Residues in apples and their packaging following fumigation with methyl bromide

Abstract

Apples (cv. Granny Smith) were fumigated with 40 g methyl bromide/m3 for 2 h at 17°C, then aerated for 2 h and stored for 10 days at 1°C as a proposed quarantine schedule for export to Japan. Residues of methyl bromide decreased from 0.1 µg/g following fumigation and cold storage to <0.002 µg/g after a further 20 days at 1°C (to simulate shipping time to Japan). Statistical analysis estimated that methyl bromide residues would decrease to 0.001 µg/g after 14.2 days storage at 1°C after fumigation. Methyl bromide residues in apple carton materials decreased to <0.01 µg/g after 7 days at 1°C, and to below the detection limit (0.002 µg/g) after 7 extra days storage at 1°C. Inorganic bromide residue after fumigation and cold storage for 30 days was 3.9 µg/g. This was less than the maximum residue limit (5 µg/g) set by the US Food and Drug Administration.