THAWING FROZEN MEAT.

Dominion, Volume 5, Issue 1399, 27 March 1912, Page 8

THAWING FROZEN MEAT.

RAPID THAWING DETRIMENTAL. It is certain that ton rapid thawing of frozen meat has «. bad effect on its quulitv. This has keen recognsod for veavs "past bv those having a practical knowledge of the business. Jt has, however, been difficult to convince consumers that careless handling of frozen meat after it is taken from the cold chambers has frequently been responsible for its inferior finality. Dr. Richardson, chief chemist for Messrs. Swift and Co., in giving evidence l>efore a select committee of the United States Senate, gavo some interesting particulars concerning tho effect of freezing and thawing of meat at a vapid rate. Ho said: "We desired to know the exact, condition of muscle, muscular tissue, in a frozen condition, believing that such information would give us important data on the subject. Muscular tissue consists of elongated cells, which are called the muscle hbres; they have a slight diameter, about one five-hundredth of an inch, and their length is considerable, from threequarters of an inch to an inch and n half. These fibres contain the various elements and substances which perform tho functions of the muscles. They have, of course,•« typical miscroscopic structure but what interests us more particularly is their chemical nature. When such a tissue is placed in a freezer the water which is contained within the hbres does not freeze within the fibres, but freezes outside the fibres, and tho first water that freezes out freezes in a pure condition. In other words, it forms a thin layer of ice around each individual fibre or group of fibres. As the freezing progresses naturally the fibres are contracted, are forced" together into small bulk by the freezing process. In the final frozen condition, tliey have a wide uncontrolled field for if the muscular tissue is examined under the microscope,, it presents a very., different appearance from the original muscular tissue. Instead of finding the fibres adjacent to one another or, separated only by a little connective tissue, we find them entirely isolated either individually or by groups by 'regions of ice. In other words, the organic substance has been forced into a contracted form, and remains in tho meat isolated by solid walls of ice, "In one aspect of the drying, therefore, the freezing process is a drying process, it is a dessicating process, because the substances within the fibre in a frozen condition contain very little water. The fibres arc in a dry condition, and these fibres arc surrounded by the water frozen solid as ice. When muscular action is thawed the reverse action takes place. The iee as •it thaws is reabsorbed into the muscular tissue, so that, ultimately, if the thawing is carried out moderately slowly, the fissile assumes its original condition and the original appearance provided the thawing is done slowly. When the thawing is ranid the cells themselves do not come quite back to their original position. They have been distorted by the frozen process, and they do not quite come back into contact again. There may bo little space left between them which were occupied by the ice in the frozen condition. Some of the fluid would drip out of the meat, but with slow thawing that docs' not occur. The ice which has come out of the cells lies adjacent to tho cells, and so far as could be ascertained the same water would go back into the same cells. You would have to split hairs to say anything different from that. •

"We have investigated the possibility of the penetration of bacteria into meat, or their growth and development in the meat in the frozen condition, and have made various studies of frozen tissues with a view to ascertaining how good a medium such frozen tissues would-be for the development of bacterin. We found that when fatty materials were put into the freezer all the ordinary' changes which occur in tho storage ot fats ceased, or, if they continued, it was not possible by any chemical means to detect these changes. In other words, they were so slight as to be negligible. The"minimum age of beef which we have examined was two days, and our principal experiments continued up .to two years. •We have, however, in other cases and in a fewer number of experiments, continued the work up to three years, and in still fewer cases up to six years. The gross appearance of frozen meat is never different from the gross appearance of the fresh meat. Tho exterior surface has the same appearance,.it has the same texture and colour. The beef was just as wholesome and just as palatable at the end of the longest period as it was originally. We have not reached the limit of the possibility of freezing in storage. There is absolutely no known limit if properly kept in cold storage. All our experiments were carried out at lodes?, or lower. The highest temperature we used in freezing meat is ladeg. The conditions which favour the

oxidation of tho fat by the air arc heat and light, particularly sunlight. In the freezer we have the opposite of these conditions, we have low temperatures, and tho absence of sunlight, being lighted by artificial light, which is ineffective."