Covid-19 and Post-harvest food protection

By Dr. Wolly Wijayaratne Senior Lecturer in Pest Management Faculty of Agriculture, Rajarata University of Sri Lanka.

Currently the entire world has been affected by Covid-19 pandemic situation. In a situation where the agricultural operations are not performed on regular basis as it was previously, decline in the food production is expected. Therefore, the protection of limitedfood available becomes mandatory. It should be noted that the losses occurred during post-harvest operations of agricultural commodities is higher in the developing world including Sri Lanka. 

Among the numerous factors that cause post-harvest losses of agricultural commodities, insect infestation is a major factor. According to the published reports, the damage caused by insects to the cereals (paddy, maize, millet, etc.), pulses (green gram, cowpea, etc.), oil crops (eg. sesame) and processed food during post-harvest stages can be as much as 50% of the total harvest in the developing countries. The damages include quantitative losses as well as qualitative losses such the nutrient loss, seed germination loss, poor taste, bad smell, grain discoloration, development of fungus, and finally the economic loss due to the reduced market value. These damages to stored food is observed at each location in the post-harvest distribution channel from the farmer to the consumer. Accordingly, the insect infestation of grains can be observed in the farmer’s field, grain stores, feed/flour mills, wholesale and retail markets as well. In the past, insect deterioration of food in the above places has been reported from time to time. Therefore, the due attention on this issue is highlighted under the present circumstances in order to ensure the maximum protection of available food.

In Sri Lanka, the annual losses due to the damage occurred during post-harvest operations amount to Rs. 18-20 billion. Studies conducted in Sri Lanka have demonstrated that at least¾ of the damage occurred in grains during storage is due to insect infestation. Therefore, more attention must be paid to control insect infestation of grains, pulses and oil seeds during storage.

These remedial measures include number of steps including maintaining proper store hygiene, regular inspection of stored grains, selection of insect-free grains for storage, deprivation of ecological factors that favour the growth and development of insect population and adoption of proper control measures when the insects are detected.Removal of debris and pre-infested batches of grains, sun drying of storage bags and wooden structures used for stacking of grains before reuse, proper ventilation inside the storage structures would also be helpful practices. In general, the tropical weather (temperature and humidity) conditions favour the development of insect population inside stores.As the stored food is meant for subsequent consumption, treatments adopted need to ensure the safety of consumers at the post-treatment stage as otherwise the same may cause short-term and long-term health issues. Therefore, protection of stored food from alleged insects needs to be handled in a scientific manner and under the supervision of scientists who have the specific training on the same.

Under the current circumstances where the national food security is highly concerned, the due attention of relevant parties is drawn on the above factors in minimizing post-harvest losses of available food with emphasis on the protection from insect infestation.