fruit, the cost of refrigerating culls, and the possibility that scald 

 might develop on apples not protected by oiled paper. 



Kind and Temperature of Washing Solutions 



Most experimentation (5, 7, 10, 11, 12, 16, 17, 25) has indicated 

 that mild washing to remove spray residue does not increase subse- 

 quent decay by blue mold {2, IS, 15) and other fungi. On the con- 

 trary, however, Pentzer (19) and Streeter and Harman (27) found 

 greater decay in washed Mcintosh apples and Green (9) reported 

 that of five varieties studied only Jonathan showed increased decay, 

 chiefly blue mold, after washing. Fisher and Keeves (6) stated that 

 washing with proper equipment and due attention to sanitation did 

 not impair the market value or the keeping quality of apples. 



Little work has been done on the comparative effects of acid, 

 alkaline, and dual washings on the subsequent development of decay. 

 Overley, Overholser, and St. John (18) reported in 1934 that in pre- 

 liminary experiments apples washed in sodium silicate solution devel- 

 oped less rot than comparable fruit washed in hydrochloric acid. In 

 1938 Haller and others (11), however, found no significant difference 

 between the effects of these solutions. 



In 1938 all the apples were washed with the same solutions (table 

 4). In most lots the washed fruit had more lenticel infection and 

 total decay than the unwashed; the infections at other points, how- 

 ever, did not seem to be definitely related to the washing treatment. 

 In five of the eight possible comparisons a slightly larger percentage 

 of the unwashed than of the washed fruit had infections that did not 

 start at lenticels. 



In 1939 and 1940 the apples were washed with different solutions 

 at the temperatures given in table 5. The most severe treatment 

 (silicate at 110° F. plus acid at 100°) caused serious injury in the form 

 of small skin cracks largely in and around the calyx basin. The less 

 severe dual-process treatment and the acid wash at 105° resulted in 

 moderate injury, whereas very little damage was caused by silicate 

 at this temperature. At 80° neither acid nor silicate was visibly 

 harmful. The work of Smith, Ryall, and Cassil (26) indicated, 

 however, that a temperature of at least 100° is necessary if the spray 

 is heavy. 



In both 1939 and 1940 more lenticel infection and total decay oc- 

 curred in fruit cleaned by the dual-wash process and by hydrochloric 

 acid than in comparable unwashed apples. Fruit washed with sodium 

 silicate alone at 80° F. was not consistently more susceptible than 

 unwashed fruit. In the single comparison of apples washed with 

 sodium silicate at 105° and unwashed fruit there was slightly more 

 decay at lenticels of the former. In general, the susceptibility, of the 

 fruit was directly related to the severity of the washing treatment. 

 Even where visible skin cracks did not occur, the washing treatment 

 was found to increase the susceptibility of the lenticels to infection. 



Size of Spore Population 



The early work of Heald, Neller, and Overley (15) showed that the 

 amount of decay in punctured Jonathan apples varied directly with 

 the number of blue mold spores in the washing solution. Later 

 Baker and Heald (2) found also that lenticel infection in several 

 varieties of apples was directly related to the spore load of the fruit. 



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