Survey of o-phenylphenol residues found in marketable citrus fruit.

Abstract

AbstractResidues of o‐phenylphenol (OPP) were determined in peel, pulp and the whole fruit of Shamouti and Valencia oranges, grapefruits and lemons which were treated under industrial conditions with solutions of sodium‐o‐phenylphenate (SOPP). The OPP residues found in the peel of the different species of citrus fruit varied from 5.4 to 26.1 ppm OPP. In many cases OPP residues were not detectable in the pulp, and in other cases traces and 0.4 ppm of OPP were found.The residues in the whole fruit were found to range from 1.8 to 8.3 ppm, with 80% of the samples analysed containing less than 5 ppm. These amounts were within the tolerance limits generally established for residues of OPP in citrus fruit (10 and 12 ppm of OPP).The SOPP concentration of the disinfectant solutions ranged from 0.24 to 0.55% SOPP.4H2O and had little effect on the OPP content of the fruits. The fruits which were treated at a pH below 11.6 usually contained more OPP than those treated at pH values between 11.6 and 12.3.