Disinfestation of stored dates using microwave energy

Abstract

This study was conducted to determine the mortality of two common insect species in stored dates using a microwave oven operating at 2450 MHz. Adults of Tribolium castaneum (Herbst) and Oryzaephilus surinamensis (L.), and larvae of T. castaneum (15 days) were used to internally infest stored un-pitted dates and then subjected to microwave treatment at 180, 300, 600 or 800 W power for 20, 30 or 40 s. Complete mortality was achieved for adults of both insects and larvae of T. castaneum when the power was 800 W and the exposure time was 30 or 40 s. Mortality of T. castaneum larvae was also 100% when the power and exposure time were 600 W and 40 s, respectively. The quality attributes of the microwave-treated dates (in which 100% mortality was achieved) were compared with untreated dates. Instrumental evaluation of texture profiles revealed that microwave disinfestation did not affect hardness, adhesiveness, springiness, cohesiveness and chewiness. Microwave disinfestation did not affect the sensory attributes or the surface color of date fruits. The moisture loss during microwave treatment was between 1.0 and 1.5 percentage points. Further investigations are required to determine the capability of microwave disinfestation for packed dates and other stored product insects and life stages.