Colorectal cancer is the first cause of death in non-smokers: each day one hundred new cases are detected in France and 45 of them will die within few years. Red meat and processed meat intake is clearly a risk factor for colorectal cancer, according to meta-analyses of epidemiological studies. The increase in risk is not very high (+25-30%) but WCRF-2007 panel recommendations are strong: "Limit red meat intake (300 g/week at a population level), and avoid processed meat intake". These key recommendations to improve public health could lead to a drastic reduction of meat intake, and could have dramatic economical consequences be dramatic on the processed meat pork industry and on the bovine market. The research of preventive strategies is thus important to reduce colorectal cancer risk without eliminating any food from our plates. Two strategies can be considered: (i) industrial processes could be modified to produce healthier meat and processed meat, and (ii) consumers could adhere to specific recommendations (e.g., eating a specific protective food in the same meal as processed meat). The first suggestion would lead to production of processed meat without cancer risk, by changing food processing: the goal of this project is thus to define processing, and packaging that would improve food safety and decrease colorectal cancer risk. The central hypothesis is that heme iron in meat would increase lipoperoxidation, nitrosation and cytotoxicity of the intestinal content. Resulting aldehydes and N-nitrosated compounds would select tumor cells and promote tumor growth. The present project will thus test additives and processes to make beef and pork meat products that limit fat peroxidation, N-nitrosation, and cytotoxicity in the colon lumen. Most effective modifications will be identified in animal and cellular models, and these modifications will be validated in human volunteers. In addition, the research of molecular mechanisms should lead to new molecular biomarkers that we will use to translate results from rodents to Humans. Furthermore, the project aims to validate the acceptance of these new meat products by consumers, testing their sensory (organoleptic) properties. The project is structured in six steps: (i) beef and pork meat processing to obtain 28 beef meat products and 16 pork meat products. These products will be given to rodents to test (ii) the impact on peroxidation, cytotoxicity, nitrosylation and iron status in the colon. Following this step, six meat processes will be chosen, according to their effect on the above cited biomarkers. These six processed meats will be tested in rodents to see (iii) their effect on colorectal carcinogenesis, and (iv) their cellular and molecular mechanisms of effect. (v) Relevance of these processes will be tested in “real life” industrial workshop. Eventually, three processes will be chosen to be tested in human volunteers (vi) to check their effect on fecal peroxidation and cytotoxicity and on consumer acceptance. This scientific project is thus part of the effort of food industry to improve continuously the safety of food products, and specifically to adapt to the recently identified cancer risk associated with meat consumption.