COLD ' STORAGE AND PRESERVATION OF FRUIT.

New Zealand Herald, Volume XXXII, Issue 9927, 17 September 1895, Page 3

COLD ' STORAGE AND PRESERVATION OF FRUIT.

[BY NORMAN SELFK, M.l.ttK,, M.LM.E., ETC.] (Continued?.) Whatever may be the caso with storage for short periods, it certainly cannot be taken as absolutley proved, in spite of some successful shipments from Hobarb, that ventilation with cooled air and open packages is preferable to close and airtight cases or barrels for lengthened storage and sea voyages. State Treasurer William H. Burnite recently made an efforb to treat the United States Ambassador, Thomas F. Bayard, to a taste of Delaware peaches in his English home, but the experiment was only partially successful, and the failure was attributed to the effect of ventilation with the sea air. Where it is absolutely necessary that a chamber should be often opened, and so admit air much warmer than the fruit at the upper part of the door while cold air escapes below every time the door is opened, it is possible that an arrangement of metallic surfaces might be devised to act a« a trap for the moisture, and catch the greater portion of the dew deposited, and having pipes to carry the collected water 'to the outside; bub where the chamber can be kept pretty well closed, as in over-sea voyages, it) is evident that ib must require much more refrigerating power to cool ib when the enormous currents of cold air are drawn off by ventilators and dissipated in the atmosphere, so that a continual fresh supply has to be cooled down from the atmospheric temperature before ib is senb into the chamber than it does when the chamber and its contents are cooled by the natural circulation of air, such air alternately taking up the heat and then expending ib either in melting ice or in heating the metallic surfaces of the refrigerator. In the latter case the heab from the air is either given up to cold metallic surfaces or melts the ice as in ordinary refrigerators and refrigerator cars, where the moisture is deposited sometimes as snow, which can be melted off, and at other times as water, which is removed by traps. In this connection it may be noted that a great deal more ingenuity seems to have been expended in securing dry air where the icing process is used than has been the case with systems of direct artificial refrigeration, as there are numberless patents having for their object the trapping of the moisture from melting ice, and in the refrigerating cars now being built for the New South Wales Commissioners of Railways the cold air passes over an immense number of strained wires, which have the effect) of separating the water and drying the air before ib passes up through the contents of the cars.

Twenty-five or thirty years ago, when the late Mr. T. S. Morb and Mr, Augustus Maurice were initiating cold storage for the preservation of food, New South Wales was probably far ahead of the rest of the world in this work, but there was no paper printed like Ice and Refrigeration then, and, if accurate observations were made, the results were nob printed for the benefit of future experimenters. After a quarter of a century, therefore, we find most diverse opinions still held on matters which ought to have been finally settled years ago. Take, for instance, the effect of freezing on the fibre of fish and flesh. In numbers of trials the mosb delicate flavour and texture has been claimed for Btored food, and acknowledged after months and months of hard freezing ; the same thing has since been proved in hundreds of cases with fruit, and nearly every mail-boat passenger has enjoyed the luxury of frozen peas, but in other cases we know that freezing has failed egregiously to preserve either flavour or texture ; in fact, a certain school on that account now advocates chilling, and not freezing, as the only reliable method of securing success in a shipping business. Yet what, after ?11, would a hundred failures under freezing really prove as against one success? Simply that in tbe one success certain conditions had been secured which were not attained in the hundred _ failures, nothing more. Those conditions, instead of concerning the freezing alone, are probably of a threefold character, relating— First. The condition of the food before it is frozen, with the method and the time taken to freeze it.

