Comparative Effects of Applying Imazalil By Dipping or By Incorporation Into the Plastic Film On Decay Control, Distribution and Persistence of This Fungicide in Shamouti Oranges Individually Seal-Packaged

Abstract

Seal-packaging presents another practical way of providing fungicides to individual fruits by incorporating the fungicide in the packaging film. Imazalil-containing film prevented the development of Penicillium digitatum and significantly inhibited that of Diplodia natalensis and Alternaria citri in petri dishes; this indicates that imazalil exerts its action through the vapor phase. Film containing imazalil (at concentration of 2000μg/g) markedly reduced the decay of Shamouti oranges inoculated with P. digitatum if the sealing was done immediately following the inoculation, and only slightly if sealing was delayed 24 h. Disinfection with sodium orthophenylphenate combined with sealing in imazalil-containing film provided further reduction in decay, even if the film was applied 24 h after inoculation. The effectiveness of fungi cides, whether applied to the fruit directly or in the film, was not affected by sealing. Distribution of imazalil among the film, flavedo and albedo was monitored through out the storage period of sealed fruit. The film could serve as a reservoir releasing the fungicide gradually, so that its antifungal activity may replace that previously provid ed by waxing without the risk of excessive toxic residues.