STORAGE OF FRUIT.

Otago Daily Times, Issue 20287, 21 December 1927, Page 10

STORAGE OF FRUIT.

DR KIDD’S INVESTIGATIONS

TEMPERATURE PROBLEM, DISCUSSED.

(Special ro Daily Timhs.) WELLINGTON, December 20,

The report embodying the conclusions arrived at by Dr E. Kidd, of the Cambridge Low Temperature Research Station, as the result of his recent investigations in New Zealand as to the application of scientific research to the storage, handling, and transport of the Dominion’s fruit was released for publication to-day. From what he nad seen and heard, he states, the actual conduct of the storage industry in New Zealand appeared to be well on a par with that of other countries. Insufficient attention, he thought, had been paid to the effect of the storage tem. perature upon the quality of fruit after it was removed from store and came upon the market. The question of th e depreciation of fruit between the time it left the store and the time it reached the consumer appeared to be especially worth studying in those cases in which fruit was cleared from the store as being already on the verge of internal breaking down. Dealing 'with air movement, humidity of the storage atmosphere, and ventilation, Dr Kidd said that there appeared to be far less firm a grasp of what was known as to the effect of those factors upon fruit in storage. Broadly speaking, fruit should not be allowed to lose more than 5 per cent, of its weight by evaporation during the whole period of its storage, and the air movement and humidity should be adjusted to that end. “ Much of the fruit that I have seen after five or six mouths’ storage,” says Dr Kidd, “ has struck me as being excessively wilted and shrivelled from the commercial point of view. A storage life of nine months, I am told, is the object to be aimed at by the apple and pear industry in New Zealand. In the circumstances one of the most important questions now requiring solution is whether the present excessive wilting, shrivelling, and loss in weight is in reality essential to the avoidance of internal breakdown or flesh collapse.” The form of damage known as superficial scald was probably best controlled by the use of air wrappers or shredded oil paper packing material rather than by reliant on air movement. In 'eference to ventilation Dr Kidd suggests that a wet battery or brine spray in the air circuit must to some extent accomplish the same object as was effected by periodic ventilation with fresh air from outside. In the course of his general conclusions Dr Kidd suggests that a certain amount of technical research of an Imperial character is needed in order to systematise information for the guidance of cool storage engineers in regard to the optimum storage temperatures for different varieties of New Zealand apples and pears and soil variants of these varieties, and also-_ to determine whether the excessive wilting now striven for with the object of avoiding internal breakdown is in reality necessary. It is suggested that the Department of Scientific and Industrial Research should undertake this work. In general. Dr Kidd was impressed with the inadequacy of the instruments milable for the effective control of physical conditions. At least two thermometers bould be keptin the storage chamber in positions corresponding to the extremes of temperature distribution, and one recording thermometer. periodically tested, bould oe kept in each chamber. It was further suggested that the Department of Scientific and Industrial Research should devote some attention to the possibility of devising a thermometer suitably lagged to show temperature readings comparable to that of the temperature of the fruit ; n an exposed case on the outside o. a stark. In any case eacli engineer should be provided with a skewer thermometer, suitable for taking fresh temperatures as for humidity. The question of a suitable instrument must be regarded s an urgent matter to be referred to he Research Department. The wet and dry bulb equipment that some stores possessed was most inadequate, and it might be taken that no reliable records of humidity had been kept as yet. “ For the control of physical conditions,” continues Dr Kidd, “ the type of equipment which our knowledge at present points to as being the most efficient embodies the following features ;—(1) Cooling by forced air circulation over a bat. tcry of brine or duct experimental in a separate battery chamber, (2) independent control of humidity by a brine spray, the concentration of which may be varied, or a system of reheating the air after supercooling it in the battery chamber; (3) (loor to ccilint, circulation with a reversible fan. Manv of the cool I stores visited did not appear In me to be run as economically as they might be. '

With rcfcrencj to (lie mcchanica.l efficiency of stores. Dr Kidd stater tiiat it miirlit prove useful from a number

points of view to determine ‘he sugar arid, starch, nitrogen, etc., content of different lines of varieties of New Zealand apples and pears and the changes that occur in tht relative ornportions on flic chemical constituent s of the apple during growth, maturity, -nd smcccnce.

Thi- earth is like a steam boiler pn-kcl'-d by a layer of asbestos. The centra! portion, whatever its nature, occupies about throe-f|iiarters of the earth's radius, with an outer shell of rock l -, it will take at least 100,000.000.H0G years for the internal temperature to fall to halt of what it was originally.