Emerging global technological challenges in the reduction of post-harvest food losses

Abstract: The adverse effects of pesticide residues in food and the environment resulted in imposing strict limitations on pesticide registration by regulatory agencies. On the other hand consumer demand for chemical-free and insect contamination-free products is a general tendency with which the food industry finds it difficult to conform. This paper reviews the emerging global technological challenges in the reduction of post-harvest food losses. In many countries, storage insects like Rhyzopertha dominica, Tribolium castaneum and Sitophilus oryzae have been reported to develop resistance to contact insecticides and to the conventionally used phosphine gas. Phosphine fumigation is a common treatment where three important points deserve attention: a) sufficient gas tightness, the lack of which leads to insect resistance; b) recirculation to obtain uniform gas concentration; and c) sufficient exposure time for complete control. Other registered fumigants suffer from the limitation that they may be useful for application using special equipment or under specific conditions. The most common non-chemical alternative for storage of cereals is the use of aeration systems during the winter and refrigerated aeration in the summertime with the objective to achieve temperatures of less than 18 °C to reduce insect activity. In the summertime, refrigeration provides an excellent solution for quality maintenance of grain. However, aeration has a limited effectiveness in tropical climate areas. Field trials have demonstrated the efficacy of thermal disinfestation in flourmills and in the dry fruit industry, particularly for dates. Other gaseous treatments that have successfully replaced fumigants are the manipulation of modified atmospheres (MAs) through the use of biogenerated MAs and hermetic storage, for insect control and for quality preservation of stored cereals, cocoa beans, and high moisture corn. MA has niche application because of its higher cost than conventional fumigation using phosphine.