COLD STORAGE PROBLEMS

Sun (Auckland), Volume III, Issue 857, 28 December 1929, Page 25

COLD STORAGE PROBLEMS

Investigations Into Lamb And Mutton Trade

A party of three scientists left England a few weeks atro for New Zealand to undertake a cold storage survey of the New Zealand mutton and lamb trade with the United Kingdom. The of'’the traYe 6 f XPe< lv 10n , 1S to , obtain an exac 't scientific picture ot e rade from the slaughter-house in New Zealand to the clocks in this country. 1,0 Lue

lbe which should result from the survey, linked °nL a T d / r 0 1? fumlamenta! studies which are proceeding at the Cteinbridge Low Temperature Research Station, will, i‘L* h °P ed > adG a further chapter to the science of cold storage ot meat upon which future progress in its transport and utilisation so largely depends.

Dr Ezer Griffiths, I'.R.S., of the National Physical Laboratory, assisted by Dr Vickery and Mr Haddow, both of the Cambridge Low Temperature Research Station, comprise the survey Irani, which is to be strengthened, ori it. return journey, by the addition of New Zealand and Australian workers, states the London “Times.** These workers will join the expedition in its •tody of humidity and air movement in the holds, after which they will remain in England for some months to obtain an insight into the methods of tood investigation followed by the Department of Scientific and Industrial Research at Cambridge and elsewhere- The Empire Marketing Board and the New Zealand Meat Producers’ Board have both made grants to enable the expedition to take place. The cold storage survey represents a practical field of investigation into actual commercial conditions which will be of assistance in the general scheme of research being followed at Cambridge.. The work of the Low Temperature Research Station is directed towards fundamental research into the effect of cold upon fruit and upon meat, with the reduction of waste in transit and improvement of storage conditions for its ultimate aim.

The biological behaviour of frui*. under cold storage conditions is well understood in comparison with the behaviour of meat, which, on account of its extreme complexity, must be studied from a fundamental point of view before research into problems of technique can be profitably attempted- The structure of muscle, the changes it undergoes after death, the meaning of rigor mortis, the chemistry of fat, the effect of enzymes, bacteria, and moulds on fht rancidity, and the structure of connective tissue arc among the problems under consideration. Through a study of the structure of meat its behaviour under certain conditions may often be explained. A microscopical examination of the tissue, for instance, showed that the cause of “drip” lies in the mechanical effect of low temperature on the cells. Whereas mutton can be frozen for long periods, and subsequently thawed, cooked, and eaten without loss of quality, beef does not lend itself to freezing. When beef is thawed a “drip” escapes from the carcass, bearing with it some of the nutritive juices of the meat and leaving the Joint relatively dry and unappetising. The freezing of meat causes ice crystals to form in spaces between the cells of the tissue. Practically no change in structure takes place if freezing is almost instantaneous; but if the process is slow, muJ 1 of the cell moisture is drawn out of its compartments, and comparatively large fee crystals are formed In the intercellular spaces. These crystals push the meat cells apart and the tissue becomes broken up and stringy; further, on thawing the water

is not re-absorbed, but runs out as “drip.’’ Mutton, being in small portions, can be froien through much more quickly and so avoids loss of cell moisture; but beef, on account of the larger bulk of its joints, freezes through so slowly that “drip” results on thawing.

Another problem which awaits solution is the transport of chilled meat over long distances. At present, chilled beef from Australia and New Zealand cannot be landed in this country in the reliable condition essential for commerce owing to the growth of moulds and bacteria, which appear if the period of chilling is too much prolonged. The possibilities of checking their activities are being .explored from various angles by the* Cambridge workers. Experimental consignments of Australian chilled beef have actualy been landed in this country.

It is clear that work of this sort, if successful, ■would greatly extend the radius within which wc can obtain our meat, and would open up possibilities of drawing supplies from countries of the Empire which are still too far off to compete with foreign exporters. In the more direct aspects of the work Cambridge. scientists are undertaking specific investigations, such as the question of loss of “bloom” in New Zealand mutton. The important bearing of such work on. successful marketing has led the Empire Marketing Board to contribute a considerable capital and maintenance grant for the expansion of the Cambridge Station and the erection of new laboratories and cold storage plant. These are nearly completed, and will enable investigations into the storage of meat and fruit to to he undertaken on a much larger scale than before. At the same time, a model ship’s hold is in course of erection at East Mailing. In this it will be possible to repeat on a commercial scale some of the laboratory experiments on fruit carried out at Cambridge. Theories will be tested in a practical way, and “true-to-life” conditions reproduced. A great deal of work has already been done on the cold storage of fruit. An intensive study has been made, for example, of the ripening process. The right balcold storage is to delay ripening by reducing, the respiration of the fruit. The breathing of apples in ship’s holds Is responsible for various storage diseases, such as “brown heart,” which is caused by suffocation of the apple due to an excess of carbon dioxide; but a certain percentage of this ggs in the atmosphere acts as a preservative and checks the ripening process. The right balance of carbon dioxide is one of the problems to which much attention is being paid.

Questions of humidity and the possibilities of gas storage—the regulation of the composition of the atmosphere as well as of its temperature—are among the problems which are being studied, and upon which a more intensive campaign will be launched when the new laboratories* are ooened