Cowpea is a vital source of dietary protein for millions of people across sub-Saharan Africa. The crop is typically grown by smallholder farmers for household consumption and to generate income through sales. However, postharvest losses are perceived to be high affecting both the quantity and quality of cowpea available. To design targeted loss reduction activities, understanding is needed of the extent, causes and activity stages during which losses occur. The cowpea postharvest systems of 120 farming households across four agro-ecological zones of Benin were explored across two years through interviews. Additionally, directly measured loss assessments at each activity stage from harvest to store loading and during a 6-month storage period were done with a subset of these households. Postharvest activities were mainly done manually. Storage practices included storing untreated grains in woven polypropylene (PP) bags or plastic or metal drums, or treatment of cowpea grains with synthetic chemical pesticide dust, a fumigant or dried chilli and storage in PP bags. Measurement found the cumulative mean quantity losses from harvesting through six months of storage were 19.03-21.96 % with the highest proportion of these losses occurring during harvesting (3.34-3.89 %), drying of pods (1.96-2.05 %), threshing (3.22-3.71 %), and storage (10.14-12.01 %). Loss levels were similar between years. Loss causes included rainfall during harvesting and/or drying, poor threshing methods, labour shortages, storage insect pest attack and rotting. An opportunity clearly exists for targeted multi-stakeholder participatory action research to codevelop affordable and acceptable ways of reducing these significant losses of such nutritionally and economically important grain legumes.

As food systems across sub-Saharan Africa transform and urbanise, demand for all-year-round supplies for the raw materials is increasing. This demand can be met through combinations of staggering crop production, purchasing from diverse geographical areas, and storing produce. Focusing on the increasing use of orangefleshed sweetpotato root puree in vitamin-A-rich food products, we ran a series of storage trials in Kenya to investigate whether commercial-scale fresh orange-fleshed sweetpotato storage could provide a stable supply of roots for puree production. The trials studied storage of roots of two sweetpotato varieties (Kabode and Vita), using washed versus unwashed roots in wooden crates, and mains grid power versus off-grid solar-powered storerooms for four-months. Following curing at 30 degrees C, roots were stored at 20-23 degrees C, and quality assessed. After four months storage, 54-59 % (Kabode) and 63-83 % (Vita) of initial root weight remained suitable for processing into puree. However, weevil and sprouting problems occurred. Vita outperformed Kabode for most criteria. Neither root washing nor different storerooms had a consistent effect on root quality. Subsequent trials in a solar-powered store investigated if lower temperatures of <= 15 degrees C and 90 % rh, with pre-harvest dehaulming could reduce weevil development, sprouting and rotting in stored roots. While control of sprouting and weevil damage was achieved and dehaulming improved stored root quality, while washing reduced it, high incidence of rotting and root weight loss occurred. Increasing store ventilation did not reduce rotting. We conclude that further trials with well controlled storage environments are required to understand how raw root quality, dehaulming, harvesting and handling practices, curing conditions, air exchange, and packaging materials affect quality during fresh root storage.

Alternative plant and seaweed protein sources other than soy and pea have gained significant interest as sustainable replacements of animal proteins in the last decades. However, despite a large food safety literature base, there are concerns about their food safety risks. The current study aims to synthesize the existing knowledge and gaps on safety risks associated with brewers' spent grain (BSG), grapes, hazelnuts, potatoes, pumpkins, and seaweed. A systematic review between 2003 and 2023 was conducted in the PubMed database to identify microbial, chemical, mycotoxins, heavy metals, and allergenic risks in the key commodities. The records obtained were exported into an online reference management platform, screened by inclusion and exclusion search strings, and the duplicates were removed. Finally, two reviewers assessed the eligibility of the full-text articles. The findings demonstrated that 9127 papers were identified, and 1639 of them were left for eligibility assessment. The reviewers finally included 144 articles. Amongst the commodities, the most safety studies were on grapes, with 55 papers, followed by potatoes (n=38), seaweed (n=21), hazelnuts (n=19), pumpkin (n=9), and BSG (n=2), respectively. Based on the risk type, heavy metals were the most studied ones, with 49 papers, followed by mycotoxins (n=31), microbial risks (n=23), chemical contaminants (n=21), and allergenic risks (n=20), respectively. To meet the growing need for plant and seaweed proteins, their food safety aspects should be extensively studied to deliver safe, healthy, and affordable substitutes based on robust safety standards.

