The article describes the problem of stress analysis in spray sterilizers according to EN 13445-3, widely used in the food industry. Operating conditions of the test device were characterized and a method of design verification using FEM was defined. Conditions of computer implementation research were determined and choice of a methods for assessing sterilizer was made, based on stress analysis. It was found a criterial stress for material of which the vessel is made. The maps of characteristic stress was generated, the areas of concentration was localized and confronted the results of set limits. Moreover, the fatigue life of welds and base material were estimated. As a result, an effort of the state system was determined. It was found that the structure is characterized by level of safety, which allows to build a prototype for validation of numerical model by strain gauge methods.