Treatment of meats with ionising radiations. VII.—effect of low temperatures during irradiation

Abstract

Abstract Raw pork and beef have been irradiated with 2 MeV electrons at controlled temperatures from + 18° to −296°. Appearance, odour and flavour were assessed by a taste panel, the destruction of glutathione was estimated chemically; and the extent of the survival of the bacteria determined. In each case, a relation to the temperature of irradiation was observed similar to that previously recorded for thiamine. There was little effect between 18° and 0°; but a rapidly increasing protection from 0° to −20°, with a smaller increase down to −196°. Experiments in the range 0° to −10°, in which destruction of glutathione was the criterion, indicated that protection began when ice separated from the tissue. It is suggested, accordingly, that the degree of protection depends on the amount of free water withdraw from the system. The importance of precisely defining temperature during irradiation is emphasised. It is concluded tha freezing will be of little benefit in radiation pasteurisation processes aimed at destruction of vegetative micro‐organisms; but that it might be helpful in radiation sterlising processes, as the protection is smaller for spores.