Reducing postharvest losses (PHLs) is an integral part of sustainable and resilient food systems. This study updates a systematic scoping review of PHL reduction interventions from the 1970s to 2019, for 22 crops across 57 countries in sub-Saharan Africa (SSA) and South Asia. This 2024 update identified 123 studies which met the inclusion criteria bringing the total evidence-base to 457 studies and 2187 interventions studied. The interventions were predominantly tangible technologies (87.7 %) followed by handling practice changes (10.1 %). Storage technology interventions mainly targeting farmers continued to dominate the evidence-base (71.3 %). Cereal interventions dominated (42.4 %), particularly maize (26.3 %) mostly in SSA. For cereals and legumes, hermetic storage bags were widely studied, and mechanised threshing and solar drying evidence had expanded. New evidence on postharvest training bundled with various technologies particularly for aflatoxin management was reported. Fruits (20.8 %), particularly citrus and mango in India, were the second most studied group, with storage protectants, particularly waxes or coatings, structures for cooling and packaging being common. Root and tuber crops accounted for 17.0 % of interventions, principally potato in India, vegetables (11.4 %), mainly onion and tomato, and legumes (8.4 %). Geographically, India then Nigeria had the most studies while 23 countries had none. Socio-economic outcomes and uptake factors are examined. This analysis highlights the continued need for systematic assessment of interventions along value chains over multiple seasons and sites, targeting stakeholders beyond farmers, with more studies on training, finance, infrastructure, policy and market interventions, and increased emphasis on social, economic and environmental outcomes of postharvest interventions.

Poor storage methods lead to high postharvest losses in maize, an essential staple in sub-Saharan Africa. Smallholder farmers' knowledge and awareness of postharvest nutritional losses (PHNLs), practices regarding maize grain storage, and factors influencing use of improved storage protection practices were investigated in two districts in Zimbabwe through a cross-sectional field survey of 331 households randomly selected from lists of farmers' names kept by local extension staff. A multistage sampling technique was used involving purposively selecting the study districts then randomly selecting the study wards, the villages and the households. Twenty eight key informant were purposively selected being officers and stakeholders working or residing in the two districts and involved in postharvest and nutrition issues. The most commonly used storage practices were the admixture of maize grain with synthetic grain protectant pesticides followed by storage of untreated grain in polypropylene bags. Highly toxic pesticides, such as Cabaryl 85 WP and Acetamiprid 20 SP, which are not registered for stored food grain treatment, were being applied by 14.6% of the farmers to protect their grain from insect attack. We developed a PHNL knowledge index that measured farmers' nutritional knowledge and awareness of PHNL. Level of education and district positively correlated with farmers' PHNL knowledge (p < 0.05), whereas the opposite was found for farmers' age (p < 0.05). Multinomial logistic regression analysis showed that use of grain storage protection practices was positively related to farmers' age, total maize grain production, education level and PHNL knowledge (p < 0.05). Older farmers were less likely to use non-recommended chemicals to protect their maize grain during storage. Farmers' education level and total maize grain production were positively associated with higher use of synthetic pesticides, while PHNL knowledge was associated with the use of traditional grain protectants (p < 0.05). Training on grain storage management, especially safe grain storage protection practices and PHNLs, is essential to contribute towards household food and nutrition security.

Berbere, the hot pepper spice, is a central ingredient in Ethiopian cuisine. This study aimed to deepen understanding of the agricultural and postharvest handling practices and incidence of aflatoxins and ochratoxins at different stages of the domestic berbere (Capsicum frutescens) value chain in the Amhara region of Northern Ethiopia. The main actors in the berbere value chain in Ethiopia are farmers, assemblers, wholesalers, retailers, industrial processors, and domestic consumers. A series of semi-structured questionnaires were developed and used to interview 90 stakeholders from across these different value chain stages to learn about their berbererelated activities and challenges. Additionally, a random sampling method was used to collect 100 berbere samples (80 samples of whole dry berbere pods and 20 samples of berbere powder) from across the different focal value chain stages (harvesting, storage, processing, and retail) for analysis to determine whether aflatoxin and ochratoxin were present above the maximum recommended thresholds. In the Amhara region, most farmers typically cultivate berbere on areas of 0.5-1 ha of farmland. The berbere harvest is done manually, and the chilli pods are then spread directly on the ground to sun dry. Such drying practices increase the risk of contamination of the produce by dust, debris, and soil-borne fungi. Assemblers purchase berbere from the farmers, the pods are then sorted by variety and packed in woven polypropylene bags which are then heaped in store rooms. All the berbere samples, from each stage of the value chain analysed were found to test positive for mycotoxins, exhibiting levels of >20 ppb and >2 ppb of total aflatoxin and ochratoxin, respectively. The promotion of a range of integrated pest and postharvest management actions with the different value chain actors are recommended to improve the quality and safety of berbere within these important domestic value chains.

