[en] Experimental batches of a stuffed pasta product, 'Tortellini' and slightly pre-fried breaded reconstituted turkey meat steaks with cheese and ham filling, 'Cordon Bleu', were prepared according to commercial recipes then inoculated to 10⁴ CFU/g with Staphylococcus aureus (in case of Tortellini) and to 10⁶ CFU/g with Listeria monocytogenes (in case of Cordon Bleu) prior tp packaging in plastic pouches under a gas atmosphere of 20% CO₂ and 80% N₂. The inoculated packages were irradiated at 3 kGy (Tortellini) and 2 kGy (Cordon Bleu) by a ⁶⁰Co radiation source. The applied radiation doses were sensorically acceptable with these products. The experimental batches of Tortellini were stored at 15 deg. C, while the Cordon Bleu samples were stored at 5 and 9 deg. C respectively. Unirradiated samples were kept together with the respective irradiated ones. Storage was continued for four weeks and microbiological testings were performed before and after irradiation, and subsequently after every seven days. Besides selective estimation of the counts of the test organisms, total aerobic counts, and in case of Cordon Bleu, also colony counts of lactic acid bacteria, Enterobacteriaceae, sulphite reducing clostridia, yeasts and moulds were also selectively estimated. The 3 kGy dose reduced the Staph. aureus count in Tortellini below the detection limit (log_1CFU/g = 0.26), and it remained undetectably low in the irradiated samples during the whole 28 days of storage, while the Staph. aureus count in the unirradiated samples increased up to 10⁸ CFU/g for the 8th day. The Listeria count in cordon Bleu was reduced by irradiation from the initial log CFU/g = 6.1 to log CFU/g = 3.5. At 5 deg. C storage, this residual count remained stagnant up to 3-4 weeks, but started to increase at 9 deg. C after one week. In the unirradiated samples, the Listeria count increased hundred-fold during 4 weeks at 5 deg. C, and during 2 weeks at 9 deg. C. Sulphite reducing clostridia were and remained undetectable (log CFU/g < 0.48) in all samples even at 9 deg. C. The limiting factor of the shelf-life of the unirradiated poultry product was the growth of lactic acid bacteria at 9 deg. C, whereas enhanced lipid oxidation was an unwanted side-effect of radiation treatment. One can conclude from these studies that the potential risk posed by the investigated non-sporeforming pathogenic bacteria could be considerably reduced by gamma irradiation, however, storage temperature remains a crucial factor of safety and methods should be developed to counteract the lipid-oxidative effect of the radiation processing. Pasteurising effect of 2 kGy radiation dose in nonfrozen mechanically de-boned turkey meat (MDM) was achieved without increase of cholesterol oxidation products (COPs) and increases of TBARs values (thiobarbituric acid-reactive substances)during 15 days of chilled storage following the treatments, while untreated samples were spoiled. Addition of antioxidants, such as thyme-oil or α-tocopherol inhibited significantly the oxidative changes of cholesterol and lipids during 3 kGy treatment. As a result of intensive predictive microbiological modelling activities, several computer programmes and soft wares became available recently for facilitating microbiological risk assessment. Among these tools, the establishment of the ComBase, an international database and its predictive modelling soft wares of the Pathogen Modelling Program (PMP) set up by the USDA Eastern Regional Research Center, Wyndmore, PA, and the Food Micromodel/Growth Predictor by the UK MAFF Food Research Institute, Norwich, are most important. We have used the PMP 6.0 software version of ComBase as a preliminary trial to compare observed growth of selected test organisms in relation to our food irradiation work during the recent years within the FAO/IAEA Coordinated Food Irradiation Research Projects D61023 and D62007 with their predicted growth on the basis of growth models available in ComBase for the same species as those of our test organisms. Results of challenge tests with Listeria monocytogenes inoc ulum in untreated or irradiated experimental batches of a semi-prepared breaded turkey meat steaks ('Cordon Bleu'), sliced tomatoes, sliced watermelon, sliced cantaloupe, and sous-vide processed mixed vegetables, as well as Staphylococcus aureus inoculum of a pasta product, Tortellini, were compared with their respective growth models under relevant environmental conditions. This comparison showed good fits in case of unirradiated and high moisture food samples, whereas growth of radiation survivors lagged behind the predicted values. (author)