Methyl bromide residues in fresh cherries: Effects of parameters of fumigation

Abstract

AbstractDeterminations were made of the desorption rate of residual free methyl bromide from fresh sweet cherries during the aeration period that followed fumigation with methyl bromide. The results showed that the desorption followed approximately pseudo‐first‐order kinetics. Ventilation rates during aeration, which were greater than or equal to the rates used at commercial fumigation chambers, had no effect on desorption rate. The concentration and persistence of residue was dependent on two parameters of the fumigation: the load factor, which is the ratio of the volume of cherries to the volume of the fumigation chamber, and the pulp temperature of the cherries. The relationship between load factor, pulp temperature and desorption rate was used to derive a mathematical model of the desorption of methyl bromide from cherries. The model gave good estimates of residue concentrations over a wide range of load factors, pulp temperatures and aeration periods, and was used to predict the length of the aeration period required to reduce the residue to a proposed tolerance of 0‐1 mg kg−1.