Abstract. Fruit growers and handlers need better methods to determine the firmness and storage potential of fresh fruit. Fruit quality can be predicted by measuring mechanical properties during various simulated loads. Drop impact testing of a single fruit is a good compromise between an ideal, highly controlled and a realistic, but less controlled load. The force vs time curve during impact provides numerous parameters which have been related to peach firmness and have been used for many practical applications. The impact variables contact time, peak force, peak force/contact time, and absorbed energy varied with fruit ripeness and between cultivars. Peaches were firmer when picked in the cool morning compared to the hot afternoon. Impact parameters and firmness were measured for various cooling and storage air treatments. Ali indicators show that peaches maintain firm­ness better when stored in cool, very high humidity air. High airflow is useful for good heat transfer during cooling but reduces the localized air humidity during storage.