One of the main post-harvest problems is the emergence of spoilage in oranges caused especially by fungi that depreciate the quality and decrease shelf life and may also compromise food safety. Various treatment technologies such as: modified atmosphere, irradiation, anti-microbial ice and high pressure, among others, have been studied in the quest to eliminate food pathogens. Thus, understanding mechanisms of microorganism control in foods have been the topic of intense research with the use of various techniques and physical, chemical and biological processes. This project proposes the development of respective methods and instrumentation techniques to decrease and monitor the spoilage microorganism development processes in fruits based on incident ionizing radiation, in controlled doses regarding time exposure, intensity and pulse frequency (modulation).