REMOVAL OF SPRAY RESIDUE FROM APPLES AND PEARS ( 



two hours is essential under ordinary commercial conditions. Some 

 packers discard the old cloths and replace them with new ones; 

 others launder or steam clean the soiled cloths before using them 

 again. 



A suction arrangement by which loose dust and residue particles 

 may be constantly removed from the machine will help materially 

 in keeping the equipment clean. 



The relative efficiency of brush cleaners is determined largely by 

 the cleanness of the brushes, their ability to retain their original 

 resiliency, their proper adjustment in the machine, and the rate 

 at which the fruit moves through the machine. 



With the oscillating-brush type the resiliency of the bristles is 

 essential to efficient cleaning if injury to the fruit is to be avoided. 

 The removal of particles of dust or residue by suction or by air 

 blast is very helpful in prolonging the efficiency of relatively clean 

 brushes. Brushes should be taken from the machine for cleaning 

 several times a day. The use of some solvent on a sponge or cloth 

 pressed against the brushes whije they are in motion is not sufficient ; 

 soap and hot water or gasoline are usually available and are effective 

 materials for cleaning the brushes, especially if applied with a 

 scrubbing brush. At least one extra set of brushes for replacement 

 while the used ones are being cleaned should be provided. 



Under commercial handling and storage conditions there has been 

 practically no loss from excessive wilting of apples following dry 

 cleaning. However, there is a possibility of loss from slack packs 

 if such apples are held in storage with a low air humidity. The best 

 relative-humidity conditions for apple storage are found at about 

 85 per cent. 



With pears there is considerably more clanger of .wilting after dry 

 cleaning. This is especially true if the handling by the cleaner is 

 rough and leads to some discoloration of the surface of the pears. 

 Tender-skinned varieties, such as Anjou and Cornice, are particularly 

 susceptible. 



CLEANING FRUIT EY SOLVENT METHODS 



The washing methods in commercial use during the past two sea- 

 sons may be divided into two groups on the basis of the solvent 

 employed: (1) Those using hydrochloric acid and (2) those using 

 alkaline materials. Although the acid-solvent methods were used in 

 most cases, the cleaning efficiency of both types have been studied. 

 Observations have been made on seven typical methods using acid 

 solution while cleaning all of the important commercial varieties of 

 apples and pears. The fruit was obtained from a large number of 

 orchards in the several districts where a variety of spray practices 

 had prevailed during the growing season. 



The solvent methods studied were the following: (1) Diffused 

 spray, (2) forceful-jet spray, (3) flood washer, (4) flotation, (5) 

 combination of overhead diffused spray and flotation, (6) tank dip- 

 ping in boxes, (7) deep submersion, and (8) alkaline-solution washer. 



The following is a brief description of the mode of operation of 

 the various methods under observation : 



DIFFUSED-SPRAY WASHER 



The fruit was carried forward on a rod conveyor while being 

 sprayed with the cleaning solution from above and below by means 



