FROZEN PRODUCE LETTER

Press, Volume LXXIV, Issue 22593, 24 December 1938, Page 15

FROZEN PRODUCE LETTER

BLOOM ON CHILLED BEEF HANDLING REFRIGERATED FOODSTUFFS (From Our Special Correspondent.) LONDON, December 1. The. loss of bloom, or deterioration of the surface tissues, has long constituted a leading technical difficulty in the export of chilled beef from New Zealand and Australia. The loss of bloom may be apparent through the fatty tissues becoming bleached and discoloured. Recently, to provide scientific data that might be turned to practical account, arrangements were made for an experimental shipment of chilled beef to be carried in the Sussex from Australia to London.

Df. Gane, of the Low Temperature Research Station, Cambridge, and Mr N. W. Holmes, of the Food Preservation and Transport Section of the Australian Commonwealth Council for Scientific and Industrial Research, accompanied the shipment, and made careful observations of temperatures and humidities in the storage chamber during the voyage. The trade is now anxiously awaiting the report of these two research workers who are understood to have arrived at a practical formula to eradicate much of the loss of bloom that occurs at present.

It was already known that the extent of the loss during storage was mainly dependent upon such factors as the pre-slaughter treatment of the cattle, the treatment of the carcases and sides on the slaughter floor and during chilling, the initial colour and quality of the meat, the temperature conditions, the composition and drying power of the storage atmosphere, the duration of storage, and the pattern and degree of tightness of the stowage on shipboard. Even with the use of 10 per cent. CO2 there has been considerable dispute, particularly in the trade, as to whether it directly causes an increased rate of loss of bloom. In fact, many importers in Great Britain have blamed the use of this gas for the frequent appearance on certain fatty tissues of a marked greyish discoloration, but experimental evidence indicates that, all other things being equal, there is no perceptible difference in the rate of loss of bloom of comparable chilled beef stored in air and in 10 per cent, carbon dioxide, at least up to 50 days’ storage. . . , With regard to the drying powef- of the air, which is dependent on its relative humidity and the rate of flow, the experimental evidence so far available strongly suggests that, within limits, the greater the rate of loss of moisture from the beef, the lower the rate of loss of bloom. However, the drying rate should not exceed 2i per cent, loss of weight in 45 days if loss of bloom through excessive desiccation is to be avoided. Chilled Beef Storage The Food Investigation Board has reported that, owing to the numerous factors influencing the rate of loss of bloom, there is no simple relationship between the duration of a storage and the extent of the loss of bloom. Under certain conditions, serious loss of bloom may occur after 45 days’ storage, while a similar loss may not occur in another lot of beef until 60 days have elapsed. All factors being equal, however, the extent of the loss is dependent upon the duration of storage. Given careful attention through each stage of treatment from slaughter onward, no appreciable loss of bloom occurs up to six weeks. After that time the risks increase markedly, and after 60 days the odds against the beef arriving without serious loss of bloom are high. The method of stowage on shipboard has a marked influence on the appearance of the beef on the English markets and deterioration caused by faulty stowage may be of two types —(a) discoloration and mechanical injury due to chafing, and (b) marked discoloration of fatty areas on contact areas between adjacent quarters. The first type of defect may arise through irregularity or unsuitability of the stowage pattern, or by slack stowage, each leading to the rubbing of one quarter against another when the vessel is rolling and pitching. The second type of defect may arise through irregularity, or bad design of the pattern, or too tight stowage. Careful attention must, therefore, be given to stowage by stevedores, and the Food Investigation Board recommends ships’ officers to secure regularity of pattern and to avoid either too tight or too loose a packing of the quarters. , . , , .... ~ Since the most desirable “tightness” of packing in cubic feet a ton of beef depends upon the mean weights of the quarters, the height of the cargo space, the ratio of hindquarters to crops m the shipment, and the extent of the structural obstructions to uniformity, it is impossible to state any precise figure to be adopted as a standard. In one cargo space, a stowage rate of 112 cubic feet a ton may be adequate, whereas in an adjacent space, with different beef, it might result in far too tight a stowage. A.s the board, points out, the stowage of chilled beef is really an art. success in which can only be acquired by long experience. The trend of recent research into the handling of refrigerated produce formed the basis of an address by Dr. R. G. Tomkins at a sessional meeting at Cambridge of the Royal Sanitary Institute. Dr, Tomkins said that the factors which are largely responsible for modern trends in food preservation include the improvements made inrefrigeration machinery and the introduction of dry ice, large : scale planting of fruit trees in countries overseas, and the problem of using culls, research into food preservation problems, and the prohibition of the use of preservatives in accordance with the Public Health Regulations. . ..... , Recent improvements m the_ chilled meat industry have been attained by attention to ante-mortem factors, hygiene in preparation and handling, and the introduction of gas storage. Improvements in the frozen food industry have been effected by better methods of freezing, storage at lower temperatures, and delivery to the consumer in the frozen condition. Fruit Storage According to Dr. Tomkins, advances in the storage and handling of fruit have been due to improvements in orchard and handling practices, investigation into the best temperature of storage and the methods of cooling fruit, the discovery of gas storage and the use of ethylene for cooling fruit. Fruit juices are being sold in increasing quantities and recent research, applied commercially, has opened up

the consideration of bigger shipments from certain Empire countries and a possible new market for others more distant from the United Kingdom. The bulk of the fruit juices are preserved by the use of sulphur dioxide or benzoic acid, but increasing quantities are now being preserved by pasteurisation. ultrafiltration, carbon dioxide under pressure, and by concentration by freezing. Another interesting development is the clarification of juices by the use of enzyme preparations. The frozen pack method of preserving fruits and vegetables for dessert and culinary purposes is being rapidly developed. The quality of these products is determined by treatment before freezing, the method and rate of freezing and the temperature of storage. Advances in the canning industry have been due to more exact knowledge of the time and temperatures needed to secure sterilisation, improvements in the methods of making and sealing cans, and improvements in the types of steel and lacquers used in making the cans. There have been advances in the preservation of many prepared foods and in the knowledge of pectin jellies which determine the settling of jams. Serious losses are still often exper. enced in the handling of fresh foods, and some of the possible methods of reducing these losses, which are being investigated, include methods of sterilisation which do not produce changes in the products, the treatment of fruit with disinfecting solutions or gases, the use of wraps impregnated with slightly volatile fungicidal compounds, and greater certainty in predicting storage life.

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