Secondly. The temperature and humidity of the air in the chamber during storage, and Thirdly. The manner in which ib is thawed afterwards. When you hear people discussing tho poor condition of thawed food, and saying "freezing it spoilt it," it would be well to bear in mind what a common failing it is to attribute effects to the wrong causes. The author was once watching the racing of two opposition steamers, when he heard a boy say, "Jim, if ever 1 have steamers I shall have red funnels, they always gets in first"just as logical a deduction and just as true as some that have been drawn from failure* in the chilling of food. At the present time the greatest attention is being devoted to the scientific processes of thawing out after freezing, great things are already attained in the case of meat, and possibly with artificial cold produced at a low cost it will soon be possible to freeze the most delicate fruits for transport and thaw them oub again as a commercial success. It is certain that if you once freeze them hard you can then keep them for any length of time and ab a comparatively low cost, because the cost in such cases is more a matter of insulation than of refrigerating power. Admitting as a resulb of the foregoing remarks thab there is still a great deal to learn with regard to the details of successful fruit and other food storage, it is still certain thab its practical success under varying conditions has already been so greab as to warrant this .conference taking into consideration what ;in America has been called NEIGHBOURHOOD COLD STORAGE. In an address on this subject delivered before the Western New York Horticultural Society last June, Mr. C. H. Perkins stated that what he referred to was not to bo confounded with the central or city storage system, under which as many as fifty thousand bushels of Bartietb pears are held in one store ab one time for canning purposes. He referred to district, or, as he preferred it, neighbourhood storage, to be run on the same principle as creameries and butter factories, by a number of neighbours combining to do well under the cooperative system what was very indifferently performed by individuals. As far as the dairyman is concerned, details no longer trouble him, and uniformity of quality is insured for his products, the brand of a particular factory becoming known and having its permanent value. This writer thinks similar combination would be profitable to fruitgrowers, and shows how much cheaper the system he advocates will be in delivery and other I charges. He also gives particulars of a building for the storage of nursery stock as well as fruit. CoLD STORAGE FOR TREES. Indirectly connected with the cold storage of fruit and interesting to fruitgrowers is the cold storage of young trees held over in order to prevent premature and irregular growth during the period in which there is a danger of the growth being started and then interrupted through a transient spell of warm weather. This is prevented by cold storage during the period within which the trees would be exposed to immature growth. Nursery stock has been thus kept for three years. / Professor Craig, of the Ontario Experimental Farm at Ottawa, is reported in a local paper of a few months back to havo stated thab a complete revolution in the apple trade would shortly be seen, and thab before two years there would be cold storage houses on the co-operative plan in every fruitgrowing district, After referring to the cold storage of fruit in the hot season at the World's Fair, kept from the previous summer, he spoke of beautiful California!! pears which ho had recently seen ab Montreal in Canada.

Just as tho neighbourhood cold storage or co-operative packing-house is the feeder for the central city store or the ocean steamer, so the farm cold store or cellar may be looked upon as a tributary to the " neighbourhood" one. Mr. Cobb, of New South Wales, has supplied (as before remarked) a good deal of information aboub the construction of cellars for fruit, and writing in a recent American journal, a Mr. S. W. Chambers advocates the erection of a cold storage house with the planting of every orchard, and suggests a very simple structure excavated out of a hillside. Nothing is said by him as to the actual temperature thab can be maintained in such

' a cellar, and it is impossible to form com*. parisons, but it appears to the author that the average temperature in most of the American States must be much lower than in Australia, and therefore simple devices which would answer there might nob be so effective here. This writer, however, is enthusiastic as to the advantages of such a house, the saving in fruit, and the increased prices realised. No doubt great benefits would accrue to fruitgrowers in this part of the world if they could establish similar fruit cellars or stores without a heavy expenditure. Although hundreds of thousands ot tons of natural ice are used for storage purposes in America, ib must be remembered thab an immense quantity of artificial ice is also used there for the same purpose; ice being retailed there in small quantities at prices as low as a farthing a pound, and in large quantities selling as low as 6s a ton. Ib would be absurd, of course, to pretend thab any -fruitgrower could accomplish similar results here by attempting to store fruit with ice purchased from the refrigerating companies ab from £2 to £3 a ton. The American fruitgrower's advantages over us in this respect seem at first to be very greab and many, bub there is really nothing to prevent artificial ice being made in these colonies by combinations of fruitgrowers just as cheaply as in America. From a paper read before the Pomological Society of Connecticut in January, 1893, by Mr. A. R. Moore, we learn that a house with 5000 cubic feet of storage capacity for fruit coat with the ice only 1155d01., say £230, and that the experience gained in ib was very varied, but ib was found oub for certain what has been discovered elsewhere, namely, you cannot pub in a poor article and take out a good one, although you might reverse that order, and that you must nob only select the best fruit, bub must take the greatest care of ib afterwards. Mr. Fowler, of the New York exhibit at Chicago, endorses this when he Bays:— ** No system of cold storage will make good fruit out of poor fruit, or protect fruit that is handled like cobblestones." Mr. Moore found that his house paid, and thought that four or five intelligent fruitgrowers might combine to build a cold storage house to hold from 800 to 1000 barrels if proper precautions and stringent rules were framed to prevent the friction which even among people of the best intentions might arise from carelessness in such matters as leaving doors open. EXTENSION OF THE SEASON FOR SPECIAL FRUITS. Altogether apart from export it is certain that we want some improvement in the, fruih supply to our Australian cities, in ; which branch of the business the local public is more interested. Look ab strawberries, for instance, how rare and expensive they are, ab least they are in Sydney, and how short their season is. "All strawberries are good," as the Kentucky man said of whisky, " bub some are better than others" (perhaps those grown ab great distances from town) and those are the fruits the city consumers want to get. An ancient worthy is credited with saying, " No doubt God could have made a better berry, but God never did, for it is food, drink, medicine, nectar, and perfume all in one." As the northern markets for strawberries in America have been extended by means of cold storage from April to August, there should be some scope for the extension of the strawberry trade in Australia. The same application may be made to many other kinds of table fruit.

