Influence of cooling and temperature maintenance on the quality of California grown stone fruit

Abstract

Stone fruits require rapid cooling within a few hours of harvest. High temperature and cooling delays can speed fruit deterioration from several causes. Flesh softening is most rapid at temperatures between ≈4 and 38°C, where ethylene sensitivity is greatest. Water loss is related to exposure time and the magnitude of water vapour pressure difference between fruit and environment. Internal breakdown, a low temperature injury problem, is aggravated in California by high temperature delays before cooling. Fruit rot organisms spread most rapidly at warm harvest temperatures and are slowed or stopped at near 0°C. When packing is delayed, then cooling before packing is essential. Because injury susceptibility is least at intermediate temperatures (5-20°C), fruit may be cooled to 5-10°C for next day packing, but should be cooled to near 0°C for longer delays. Regardless of prior cooling, the warming that will occur during packing makes essential final cooling to near 0°C following packing. Methyl bromide fumigation, if needed for quarantine treatment, should occur before cooling because warm fruit is less injured and fumigant doses are lower at warmer temperatures. © 1987.