Grain post-harvest losses and their effect on food security: a case study of GMB storage facilities in Zimbabwe

Abstract

Post-harvest losses continue to be a major challenge to food security, grain quality and management of the strategic grain reserve in Zimbabwe. The GMB plays an important role in maintaining national grain reserves. However, storage related losses of Maize and selected traditional grains continue to compromise grain availability and economic efficiency. The study assessed the extent, causes and economic effects of post-harvest losses in selected GMB warehouses in Zimbabwe. The study was guided by four objectives namely to quantify quantitative post harvest losses in maize and selected traditional grains, to assess qualitative losses including infestation by insects, moisture deviation, broken percentage and aflatoxin contamination, to estimate economic costs associated with post-harvest losses and to assess the implications of storage losses on national food security and strategic grain reserve adequacy . A descriptive cross-sectional census design was adopted targeting all the 89 GMB depots across agro-ecological regions of Zimbabwe. Data were collected via structured online interviews with quality control personnel and by reviewing institutional records of grain storage. A total of 75 depots took part in the study, representing a response rate of 84.3%. For data analysis, descriptive statistics techniques such as frequencies, percentages, tables and a comparative analysis between the storage systems and agro-ecological regions were used. The results showed that maize had higher quantitative storage losses than traditional grains and many depots reported maize losses of 6-10%. The major cause of grain loss was insect infestation followed by moisture damage and inadequate handling. Depots in hotter agro-ecological regions had higher insect-related losses while facilities in humid regions had more moisture-related deterioration and aflatoxin risk. Silo complexes had less losses than storage facilities in warehouses. The study also revealed that post-harvest losses incurred significant economic costs due to decrease in quantity of grain, quality degradation, contamination and rejection of grain and increase storage management costs. Losses in storage also reduced the availability of grain in the strategic grain reserve system in Zimbabwe and contributed to food shortages during drought and deficit periods. The study concludes that post-harvest losses within GMB facilities are a serious threat to national food security and grain reserve efficiency in Zimbabwe. The study recommends upgrading of storage infrastructure, strengthening of pest and moisture management systems, adoption of climate-responsive storage technologies and improvement of environmental monitoring to reduce losses associated with storage.