Provided are systems and methods for treating or processing tissue, and tissue products made using such systems and methods. The methods involve combining tissue with a processing solution in a processing vessel and applying resonant acoustic energy thereto. In some instances, the tissue is processed in the absence of processing solution. The resonant acoustic energy rapidly agitates the tissue with the processing solution by vibration. The general method provided is broadly applicable to a variety of tissue processing methods, the processing solution and features of the resonant acoustic energy being selected based on the type of tissue to be processed and the nature of the processing to be performed. Exemplary methods include methods of bone demineralization, tissue decellularization, tissue cryopreservation, production of stromal vascular fraction, tissue homogenization, tissue cleansing, and tissue decontamination, and assessment of microbial load. By applying resonant acoustic energy to the tissue during processing, the rate or efficiency of processing, or both, may be improved.