When control avocado slices were re-measured at= 17 th h after HPP treatment, there had been a reduction in co2 production to =30% of the value with the 1-h measurement ( dropping from 1.57 to 0.54 μmol kg-1 h-1;Fig. 3a). carbon dioxide production of fruit in the 200 MPa treatments was again not significantly lower than that of the controls, but 300 and 400 MPa treatments did reducs co2 produstion, and the concentration at 500-600 were very low (0.02-0.05 μmol kg-1 h-1).we suggest that part of the drop in co2 over 17 h for the control treatment reflects diffusion of co2 that had built up in the bag around the slices between the time of sealing and treatment, but that it also reflects a reduction of respiration rate (and therefore very minimal metabolic activity).