Combined Irradiation-Heat Processing of Canned Foods

The quantity of ionizing radiations needed to sterilize canned foods generally impairs both their nutritive qualities and palatability (Hannan, 1955; Schultz et al., 1956). However, thermal processes also lower these qualities in canned foods (Stumbo, 1949). In both instances, the extent of damage increases with the severity of the treatments. Consequently, the heat processing schedules that are used industrially are based upon the minimum levels required to kill those microorganisms that might endanger the health of consumers or which would cause the food to spoil during storage (Stumbo, 1949). For these reasons, new sterilizing techniques that will retain or improve the organoleptic properties of canned foods without lowering their safety or nutritional qualities are constantly being sought. Since it has recently been shown that heat and gamma radiation are synergistic when used together for killing the spores of anaerobic bacteria (Morgan and Reed, 1954; Kempe, 1955), it is possible that combined irradiation-heat processing of canned foods could result in an improved procedure. The present study is concerned with establishing combined irradiation-heat processing schedules for previously heat sterilized ground beef that was then inoculated with Clostridium botulinum 213B spores before the cans were closed. Future studies will deal with experiments utilizing putrefactive anaerobe (PA)3679 spores.