January, 1921 



BETTER FRUIT 



Apple Scald — Its Cause and Prevention 



Delivered before the International Apple Shippers' Convention by Charles Brooks 



(Continued from December Number.) 



ANOTHER condition that makes it dif- 

 ficult to solve the scald problem by 

 means of storage ventilation is the fact 

 that it does not suit to ventilate at the 

 time the apples need it most; that is 

 during the first weeks of storage. The 

 outside air is likely to be warm at the 

 time the plant is running at full ca- 

 pacity lo bring down the temperature 

 of the incoming fruit and the managing 

 force fully occupied with other duties. 

 Some storage plants that make a point 

 of throwing their windows and doors 

 open do not begin this ventilation till 

 the last of December or first of Jan- 

 uary. This is too late to be of any 

 benefit to the early scalding varieties 

 as the time for the remedy is passed 

 several weeks before the scald actually 

 appears. Grimes apples do not usually 

 become scalded until after they have 

 been in storage 12 lo 14 weeks. A single 

 really thorough changing of the air 

 around the apples themselves at the 

 end of 6 or 7 weeks will delay the 

 time of scald appearance more than a 

 month but an equally good ventilation 

 at the end of 8 or 9 weeks will have 

 little or no effect upon the time that 

 scald will appear. The abnormal con- 

 ditions have then prevailed too long; 

 the stage is already set for the scald 

 that will become evident several weeks 

 later and remedies are of no avail. 



Some apple communities have adopt- 

 ed a method of delayed packing that is 

 of considerable value in scald preven- 

 tion. The apples are stored in open 

 picking crates just as they come from 

 the tree and are later transferred to a 

 special packing room, run over a grader 

 furnished by the storage organization 

 and packed in boxes and barrels ready 

 for the market. The open crates secure 

 quicker cooling and better aeration 

 while in the storage room and the thor- 

 ough airing given in sorting and pack- 

 ing sends the fruit back into storage 

 sufficiently freed from harmful gases 

 to add several weeks to the storage life 

 of the scald susceptible varieties. 



One of the things that plays a very 

 important part in determining the ef- 

 fects of any storage ventilation is the 

 manner in which the barrels or boxes 

 are stacked in the room. Some storage 

 houses stack their boxes solid but most 

 of them use strips between the layers 

 and leave space between the stacks. A 

 large number of storage houses leave an 

 open space around the walls and some 

 o( them, particularly those in the West, 

 hold the fruit 2, 4 or even 6 inches from 

 the floor by means of scantling or some 

 form of false floor. All of these things 

 that tend to give openness to the stack 

 are valuable for both refrigeration and 

 ventilation and all are of value in scald 

 control. We have not found, nor been 

 able to develop any commercial stor- 

 age condition that will completely han- 

 dle the scald problem. The apples in 

 the middle of the slacks do not get the 

 fresh air and are but little benefitted 

 by storage ventilation. In a test made 



in a storage room that was opened fre- 

 quently it was found that the apples in 

 the center of the stack became scalded 

 four weeks earlier and finally devel- 

 oped about three times as much scald as 

 those near the doors. 



Air-cooled storage houses often se- 

 cure as good or better results in scald 

 prevention as the commercial plants, 

 the bad effects of the higher tempera- 

 tures being offset so far as scald is con- 

 cerned by the good effects of the ven- 

 tilation. An air-cooled plant that main- 

 tains a fall temperature of 40° to 45° 

 may be able to bring its apples through 

 fairly free from scald; but if a com- 

 mercial storage plant with its tightly 

 closed rooms should be compelled to al- 

 low its temperature to remain at such 

 a high point for a few weeks in the fall 

 because of a shortage of refrigeration 

 or a poor distribution of the warm fruit 

 the condition would result in a great 

 increase in scald later in the storage 

 season. 



One of the most important places for 

 ventilation is the packing house. For- 

 tunately most packing houses are really 

 sheds and cannot be closed. The free 

 circulation of the night air is particu- 

 larly important both on account of its 

 coolness and the ventilation secured. 

 Large closely stacked piles of fruit in 

 the packing shed may produce distinct- 

 ly harmful effects, especially if the top 

 and front of the pile is continually 

 passed along to storage and the bottom 

 left undisturbed for a number of days. 

 The character of the packing plays a 

 very important part in ventilation and 

 is therefore a determining factor in 

 scald occurrence. Apples scald far less 

 in boxes, hampers and ventilated bar- 

 rels than they do in the usual commer- 

 cial barrels. This is especially true 

 where the storage room receives at 



Page 11 



least a small amount of ventilation. We 

 have had particularly good success 

 with the ventilated barrels. In most 

 of our storage experiments these were 

 prepared by cutting 15 holes or slits 

 (each % inch by 4 inches) in the staves 

 of the ordinary apple barrel. Reducing 

 the total area of the holes by one-half 

 gave much poorer results. Apples 

 packed in the above ventilated barrels 

 have usually had the scald reduced to 

 one-half or one-third the amount on 

 similar apples in the usual commercial 

 barrels and the disease has appeared 

 on the fruit three to four weeks later. 

 The ventilated barrel shows up to the 

 best advantage in cases of delayed stor- 

 age. Apples in ventilated barrels de- 

 layed a week to ten days in an open 

 packing house will usually show less 

 scald than those in tight barrels that 

 are stored immediately. If the apples 

 are fairly green at picking time a few 

 days delay in ventilated barrels may 

 actually improve the keeping quality of 

 the fruit at least so far as scald is con- 

 cerned. 



While we were trying to find out 

 what uses could be made of ventilation 

 in scald prevention we were also mak- 

 ing experiments to determine what the 

 harmful substances were that needed to 

 be removed from the apple for if we 

 could only find this out we might be 

 able to absorb them in the package or 

 in the storage room and obviate the 

 necessity of renewing the air. Conver- 

 sations with cold storage men revealed 

 the fact that many of them were of the 

 opinion that high humidity in the stor- 

 age room was favorable to scald. Ex- 

 periments were therefore made to test 

 this theory, apples being stored in at- 

 mosphere having various percentages of 

 moisture. With 50 per cent relative 

 humidity the apples withered badly yet 

 they scalded if the air was not stirred. 

 With 70 per cent relative humidity 

 some varieties withered and all scalded 

 if the air was stagnant. The scald was 



u 



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Bloedel < ^^^ > Donovan 



101 8 White Blag. Seattle U.S.A. 



VERTISERS MENTION BETTER FRUIT 



