The reliance of minimally processed chilled foods on low temperature for distribution with optimized controlled/modified atmospheric packaging to maintain safety and quality poses new challenges to food microbiologists. Effects of controlled/modified atmospheric packaging conditions on microbial growth are briefly discussed. Microbial growth models are systematically examined with emphasis on the temperature dependence models - the Arrhenius model and the square root model. Their applicability for making predictions of both shelf life and safety under nonisothermal conditions is assessed. The use of time-temperature integrators for shelf-life prediction and safety assurance is also addressed.