Radiation disinfestation of used packagings: irradiation trials with electron beams

Used bags, sacks and other packagings are often infested with insects and mites - pest of stored products. Such packagings provide a source of infestation of a new lot or unit of agricultural products. Cleaning of repeatedly used packages is the most important preventive method. After using, the bags and sacks should be carefully beaten with a mechanical or hand beater. When pests are found, the packages should be disinfested with hot air or hot water. Larger numbers of bags are usually fumigated in a special fumigation chamber. Disinfestation by radiation processing is potentially a feasible substitute for chemical fumigation. In the present paper trials of radiation disinfestation of used bags are described and discussed. Information about using electron beams for pest disinfestation of jute and polyvinyl chloride bags (plastic bags) is provided. The absorbed dose is the most important irradiation process parameter. The lethal effects equivalent to chemical insecticides are obtained by high doses of ionizing radiation. Control of insect and/or mite infestation of the repeatedly used packagings may be secured by ionizing radiation applied at 2-3 kGy. These doses result in complete mortality of stored product pests within a few days. The radiation must penetrate deeply into the target product at sufficient level. Gamma rays and X-rays penetrate into the treated products easily but electron radiation penetrating is much lower, depending on electron energy applied. The results of this study indicate that bags made of polyvinyl chloride may be disinfested with electron beams when are created as separate units or batches up to 50 bags. Penetrability of jute bags is lower than the plastic bags. Therefore the jute bags should be irradiated with electrons as batches containing no more than 30 bags. (author)