Numerical simulation was carried out to predict the effect of external temperature conditions on thermal behavior of frozen US military rations, during storage and transportation. An army breakfast menu box containing beefsteaks, Based on this adjustment thermo-physical properties were evaluated and used in numerical simulation of freezing process. The average deviation in numerical temperature prediction from the experimental data was 2 °C, during freezing. A generic numerical simulation technique was developed which can be used to predict heat transfer in any food system experiencing phase change, under varied external temperature conditions. Specifically, it can be used for frozen foods that are more susceptible to temperature abuse during very long duration of transportation. For these food items, estimating the extent of spoilage from the time-temperature history alone is difficult. Hence, temperature history obtained from this model can be combined with the microbial or chemical kinetics, to predict the food safety and quality as a function of external temperature conditions. This work was extended to predict the microbial safety of the food items in the army menu box during real-time temperature abuse scenarios, which is presented in detail in a separate manuscript (Part 2).