Use of irradiation in combination with other treatments to improve the quality of precooked meals

Two different studies on the improvement in quality of precooked meals are presented. The microbiological, nutritional and organoleptic qualities of air packed, electron beam irradiated salmon pats were examined during a 42 day storage period at refrigeration temperature. The vitamin contents, although diminished, especially for retinol and alpha-tocopherol, were still appreciable. No lipid oxidation was detected. Under French legislation, the shelf-life of fresh precooked dishes should not exceed 6 days. In contrast, salmon pats irradiated at 2.5 and 6 kGy had a shelf-life of 11 and 23 days, respectively, at 4 degrees C. Electron beam irradiated precooked meals destined for immunosuppressed patients were also studied. The effects of low temperature (-40 degrees C) electron beam irradiation at doses ranging between 12 and 40 kGy, combined with vacuum packaging, on the bacteriological (sterility), nutritional (lipid oxidation, vitamin losses) and organoleptic qualities of selected precooked meals were investigated. All the meals remained sterile, even after 11 months of storage at 4 degrees C. Strict hygienic conditions were maintained during their preparation. The irradiated meals, which consisted of duck with orange sauce, chicken, salmon and white fish, fried potatoes, stuffed pancakes, rice with currants, and mashed potatoes and carrots, all showed good organoleptic qualities. Off-odour and off-flavour were detected only in the irradiated fried potatoes, which were rejected because of their soft texture. It is suggested that those meals that are organoleptically better than autoclaved foods could be proposed for immunosuppressed patients.