REMOVAL OF SPRAY RESIDUE FROM APPLES AXD PEARS 15 



in commercial machines which plunged the apples to a depth of 5 or 

 •3 feet in hydrochloric acid for periods as long as five minutes. 



CHEMICAL INJURY AT THE CORE 



The varieties most seriously affected b} T core injury were those with 

 open calyx tubes which admit washing solutions and spores of rot 

 fungi to the core region. Penetration of washing solutions may be 

 detected eYen in the absence of core rots by the injury of the core 

 tissues. This injury is characterized by a brownish discoloration and 

 drying of the tissues. 



The tendency to the production of open calyx tubes varies in 

 different orchards and is greatly influenced by spring frosts. Where 

 the apples were submerged in boxes, more than 50 per cent of those 

 with open calyx tubes developed core injury, but where the apples 

 were sprayed with washing solutions the core injury was negligible. 

 The admittance of washing solutions to the core and the injury 

 produced thereby is not so significant in itself, but when the spores of 

 rot organisms may be introduced at the same time it becomes a 

 matter of great importance. 



The severity of the injury from core penetration is influenced to 

 a considerable extent by the strength of the cleaning solution used. 

 Hydrochloric acid used at the rate of 3 gallons per 100 gallons of 

 water causes much more penetration injury with apples having open 

 calyx tubes than when used at the rate of 1 gallon per 100. 



It is apparent, therefore, that in using submersion methods some 

 varieties of apples can be washed without serious danger, but in- 

 discriminate use with varieties having open calyx tubes may result 

 in considerable loss, particularly if the fruit is in motion or the 

 exposure is prolonged. The deeper the submersion and the stronger 

 the solution the greater the risk involved. 



Xo great extent of penetration has been noted when the fruit was 

 floated on the surface of the cleaning solution. When the flota- 

 tion method is used, however, the fruit should travel through the 

 machine in a single layer, and the duration of the treatment should 

 not be extended beyond the time required for cleaning. Occasional 

 shallow submersion just beneath the surface of the solution for a 

 few seconds does not seem to cause much penetration to the core. 



ROT-PRODUCING SPORES AND MOISTURE 



The accumulation of spores of rot-producing fungi in washing 

 solutions was studied in a large number of machines throughout the 

 season. The number of viable spores of the different organisms 

 present in these solutions varied (1) with the quantity of fruit 

 washed, (2) with the condition of the fruit (.sound or infected), (3) 

 with the manner of application of the washing solution, and (4) 

 with the length of time the spores were in contact with the solution. 



Hundreds of decay-producing spores are commonly found on a 

 single sound apple as it comes from the orchard, whereas a rotted 

 apple may bear enough infective material to destroy several car- 

 loads; hence the accumulation of spores in the washing solution is 

 directly proportional to the number and condition of the apples 

 washed. Decayed apples should be sorted out before they pass into 

 the cleaning machines. 



