berries are 

 placed under refrigeration. When berries are being loaded into cars 

 in the afternoon, several hours after picking, the difference in tem- 

 perature between unwashed fruit and that packed wet can be readily 

 felt with the hand. When, after washing, the berries are dried for a 

 few minutes in the shade, the water evaporates before packing, and 

 they lose the continued cooling effect of prolonged evaporation. If 

 they are exposed to direct sunlight there is the added disadvantage of 

 a further rise in temperature. The beneficial effect of packing the ber- 

 ries wet is greatest, of course, when the temperature of the air is 

 highest. 



Professional packers claim that berries are softened by washing and 

 must be handled with great care to avoid bruising if packed while 

 wet. This probably is true, but it is more than compensated for by 

 the cooling of the fruit. 



Exposure to sunlight, unless very brief, has the further undesirable 

 effect of giving the berries a dull appearance. Heating unwashed ber- 

 ries by exposure to the sun increases rot, but not so markedly as with 

 washed berries. This is illustrated by an experimental shipment pre- 

 pared at Lakeland, Fla., on the morning of March 22, 1916, a clear, 

 warm day. Sound berries of the Missionary variety were used. After' 

 treatment they were packed by a professional packer, carried to the 

 railroad station at noon, and shipped to Washington in a ventilated 

 crate without refrigeration. They were three days in transit. Their 

 condition on arrival is shown in Table IV. 



