Food shelf life is mainly related to the dynamic of mass transfer in the food / packaging system. For instance, microbial safety of fresh products in Modified Atmosphere Packaging (MAP) implies to take into account the dynamic of O2 and CO2 exchanges in the system and its effect on microbial growth. Fresh fruits and vegetable decay is related to respiration rate that could be minimized using packaging material with the suitable permeation properties. We developed mathematical models of gas transfer (permeation through packaging and solubilisation/diffusion within food) coupled with models of food shelf life such as predictive microbiology or respiration. These mechanistic models, once validated, and connected to dedicated food and packaging databases, could be used as a Decision Support Tool (DST) in order to optimize the storage conditions of the product or to identify the packaging material the most suitable for the product.