A system for producing secondary food product from primary food product waste is disclosed that comprises several modular subsections: a staging subsystem, a processing subsystem, a drying subsystem, and a pelletization subsystem. Each subsystem, and the connections between subsystems, are sealed such that the food product being processed is isolated from the general environment. Product is dried by the dryer in such a way that it emerges from the dryer at a desired moisture content level and at ambient temperature. A moisture sensor may provide control data to a controller that in turn controls product throughput to obtain a desired moisture content level. High nutritional content and long lifespan of the processed product can be maintained, while reducing the weight of the final product. One or more of the subsystems may be portable and configured for convenient connection and disconnection to mating subsystems, and to facilitate permitting for portable operation.