Before leaving the subject of cold cellars on the orchard ib is worth while to consider whether more advantages may not be taken of our climatic conditions than we have yet availed ourselves of. First, as to the advantages of a great depth of earth to preserve equal temperature. The records of the Sydney Observatory show that the mean monthly difference of the average daily readings between maximum and minimum temperatures above ground is about 15deg. Fahrenheit, and the mean annual difference of such daily readings 33deg. But tho thermometers buried in the earth only show Instead of 15deg. range for tho monthly difference -. At 2tt Gin, s'3deg. ; at sft, 2'o9deg; ,at 10ft, l '7deg. Instead of 33deg. range for the annual difference: At 2ft 6in, 18"3 dog; at sft, 13"4deg. ; at 10ft, 9*2deg. ; at 19ft, 4 - 9deg. Clearly demonstrating the great advantages of depth and thickness of earth-covering for tho roof and sides of a cellar or store above ground in keeping' out external heat. The range of 15deg. in the average daily reading suggests that much might possibly be done to take advantage of the minimum temperature by opening out the store at such timas and closing it before the temperature rose again. Bearing in mind, however, what was said about humidity in the early ptrt of this paper, the author makes the following suggestion to orchardists :—ln order bo keep moisture from the fruit ib mighb be worth while to try the effect of the inner air-tight galvanised iron store room, enclosed in the insulated cellar or house, bub having air spaces all round the top, bottom, and sides between these inner and outer walls, such air spacos having inlet valves at the bottom and a tall outlet, or ventilating chimney, or draught pipe above. It is quite conceivable that with such an arrangement advantage could be taken of a cold damp atmosphere to cool the whole house and its contents by circulating a rapid current of cold damp air through these air spaces, which being outside the inner iron house there would be no possibility of conveying any moisture to the fruit inside.

Before concluding the author would say that if the orchardists of Australia, like those of Tasmania, mean to export largely to England they must be up and moving. On Augusb 10 last a train of 13 cars with 7800 cases of Californian peaches, plums, and pears passed through Chicago en route to London. This fruit nad over 4000 miles of land carriage bo stand before being taken on board ship—a point; in which we seem to have the advantage, because railway travel would probably knock fruit aboub more than the sea. This consignment was expected to realise a gross return of nearly £5000. The refrigerating machines and cold stores in America are numbered by thousands. If fruib can be frozen hard and thawed again under improved processes without deterioration there is not tho slightest doubt in the author's mind thab apart, perhaps, from apples, which do riot) require artificial cold as a necessity, the cheapest and most effective system will be to freeze hard, and keep the stores free from all ventilation, when ib has to be transported for long distances. The charges for small parcels of fruib to the usors of cold storage in America are only the sixth of & penny per pound, and probably the cosb is nob over half of that to the storage people themselves. No mention has been made of any particular firms, systems, or "makes of refrigerating machinery, although the author has designed plants undor all the leading types of machines now in use, using ether, cold air, and ammonia, etc., and has seen greab numbers of them at work ; he is, however, not interested as a manufacturer in one of them. It is worth while to point ouib here, however, thab under any system of artificial refrigeration there will be great advantages in a combination of fruitgrowers having one large cold store, instead of each individual acting for himself, on account of the relative high cost of small-powered refrigerating plants as oompared with larger ones. For instance, if a plant to refrigerate half a ton a day cost, say, £200 fitted up complete, double thab money, or, say, £400, would probably provide nob merely for a one-ton, bub for a two-ton plant—thab is of four times the capacity—and, say, £600 would provide a four-ton plant, or eight times the capacity for three times the cosb of bhe smallest size, and so on Hip to medium maohines of 20 or 30 tons capacity. Besides bhis the working expense of small machines is relatively much larger than with powerful plants. In making arrangements for purchasing refrigerating plant it musb nob be forgotten by the buyer that ib is nob only books thab are hawked ab the present 'day, a greab deal of machinery as well is now sold by plausible canvassers or agenbs, who can promise anything and everything to customers with whom they only expect to have the one transaction. Ib should be remembered also that there are makers' of first-class refrigerating machinery in these colonies that can be 'depended* on withoub going to America, Germany, and England for it. The best machines now working in New South Wales are probably two which were made in Sydney some years ago for the largest company there, and good machines are being made in more than one Australian city. An Australian purchaser who deals with an Australian manufactoring firm can always look to that

manufacturer to carry out his contract or redeem his promises, bub when money is sent abroad there is often no hope of redress for failures. A very large experience of the disappointments which have resulted in New South ales from placing orders for machinery with the agents of foreign firms leads the author to close his paper with these warnings to any who may be about to embark in artificial refrigeration. In such cases they cannot be too careful, and if they require professional advice or assistance let them be sure to discriminate between independent or disinterested experts and those 8«-called experts who are simply agents for the sale of certain manufacturers' goods. The refrigerating industry in these colonies is now extending by leaps and bounds, and if the fruitgrowers are going to take advantage of it it will be well for them to profit by all the past experience that is avail able. '