Refrigeration and the Export of Meat [51] (continued)

By the end of the century, two major defects of frozen meat had begun to tell against the Australian product. The first was 'drip' and the second 'freezer burn'. Drip was the release from the thawing meat of a watery blood-stained liquid. It was due to the rupture of some of the cell structures of the meat by slow growth of ice crystals in them, so that on thawing the liquid normally held within the cells dripped away from the carcase. It was not dangerous but it was unsightly and was not observed in the chilled meat which, because of the shorter distances, was being shipped successfully to Britain from South America. Freezer burn is equally harmless but equally unsightly. It is due to the intense dehydration of the surface of meat which is exposed to the extremely dry air of the refrigeration chamber. Tissue so affected is unacceptable. Adequate protection of the surface of the meat is the answer to freezer burn, but drip was another matter and for a long time inhibited Australian exports of refrigerated meat. Drip had been observed in 1873 by Dr. J. I. Bleasdale during his examination of Harrison's product.[58] It did not appear in chilled meat held just below WC, but at those temperatures microbial spoilage occurred during the voyage from Australia to England. This did not happen during the shorter voyages from Argentina, and South America chilled meat thus enjoyed a significant advantage on the English market.

Early in this century several attempts were made to get chilled meat through. In 1909-11, a lot of beef was shipped from Queensland using the Linley process which was of South American origin and in which meat was held at - 1 to - 1. 5'C and exposed to formaldehyde vapour for 1 hour per day. It was discontinued when the British government ruled against formaldehyde. Then L. F. Bullot, a New Zealander living in Sydney, obtained patents both here and overseas for a process for preserving meat by exposing it to the combustion products of a complex mixture including sulphur, nitrate, wattle bark, and some essential oils. Bullot's claim that his process facilitated the shipment to Britain of subsequently chilled meat seemed valid inasmuch as the defrosted meat remained sound longer than the untreated controls. Drip was, however, still present, the superficial appearance was altered and there was official British objection to the preservatives. In the 1920s the process was investigated by CSIR, which could not recommend its general adoption. A third empirical solution suggested was that of an Australian engineer named Perfect. He obtained a patent for it but it was essentially the circulation of ostensibly humidity-controlled air through the meat. The process was partly successful but losses by desiccation doomed it.[59]

Australian Academy of Technological Sciences and Engineering