EVALUATION OF DIFFERENT PEST DISINFESTATION METHODS FOR RICE PACKINGS

ABDUL RAHIM MUDA, NIK MASDEK HASSAN and LIM GUAN SOON

SUMMARY

The relative efliciency of 5 disinFestation methods to control Sitophilus oryzae and Tribolium castaneum in rice packings, and their effects on grain nutritional content, fungal development and presence of aflatoxin on the grain were studied over 22 months storage period. Packaging rice in airtight laminated bags have shown to provide complete control against S. oryzae and T. castaneum over 19 months provided the airtightness can be maintained. The fluidized-heating method showed complete suppression of both species over 16 months but drastic loss in moisture, total protein, and vitamins (thiamine, riboflavin and niacin) was noted. With frying, fumigation, and microwave heating techniques, the more damaging. S. oryzae adults reappeared after 13, 7 and 1 month for all 3 treatment methods. With the exception of fluidized heated rice, losses, if any, in moisture and nutritional contents in rice by other methods were insignificant. Microwave heating, frying, fumigation, airtight plastic bagging and fluidized-heating recorded fungal infestation of 12.5%, 13.75%, 17.3%, 21.1% and 28.3% of grain assessed , respectively, compared to more than 50% fungal recovery in the pre-treatment assessment. The predominants pecies are Aspergillus candidus , A. niger, A. chevalieri, A . flavus, A. fumigatus, A. aculeatus, A . ruber and Penicillium spp. However aflatoxin was not detected.

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