Food loss and waste (FLW) reduction is key to transforming food systems to deliver food security, while responding to climate change and reducing other environmental impacts. Food production and postharvest systems differ with location, reflecting the diversity of agroecological and socio-economic environments and the drivers influencing them. The interactions between drivers and environments, practices and products influence food systems and their greenhouse gas emissions and other related environmental impacts. These factors also influence the level of food loss during or after harvest, or food waste at retail or consumer level. This think-piece examines the relationships between climatic change, the environment, and FLW within a broader food systems framework. We use the case study of maize in Malawi to explore these relationships. This analysis unpacks the issues and suggests an approach for supporting decision-makers in making a more informed assessment of how to reduce FLW, taking into account the complexity of food systems, their multiple drivers of change, diverse stakeholder interests/influence, and the need to operate with very incomplete knowledge.

Smallholder farmers in sub-Saharan Africa store harvested maize to provide food stocks between harvest seasons, which may be up to 12 months apart. Stored maize is highly susceptible to insect pest damage, hence the need for stored grain protection technologies such as hermetic bags. The current study evaluated the efficacy of five brands of hermetic bags in storing three maize varieties under two contrasting agro-ecologies in Guruve and Mbire districts of Zimbabwe, for two storage seasons. The hermetic bag treatments evaluated included: GrainPro Super Grain bag (SGB) IVRTM, PICS bag, AgroZ (R) Ordinary bag, AgroZ (R) Plus bag and ZeroFly (R) hermetic bag, which were compared to grain stored in a polypropylene bag either untreated (negative control) or following admixture with a synthetic pesticide treatment, Actellic Gold Dust (R) (positive control). The maize varieties included a white hybrid, a pro-vitamin A biofortified orange and a local variety. All the hermetic bag treatments out-performed the synthetic pesticide in limiting grain damage and weight loss during storage. No significant difference in grain damage or weight loss was observed among the hermetic bags. However, rodents punctured some hermetic bags; therefore rodent control is recommended. A positive correlation with grain damage and weight loss for all three maize varieties was found for Sitophilus zeamais, Sitotroga cerealella, Tribolium castaneum and Cryptolestes spp adult numbers. Significantly higher insect damage and weight loss (P < 0.001) occurred in the white hybrid maize than in the other two varieties. The results confirmed that regardless of brand, all the hermetic bags tested can be recommended for smallholder farmer use to limit postharvest storage losses, avoid pesticide use, and support food and nutrition security.

Field evaluation of six grain storage technologies under hot and arid conditions (32–42 °C; rainfall < 450 mm/year) in two locations in Zimbabwe were conducted over two storage seasons. The treatments included three hermetic technologies (Purdue Improved Crop Storage bags, GrainPro Super Grainbags, metal silos); three synthetic pesticide-based treatments; and an untreated control, all using threshed sorghum grain. Sampling was at eight-week intervals for 32 weeks. Highly significant differences (p < 0.01) occurred between hermetic and non-hermetic treatments regarding grain damage, weight loss, insect pest populations, and grain moisture content; with the hermetic containers exhibiting superior grain protection. Weight losses were low (< 3%) in hermetic treatments compared to pesticide-based treatments (3.7 to 14.2%). Tribolium castaneum developed in metal silos, deltamethrin-incorporated polypropylene bags and a pesticide treatment containing deltamethrin 0.13% and fenitrothion 1% while Sitotroga cerealella developed in a pesticide treatment containing pirimiphos-methyl 0.16% + thiamethoxam 0.036%. Mechanisms of survival and development of these pests in the tested treatments and under similar climatic conditions need further elucidation. These hermetic technologies can be successfully used by smallholder farmers in developing countries as alternatives to synthetic pesticides for protecting stored-sorghum grain under hot and arid climatic conditions to attain household food security. To our knowledge, this is the first published study on modern hermetic storage of sorghum grain under typical smallholder storage conditions and involving stakeholders.

