TRANSPORT AND STORAGE OF FOOD 433 
attempt to control its life-history. English apples want to go their own 
way, live normally for a few months and no more. When the process of 
ripening is retarded by cooling or in some other way, the chemical changes 
are apt not only to be slowed down, but to depart somewhat from the 
normal; abnormal products may then be formed, which, among other 
things, alter the flavour of the apple. Now, no one would wish to purchase 
a long-stored English Cox’s Orange Pippin, which possessed the flavour of 
a very inferior variety, on the score that the apple was good. Clearly, it is 
not sufficient merely to keep an apple so that it is good as food ; the storage 
must be such that the product is both palatable and as near as possible in 
all its properties to those of fresh, unstored fruit. 
Since the changes which take place in the apple are, broadly speaking, 
chemical changes, the fact that cold prolongs the life of an apple is not 
surprising, for most chemical changes go on more slowly the lower the 
temperature. Let us consider the question of temperature first. 
Effect of Temperature —It has long been known that the life of apples is 
prolonged by storage in cold rooms with appropriate ventilation, and natur- 
ally the first researches aimed at obtaining data connecting the life of the 
apple with the temperature of the air in which the apple lived. 
Roughly speaking, an average apple respires about five times as fast at 
a temperature of 70° F. as it does at 35° F. The explanation of the preserva- 
tive effect of cold is apparent ; the lower the temperature, the less does the 
apple lose its substance, and the longer is its probable life. I have already 
mentioned that the apple must not be frozen or it is killed; provided, 
however, that the apple is not killed, it appears that the lower the tempera- 
ture the longer is the life of the fruit. 
But there are other factors. Apples vary in their tolerance of cold. It 
is well known that for about nine months of the year our table apples are from 
overseas, yet some of these are gathered at the same time as our own, The 
difference is that many of the overseas apples can be successfully stored in 
cold chambers for much longer periods than English apples: for instance, 
English apples do not do so well in cold storage as those from N.W. America, 
where the climatic conditions, higher temperature, lower humidity, and 
abundant sunshine appear to confer greater tolerance. But apart from 
differences of this kind, due to large differences in the conditions of the 
growth of the fruit, varieties in the same country, even in a small country 
like ours, differ very much in their tolerance of cold. For instance, re- 
ducing the temperature from 37° to 34° F. may lengthen the storage life of 
one variety of apple by, say, 25 per cent., but it may actually shorten that 
of another variety by the same amount. In the latter case life is ended, not 
as it normally is, by fungal rotting, but by physiological disorder directly 
caused by the cold and known as ‘ low-temperature breakdown.’ 
Let me refer to the figure again. The two parts BC and CD are two 
stages in the life of the apple, and the reaction of the apple during the BC 
part of its life is different from that of the CD portion. In the case of 
Bramley’s Seedlings, the fruit is peculiarly susceptible to internal break- 
down when subjected to cold during the BC portion of its life, but for 
the CD portion it is only slightly susceptible to internal breakdown, but in- 
creasingly liable to attack by fungi. ‘These two types of disease are of very 
considerable commercial importance, and it was necessary to determine 
experimentally the optimum temperature of storage. ‘This has been done. 
It is of interest to note that severe injury to the skin of an apple, as by cutting 
it in half, is followed by an increased output of carbon dioxide. 
Effect of the Atmosphere.—Since the apple is alive, taking in oxygen and 
giving out carbon dioxide, it appears safe to conclude that the composition 
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