Postharvest Decay, Respiration, Ethylene Production, and Quality of Peaches Held in Controlled Atmospheres with Added Carbon Monoxide1

The effects of 11% CO added to air or to 4% O2 ± 5% CO2 on brown rot development, respiration, ethylene production, firmness, color, composition, and internal breakdown of peaches [Prunus persica (L.) Batsch cv. Fay Elberta] were evaluated during holding at 5°C for 14 days followed by 3 days at 20° in air. The addition of 11% CO to 4% O2 ± 5% CO2 atmospheres completely inhibited growth of Monilinia fructicola (Wint.) Honey in vitro and in vivo. However, the normal rate of rot development resumed once inoculated plates and fruits were transferred to air at 20°. CO added to air stimulated CO2 and C2H4 production and enhanced softening, but its effects were insignificant when added to 4% O2, 5% CO2, or their combination. CA treatments without CO decreased respiration and C2H4 production rates and delayed softening. Differences among treatments in composition were small. Internal breakdown incidence and severity were slightly reduced by CO and increased by CO2.