The impacts of climate-related risks on rural-urban linkages and the food systems on which urban settlements depend are poorly understood. This study analysed (i) the climate trends for Blantyre City and rural Chikwawa district in Malawi, (ii) the sources of foods typically consumed in these locations, (iii) the implications of flooding following Tropical Cyclone Idai on urban and rural households' interconnected agri-food systems and food security. Although floods were reported to cause both positive and negative effects on food production; food flows between rural and urban areas; and household food security, the negative effects (i.e. destruction of crops, homes and transport routes; higher food prices) outweighed the positives. In both rural and urban areas, poorer households were disproportionately affected resulting in reduced dietary diversity and food intake, shifts to consumption of cheaper foods, and requests for emergency food donations. Given the rapid rate of urbanisation, better understanding of food security amongst urban households is required. Following extreme events such as flooding, special attention needs to be directed to assessing and addressing food availability, access and consumption challenges in both urban and rural areas reliant on interconnected agricultural and food flows, and particularly in poor households.

The impacts of climate-related risks on rural-urban linkages and the food systems on which urban settlements depend are poorly understood. This study analysed i) the climate trends for Blantyre City and rural Chikwawa district in Malawi, ii) the sources of foods typically consumed in these locations, iii) the implications of flooding following Tropical Cyclone Idai on urban and rural households interconnected agri-food systems and food security. Although floods were reported to cause both positive and negative effects on food production, food flows between rural and urban areas, and household food security; the negative effects (i.e., destruction of crops, homes and transport routes; higher food prices) outweighed the positive. In both rural and urban areas, poorer households were disproportionately affected resulting in reduced dietary diversity and food intake, shifts to consumption of cheaper foods, and requests for emergency food donations. Given the rapid rate of urbanisation, better understanding of food security amongst urban households is required. Following extreme events such as flooding, special attention needs to be directed to assessing and addressing food availability, access and consumption challenges in both urban and rural areas reliant on interconnected agricultural and food flows, and particularly in poor households.

The significance of urban agriculture is increasingly being recognised across the globe. Urban agriculture's contribution to food security and poverty reduction, especially for the urban poor, has received increasing attention in urban policy discourses (Satterthwaite et al. in Adapting to climate change in Urban areas; the possibilities and constraints in low- and middle-income countries. IIED, London, 2007; Mutonodzo in Agriculture in urban planning: generating livelihoods and food security. Earthscan, London, 2009; Mkwambisi in Agriculture in urban planning: generating livelihoods and food security. Earthscan, London, Mkwambisi 2009). The impacts of climate change, climate variability and urban growth reduce the benefits derived from agro ecosystem services in peri-urban areas in most developing countries. Peri-urban areas play a significant role in providing similar to 80% of the vegetables consumed in urban areas of Malawi. However, the vegetable production is dependent on stream water or residual moisture from wetlands, which are being affected by climate change. This study investigated the viability of multi-stakeholder experimentation with sustainable technologies for improving vegetable production in a peri-urban setting experiencing water shortages due to climate change and variability in the Mulanje district in Southern Malawi. Using a participatory action research (PAR) approach, farmers, researchers, extensionists and village leaders worked together to source, test and evaluate various different horticultural production practices. Over a two-year period, they experimented with technologies such as bag (vertical) gardening, differential use of manure and fertiliser, new crops and crop varieties, seed bed preparation techniques and judicial use of pesticides. Those practices identified as successful in 2011 were replicated in 2012 for further evaluation. In general, the study found considerable improvements in vegetable production resulting from the improved agronomic practices. Further, many farmers found bag gardening more convenient due to reduced irrigation requirements, lower labor demands, all year round seasonal production, ease of access and crop security. Improved quality of produce, earlier harvest and increased total number of harvests of leafy vegetables due to manure incorporation, use of improved varieties and high yields in general were among other advantages that were realised. In addition, the technologies promoted minimal use of chemicals, which resulted in reduced seepage of inputs, thereby maintaining agro-ecosystem health. Most communities in the area have adopted the technologies as strategies for climate change adaptation. Scaling up these practices can therefore improve vegetable supply challenges arising from urbanisation, climate change and variability while reducing impacts on agro-ecosystem services.

