REMOVAL OF SPRAY RESIDUE FROM APPLES AND PEARS 11 



discarded, thereby keeping the recirculated rinse water relatively 

 free from contamination.- Mere rinsing of the fruit in boxes in a 

 tank, even if some fresh water is added, is not generally so satisfac- 

 tory as those methods heretofore mentioned. In any event, it is 

 desirable to have at least 3 gallons of water available for each box 

 of fruit washed. 



In washing machines the exposure to the rinsing should generally 

 be at least half as long as the exposure to the acid in the equipment 

 commonly used. Constant attention should be given by the operator 

 to keep the rinsing section in optimum operating condition. 



METHODS OF DRYING 



Reasonable drying of the fruit seems essential to facilitate pack- 

 ing and to insure proper storage life to the fruit. The drying be- 

 comes of less importance with sound fruit as the washing and rinsing 

 become more efficient and satisfactory. 



The most successful drying method under observation in 1927 

 was the one employing forceful air blasts suitably directed to sweep 

 the moisture from the fruit by mechanical pressure. The different 

 types of cloth drying agents were fairly satisfactory, especially 

 the draper-towel arrangement with pieces of toweling hanging down 

 and passing over the fruit as it moved forward on the conveyor. 

 These were continually passed through a wringer to remove excess 

 moisture, and in this respect they were superior to the cloth roller 

 wipers also commonly used for dry cleaning. The cloths on the 

 rollers had to be frequently renewed if they were to function prop- 

 erly as drying agents. 



The brush driers also under observation in 1927 were not generally 

 efficient even when surrounded by heated air, especially when they 

 were in tightly closed chambers. 



Drying was more easily done early in the season or during the 

 middle of the day when the relative humidity of the air was lower. 

 This factor materially influences the drying of fruit in stacked 

 boxes, as it is done in most dipping methods, and also affects the 

 efficiency of any drying schemes designed to evaporate the moisture 

 from the fruit. The space requirements of driers, if thejr are to be 

 efficient, are also frequently difficult to provide under packing-house 

 conditions in the Northwest. 



The polishing of apples after drying is not generally essential if 

 they are cleaned properly, although some packers express a pref- 

 erence for it. Any additional handling of the fruit, such as occurs 

 when apples are passed through a polisher, simply increases the risks 

 to the storage life and condition of the fruit and should be well 

 justified before it is put into practice. 



APPARATUS AND METHODS FOR DETERMINING ACIDITY 



A description of the apparatus and methods for the determination 

 of acid strength is presented herewith. 



Any careful washing-machine operator can determine the strength 

 of the acid in the acid tank and maintain the desired concentration. 

 The following equipment will be necessary : 



One 10 c. e. bulb pipette; one 10 c. c. measuring pipette (graduated in 0.1 c. c.) ; 

 one 3-ounce bottle; standard sodium bicarbonate, 23 gram to 1,000 c. c, con- 

 taining methyl orange indicator. 



