Test Shipments of Papayas with Special Reference to Storage Decay Control

Abstract

A condition for the certification of fresh papayas shipped to the mainland United States, as set forth by the USDA Bureau of Entomology and Plan t Quarantine, is that these fruits be either fumigated with EDB (ethylene dibromide) or vapor-heat treated to kill eggs and larvae of fruit flies. The EDB treatment, so far as is known, has had no adverse effect on fruit quality, while the vapor-heat treatment has at times been known to considerably reduce fruit quality. Shippers using the EDB method have found, however, that considerable percentages of EDB-treated papayas shipped from Hawaii to the West Coast decayed either during the transit period or soon after arrival on the market. Papayas shipped by the vapor-heat treatment were comparatively free from storage decay, and as a result they found wider market acceptance than the EDB-treated fruits. Akamine and Arisumi recommended the hot water treatment as a control measure for anthracnose, which is a major cause of storage decay in EDB treated papayas. They found that the development of this decay can be suppressed by immersing papayas in hot water at temperatures from 110° to 120° F. for 20 minutes. Shoji in his storage studies of vapor-heat treated and EDB treated fruits found that the anthracnose development of ripe fruits was held at a minimum when the fruit was stored at 45° F., and at a maximum when stored at 65° F. or at room temperatures (70°- 80° F.). Test shipments from Hawaii to San Francisco were designed to test some of the treatments and methods recommended by Akamine and Arisurni and Shoji under actual shipping conditions .