Prostephanus truncatus is a notorious pest of stored-maize grain and its spread throughout sub-Saharan Africa has led to increased levels of grain storage losses. The current study developed models to predict the level of P. truncatus infestation and associated damage of maize grain in smallholder farmer stores. Data were gathered from grain storage trials conducted in Hwedza and Mbire districts of Zimbabwe and correlated with weather data for each site. Insect counts of P. truncatus and other common stored grain insect pests had a strong correlation with time of year with highest recorded numbers from January to May. Correlation analysis showed insect-generated grain dust from boring and feeding activity to be the best indicator of P. truncatus presence in stores (r = 0.70), while a moderate correlation (r = 0.48) was found between P. truncatus numbers and storage insect parasitic wasps, and grain damage levels significantly correlated with the presence of Tribolium castaneum (r = 0.60). Models were developed for predicting P. truncatus infestation and grain damage using parameter selection algorithms and decision-tree machine learning algorithms with 10-fold cross-validation. The P. truncatus population size prediction model performance was weak (r = 0.43) due to the complicated sampling and detection of the pest and eight-week long period between sampling events. The grain damage prediction model had a stronger correlation coefficient (r = 0.93) and is a good estimator for in situ stored grain insect damage. The models were developed for use under southern African climatic conditions and can be improved with more input data to create more precise models for building decision-support tools for smallholder maize-based production systems. (C) 2020 Elsevier Ltd. All rights reserved.

Our understanding and prevention of postharvest losses are critical if we are to feed a growing global population. Insect infestation-related losses of stored commodities are typically considered only in terms of quantitative, physical weight loss. Insect infestation affects the nutritional value and some nutritional components are impacted more severely than others. We infested maize and cowpea grain with commonly occurring stored product insect pests, and mapped infestation levels against nutritional composition over a 4-to-6 month storage period to analyse how insect infestation relates to different macro- and micro-nutrient contents. Insect infestation decreased the carbohydrate content of the stored grains, causing a relative increase in the proportion of protein and fibre in the remaining grain, and moisture content also increased. Sitophilus zeamais preferentially fed in the floury endosperm of maize, resulting in more carbohydrate loss relative to protein loss. Conversely, Prostephanus truncatus consumed the germ and endosperm, disproportionately reducing the fat, protein, iron and zinc grain contents. Nutrients are distributed more homogenously within cowpea than in maize grains, but Callosobruchus maculatus infestation increased the relative protein, fat, iron and zinc to carbohydrate ratios. This indicates how the nutrient content of insect-infested stored grain depends upon the grain type, the infesting insect, and the infestation level. Insect infestation therefore has consequences for human nutrition beyond those of grain weight loss. Using data collected on the changing nutritional composition of grain over time, with and without insect infestation, we modelled the associations between infestation and nutritional quality to predict estimated nutritional losses that could be associated with consumption of insect-infested stored maize and cowpea.

Smallholder farmers constitute the bulk of staple grain producers in developing countries but there is inadequate support in the postharvest management (PHM) phase of the food supply chain. Several effective PHM technologies have been developed to tackle food grain losses. However, minimum impact has been realised mainly because the technologies have not been widely adopted for various reasons. This chapter analyses PHM practices, available technologies and delivery models, and examines factors causing non- or poor adoption of the technologies in developing countries. Missing parts of the PHM jigsaw puzzle are identified and possible practical solutions offered. The chapter proposes strategies to support smallholders in building sustainable and robust PHM interventions to enhance technology uptake for effective reduction of postharvest loss in quantity and quality. There is no “silver bullet” in addressing the diverse and complex grain postharvest challenges faced by smallholder farmers, and associated service-providers in developing countries.

Cowpea (Vigna unguiculata L. Walp) grain is an important source of protein for smallholder farmers in developing countries. However, cowpea grain is highly susceptible to bruchid attack, resulting in high quantitative and qualitative postharvest losses (PHLs). We evaluated the performance of five different hermetic bag brands for cowpea grain storage in two contrasting agro-ecological zones of Zimbabwe (Guruve and Mbire districts) for an 8-month storage period during the 2017/18 and 2018/19 storage seasons. The hermetic bag treatments evaluated included: GrainPro Super Grain bags (SGB) IVRTM; PICS bags; AgroZ (R) Ordinary bags; AgroZ (R) Plus bags; ZeroFly (R) hermetic bags. These were compared to untreated grain in a polypropylene bag (negative control) and Actellic Gold Dust (R) (positive chemical control). All treatments were housed in farmers' stores and were subjected to natural insect infestation. Hermetic bag treatments were significantly superior (p < 0.001) to non-hermetic storage in limiting grain damage, weight loss and insect population development during storage. However, rodent control is recommended, as rodent attack rendered some hermetic bags less effective. Actellic Gold Dust (R) was as effective as the hermetic bags. Callosobruchus rhodesianus (Pic.) populations increased within eight weeks of storage commencement, causing high damage and losses in both quality and quantity, with highest losses recorded in the untreated control. Cowpea grain stored in Mbire district sustained significantly higher insect population and damage than Guruve district which is ascribed to differences in environmental conditions. The parasitic wasp, Dinarmus basalis (Rondani) was suppressed by Actellic Gold Dust (R) and all hermetic treatments. All the hermetic bag brands tested are recommended for smallholder farmer use in reducing PHLs while enhancing environmental and worker safety, and food and nutrition security. (c) 2020 Elsevier Ltd. All rights reserved.

