Excerpts from the report: Biphenyl has been used to control decay and soil-age in citrus fruit since Tomkins first reported its effectiveness in 1935. The commercial practice is to use kraft paper treated with biphenyl at the rate of 4 to 5 pounds per thousand square feet. This usage insures that an adequate quantity of biphenyl will be available during the marketing period for both domestic and overseas shipments. Two pads of this treated paper are placed in each carton of citrus fruit during packaging, placement varying with individual shippers. The legal tolerance for biphenyl residues in the United States in citrus fruits has been 110 p.p.m. since 1956. The European Economic Community (EEC) adopted a legal tolerance of 70 p.p.m. in 1968. The purpose of this study was to determine to what extent levels of biphenyl residue, decay, and soilage in oranges could be controlled (1) by the addition and removal of biphenyl after different intervals during storage, or (2) by the placement of barriers between the fruit and the biphenyl-treated pads. Another objective was to determine whether decay and soilage could be controlled without the use of biphenyl (1) by wrapping oranges individually in polyethylene film and storing, and (2) by storing unwrapped fruit with polyethylene-coated kraft paper placed between the layers of fruit. Length and temperatures of storage simulated those required for shipment to western European ports and distribution to the various EEC markets.
