Combination of hot water and ethanol to control postharvest decay of peaches and nectarines

Spores of Monilinia fructicola or Rhizopus stolonifer were immersed in water or 10% ethanol (EtOH) for 1, 2, 4, or 8 min at temperatures of 46 or 50 degrees C to determine exposure times that would produce 95% lethality (LT95). EtOH reduced the LT95 by about 90%. Peaches and nectarines infected with M. fructicola were immersed in hot water alone or with EtOH to control decay. EtOH significantly increased the central of brown rot compared to water alone. Immersion of fruit in water at 46 or 50 degrees C for 2.5 min reduced the incidence of decayed fruit from 82.8% to 59.3 and 38.8%, respectively Immersion of fruit in 10% ethanol at 46 or 50 degrees C for 2.5 min further reduced decay to 33.8 and 24.5%, respectively. Decay after triforine (1,000 mu g ml(-1)) treatment was 32.8%. Two treatments, 10% EtOH at 50 degrees C for 2.5 min and 20% EtOH at 46 degrees C for 1.25 min, were selected for extensive evaluation The flesh of EtOH-treated fruit was significantly firmer, approximately 4.4 N force, than that of control fruit among seven of nine cultivars evaluated. No other factor evaluated was significantly influenced by heated EtOH treatments. The EtOH content of fruit treated with 10 or 20% EtOH was approximately 520 and 100 mu g g(-1) 1 day and 14 days after treatment, respectively.