RHLZOPUS EOT OF STRAWBERRIES IN TRANSIT. 



17 



negative results, indicating that any increase of infection from this 

 source is relatively unimportant. 



In investigating the effect of drying the fruit after washing, a 

 number of experimental shipments were made, the fruit being han- 

 dled in the same manner as in the washing experiment already de- 

 scribed except that part of the berries in each shipment were packed 

 wet, while the remainder were partially dried, usually by exposure 

 to direct sunlight for a few minutes. The results were conclusively 

 in favor of packing the fruit wet. Taking the average of, all these 

 experiments, it was found that drying berries washed in clean water 

 had reduced the proportion of sound fruit 36 per cent. Among those 

 washed in dirty water the reduction caused by drying was even 

 greater — 43 per cent. 1 Table III summarizes the results of all ex- 

 periments on drying the berries after washing. 



Table \\\.— Effect of drying strawberries after washing. ' 





Packed without 

 drying. 



Packed after drying. 



Treatment of fruit, if any. 



Number 

 of berries. 



Sound 



after 



arrival. 



Number 

 of berries. 



Sound 



after 



arrival. 





1,939 



2,886 

 650 



Per cent. 

 50 

 48 

 33 





Per cent. 





2,881 

 1,144 



30 





19 







In no case were these results reversed, though they differed in degree 

 in the various shipments. These variations were correlated with 

 differences in temperature when the berries were packed, the com- 

 parative benefit of wet packing being greater in those^ shipments pre- 

 pared on very warm days than in those packed during cool, cloudy 

 weather. Drying the fruit, even in the shade, proved injurious, 

 though less so than exposure to direct sunlight. 



The laboratory experiments already cited indicate that the rate of 

 growth of Rhizopus nigricans increases very rapidly with the rise of 

 temperature above 10° C. (50° F.). When infected berries are held 

 for a few hours at a relatively high temperature, for instance, 30° C. 



1 Smith and Goodman, of the Department of Agriculture of British Columbia, have 

 conducted experiments upon the fanning of strawberries before shipment. They report 

 (Winslow, R. M. Report of horticultural branch, 1914. In 8th/9th Rpts. Dept. Agr. 

 [Brit. Col.], 1913/14, p. 84. 1915.) that berries dried for an hour in a strong cur- 

 rent of air from an electric fan carry to market in better condition than those shipped 

 even slightly wet. Though not so mentioned in their report, this operation would have 

 the effect of lowering the temperature of the berries quickly and considerably by increas- 

 ing the rate of evaporation of the water from their surfaces. It would thus be, in effect, 

 a precooling process, allowing the berries to be placed in the car at a relatively low 

 temperature if loaded at once ; if, after fanning, however, the fruit were hauled several 

 miles to the station during hot weather, much of the benefit of rapid drying would be lost. 