Reducing postharvest losses (PHLs) of food crops is a critical component of sustainably increasing agricultural productivity. Many PHL reduction interventions have been tested, but synthesized information to support evidence-based investments and policy is scarce. In this study, PHL reduction interventions for 22 crops across 57 countries in sub-Saharan Africa and South Asia from the 1970s to 2019 were systematically reviewed. Screening of the 12,907 studies identified resulted in a collection of 334 studies, which were used to synthesize the evidence and construct an online open-access database, searchable by crop, country, postharvest activity and intervention type. Storage technology interventions mainly targeting farmers dominated (83% of the studies). Maize was the most studied crop (25%). India had the most studies (32%), while 25 countries had no studies. This analysis indicates an urgent need for a systematic assessment of interventions across the entire value chain over multiple seasons and sites, targeting stakeholders beyond farmers. The lack of studies on training, finance, infrastructure, policy and market interventions highlights the need for interventions beyond technologies or handling practice changes. Additionally, more studies are needed connecting the impact of PHL reductions to social, economic and environmental outcomes related to Sustainable Development Goals. This analysis provides decision makers with data for informed policy formulation and prioritization of investments in PHL reduction.

This chapter reviews food losses and waste in sub-Saharan Africa. It gives a general introduction to the terms ‘food loss’ and ‘food waste’ and how they differ. It focusses on the postharvest food losses occurring in sub-Saharan Africa and compares ‘objective measurements’ with ‘perceptions’ of food losses occurring during and after harvest. It also provides an overview of what information is already available regarding food losses and waste in sub-Saharan Africa. The chapter goes on to discuss various challenges and initiatives in reducing food losses and waste and concludes by providing a general summary and several resources for further information.

Field data on current crop postharvest management practices and perceptions from smallholder farming communities in an increasingly variable climate are scarce. Our study used a multi-dimensional approach to explore the practices and perceptions of these communities and their service-providers regarding grain postharvest management in semi-arid Mbire and Hwedza districts in Zimbabwe. A total of 601 individual household interviews, six focus group discussions with women and men, and interviews with 40 district stakeholders and 53 community key informants were conducted. Farmers and service-providers explained how climate change was threatening food security; causing reduced and more variable maize and sorghum yields of below 0.5 t/ha, alongside higher grain storage insect pest pressure. Increased food insecurity and concerns regarding grain theft have driven a shift from bulk storage in traditional outdoor free-standing granaries to polypropylene bags stacked inside the living quarters. Poor and improper use of synthetic pesticides in these circumstances exacerbates the health-related risks. Agricultural extension officers were the most common source of agronomic and postharvest information followed by farmer-to-farmer information exchange. Targeted postharvest training; participatory field trials involving agricultural extension staff, farmers and other service-providers; and policy dialogue around grain postharvest management and food security are proposed to help in strengthening the capacity to reduce grain postharvest losses under increasingly unpredictable conditions.

Postharvest loss reduction throughout commodity value chains is an important pathway to food and nutrition security in sub-Saharan Africa. However, lack of understanding of the location and share of the losses and associated factors along the postharvest value chains remains a major challenge to operationalizing postharvest loss mitigation strategies. This paper assesses the determinants of postharvest losses at each postharvest stage of maize and sweetpotato (white fleshed and orange fleshed) value chains for smallholder farmers using our cross-sectional field survey data from two districts in Uganda. An ordered probit model estimation reveals that self-reported perceptions of the level of quantitative postharvest losses at different stages of commodity value chains are influenced by socio-economic factors as well as existing postharvest handling and storage practices. Increased years of education and training received on postharvest management are related to lower perceived levels of postharvest losses at key stages of value chains. Lower perceived postharvest losses are also associated with: at transport to homestead the use of sacks and bicycles as opposed to the use of baskets or transporting by trucks; at drying the use of tarpaulins as opposed to use of plastic sheets; shelling using bare-hands as opposed to beating cobs in sack with sticks; storage in a brick and mortar store as opposed to storing in living room in the house.