TRANSPORTING PRODUCE

New Zealand Herald, Volume LXVIII, Issue 20867, 8 May 1931, Page 17

TRANSPORTING PRODUCE

FRUIT AND MEAT. COLD STORAGE PROBLEMS. NEW FREEZING PROCESS.

BT WALTER BITTEN.

With the aid of funds from the Empire Marketing Board tho transport problems of overseas Empire producers who supply fruit and moat to Great Britain are being investigated by workers at the Low Temperature Research Station, Cambridge. Ideal facilities for the investigation of wastage in imported fruit have been creatod by tho erection of tho Ditton Laboratory at East Mailing, Kent, which is tlio largest experimental cold storage institution in the world: The main featura of tho laboratory is tho groat central chamber, built in the form of a ship's hold (one-fifth ordinary hold size) and capable of containing 120 tons of apples. This will be used for tho study of fruit storage and transport and of refrigeration on a .commercial scale. As a means of reproducing the wide range of temperatures through which a fruit cargo may pass during a long voyage tho chamber is surrounded by a 3ft. wide envelope of air, which can be heated and cooled at will.

Storage of Meat. The storage of fruit for long transport is, of course, an entirely different matter from that of meat. As fruit 13 alive anil breathing—taking in oxygen and giving out carbon dioxide —it alters the composition of the hold's atmosphere. .Further, it gives out moisture, thus changing the humidity of the chamber, and it also exhales heat, which affects the temperature. Under the ideal conditions of transport storage which may be expected to be developed in tho future it will bo possible to regulate these three factors —atmospheric composition, humidity and temperature —and it is to this end that tho work at East Mailing is being directed. One specially important point which is being tackled is how to got an even temperature throughout the hold as the result of tho cooling process. sVhcn, as not infrequently happens, a cargo is cooled too strongly at the sides, wastage from freezing or from "internal breakdown follows, while at the same time heat produced at the centre is not removed sufficiently fast, thus causing overheating, wastage from fungal rotting and overripeness. The better distribution of cold air is a matter of first importance. How to bring it about quickly is being carefully studied. Though tho wastage in apples from New Zealand is relatively small it is expensive and the improvements in storage methods which may be expected to result from this largo scale work at East Mailing are bound to effect a considerable saving.

Freezing Methods Compared. In relation to meat, too, there are big problems in. low-temperature research which are now being effectively investigated. The great mutton export trade from New Zealand to Britain has been made possible by tho fact that mutton can be frozen practically without any depreciation of value. Frozen beef, however, has hitherto been much less satisfactory. This is becauso of the greater, size and thickness of a beef in consequenco of which hard freezing is a slower process than with mutton. In slow freezing tho water is drawn out of the tiny cells of the meat tissues, forming ice crystals in the intercellular spaces. Since water expands on freezing, these crystals forco apart the muscle fibres and disrupt the cells. When thawing occurs the deflated cells are unable to reabsorb their lost juices, which escape as "drip," a result which not only gives the meat an unattractive appearance,_ but also involves a loss of much nutritive material. On the other hand, when freezing is quick, the water has not time to ooze out of tho cells and it is frozen there in situ, with little rupture of muscular fibres, and no subsequent "drip" of juices. The ideal of instantaneous freezing is more nearly attained in tho smaller carcases of mutton which take much less time than beef to freeze through. Possibilities with Beef.

It will bo seen that a possibility in the freezing of beef is to reduce the size of the meat mass to bo frozen, thus putting beef more nearly on the terms of mutton. In such a system carcases would be cut up and the joints frozen separately. This method appears to bo in rapid process of development in the United States, where wo hear of carcases being divided, immediately _ after slaughter, into quite small cuts, install* taneously frozen ar.d distributed throughout the country in insulated waggons. A few consignments of "quick-frozen" meat have, in fact, reached the London market, and English butchers, foreseeing the possibilities that lie in this new method, are apprehensive that some of their trade may be appropriated by grocers, who have only to supply themselves with small-scale coldstorage plant for the purpose. Another possibility envisaged by workers in low-temporature research is to extend the period of chilling moat. Beef can now be kept satisfactorily for 25 days, or oven longer, at slightly bolow freezing point. Scientists belicvo that the period could bo extended to at least 40 or 45 days. In England the Food Investigation Board is studying particularly tho possibilities of preventing the growth of mould fungi which tend to appear on chilled moat by such methods as reducing humidity and adding to the air small traces of certain gases which chock mould growth. It seems, therefore, that in the not-distant future beef may bo shipped successfully from Australia and New Zealand to England in merely "chilled" condition, in which form it is much more acceptable to consumors I than the frozen article.