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Rodents are one of the major storage pests in on-farm maize storage in the tropics. However, information on actual magnitude of weight and quality losses caused by rodents in maize stores and species of rodent associated with the losses is scarce and if available would help to improve maize postharvest management. Maize stores of small-scale farmers in the lowland tropical zone of Kenya were monitored for actual weight losses caused by rodents and rodent trapping was conducted to determine species and estimate population of the rodents associated with the losses. Moulds and total aflatoxin contamination and nutritional value of rodent-damaged grain and non-damaged grain samples were also compared to evaluate the impact of rodent infestation on grain quality. In a sample of 20 farmers, we found that cumulative weight losses due to rodents ranged from 2.2 to 6.9% in shelled maize grain and from 5.2 to 18.3% in dehusked cobs after storage for 3 months. Rattus rattuswas the only rodent species captured over the whole trapping period with a trap success rate of 0.6–10.0%. Total mould count, Fusariumspp. incidence and total aflatoxin contamination were significantly higher in rodent-damaged grains than in the non-damaged ones whereas no significant differences were observed for the incidence of Aspergillusspp. There were also significant decreases in dry-matter, fat, crude protein and fatty acid content in rodent-damaged grain compared to non-damaged grain. These findings show that rodents are a significant cause of postharvest losses in on-farm maize storage and impact negatively on food nutrition and safety. Mitigation strategies for postharvest losses should therefore include rodent control.

Rodents are one of the major postharvest pests that affect food security by impacting on both food availability and safety. However, knowledge of the impact of rodents in on-farm maize storage systems in Kenya is limited. A survey was conducted in 2014 to assess magnitudes of postharvest losses in on-farm maize storage systems in Kenya, and the contribution of rodents to the losses. A total of 630 farmers spread across six maize growing agro-ecological zones (AEZs) were interviewed. Insects, rodents and moulds were the main storage problems reported by farmers. Storage losses were highest in the moist transitional and moist mid-altitude zones, and lowest in the dry-transitional zone. Overall, rodents represented the second most important cause of storage losses after insects, and were ranked as the main storage problem in the lowland tropical zone, while insects were the main storage problem in the other AEZs. Where maize was stored on cobs, total farmer perceived (farmer estimation) storage weight losses were 11.1 ± 0.7 %, with rodents causing up to 43 % of these losses. Contrastingly, where maize was stored as shelled grain, the losses were 15.5 ± 0.6 % with rodents accounting for up to 30 %. Regression analysis showed that rodents contributed significantly to total storage losses (p< 0.0001), and identified rodent trapping as the main storage practice that significantly (p= 0.001) lowered the losses. Together with insecticides, rodent traps were found to significantly decrease total losses. Improved awareness and application of these practices could mitigate losses in on farm-stored maize.

The study was conducted to determine the efficacy of two 1–MCP application regimes (2 ppm for 24 hours and 4 ppm for 12 hours) to extend the shelf life of passion fruits. The fruits were harvested at two stages of maturity (stage 1 and 2) based on peel colour. After 1–MCP treatments, the fruits were kept at ambient room conditions (25 ± 1°C and RH 60 ± 5%) to ripen. Physiological and physicochemical changes associated with fruit ripening, including ethylene evolution, respiration rate, weight loss, peel colour, total soluble solids and total titratable acidity were evaluated every 2 or 3 days from six fruits which were randomly sampled from each of the treatment combinations. 1–MCP treatments significantly (p < 0.05) delayed or reduced the rate of most of the ripening changes irrespective of the harvest maturity. Overall, based on the physiological and physicochemical changes observed, 1–MCP treatments prolonged the postharvest shelf life of passion fruits harvested at stage 1 and 2 by 3 and 4 days respectively.

Papaya is a thin-skinned fruit that ripens and softens over a very short time, usually in 3 days, predisposing the fruit to physical damage and phyto-pathogen invasion even with careful handling further shortening postharvest shelf life. The objective of this study was to determine the efficacy of Hexanal, naturally occurring compound, on-farm spray, in managing the postharvest shelf life of papaya in two agro-ecological zones in Kenya. A formulation of Hexanal containing Tween 20 and ethanol was made by volume basis (v/v) and spray treatment at 1 and 2% in “Solo sunrise” and “Mountain” papaya cultivars. The experiment was a randomized block design with ninety-six plants per farm randomly selected. Spraying was applied at 30 days, 30 + 15 days, and 15 days to harvest time on mature green papaya. Control papaya fruits were sprayed with clean tap water as control. Data were collected on color changes and fruit retention on tree. The fruits were harvested when two to three yellow stripes were visible from the lower end of the fruits for postharvest analysis. Hexanal sprayed papaya fruits were retained for at least 13 days longer compared to the control fruits on tree. Hexanal treatment at 2% revealed an improved effect on managing papaya postharvest shelf life. All fruits treated with Hexanal significantly showed reduced rate of color break, softening, and enhanced extension of fruit shelf life by at least 6 days. Hexanal treatment also delayed ethylene and respiratory peaks by three days and showed no significant (P≤0.05) difference in the levels of total titratable acidity and total soluble solids. The results of this study indicate that Hexanal applied as a preharvest spray on mature green “Solo sunrise” and “Mountain” papaya cultivars grown in Kenya, is effective in prolonging shelf life and postharvest quality.

An on-farm study was conducted among smallholder mango farmers in Embu County of Kenya to demonstrate the effectiveness of simple harvest and postharvest handling practices to attain cold chain and extend mango shelf life. The recommended cold chain practices were compared with common farmers' practices. 'Apple', 'Ngowe', 'Kent', and 'Tommy Atkins' harvested at the mature green stage were used in the study. To demonstrate proper cold chain, fruits were harvested before 8 am, transported in crates lined with dampened newspapers, precooled in an evaporative charcoal cooler, and then transferred to a Coolbot™ cold room (10 ± 2°C). To demonstrate common farmers’ practices, fruits were harvested at noon, transported in open crates, and stored at ambient room conditions (25 ± 7°C, 55 ± 15%RH). The air and fruit pulp temperatures were monitored regularly using HUATO® data loggers. During the storage period, a random sample of 3 fruits (per variety) per treatment was taken after every 3 days to evaluate ripening related changes including physiological weight loss, colour, firmness, and total soluble solids. Proper cold chain practices resulted in low fruit pulp temperature (average 11°C) compared to 25°C for fruits handled using common practices by farmers leading to faster ripening as evidenced by lower peel/pulp colour and firmness, higher physiological weight loss, and higher total soluble solids. For example, flesh firmness of fruits under poor cold chain practices decreased from initial 36.6 N, 45.9 N, 66.5 N, and 46.8 N to 3.1 N, 2.4 N, 3.2 N, and 3.1 N for ‘Apple’, ‘Ngowe’, ‘Kent’, and ‘Tommy Atkins’ varieties, respectively, at the end of storage while that of fruits under proper cold chain practices reduced to 2.3 N, 1.5 N, 3.9 N, and 2.9 N, respectively, for the four varieties at the end of storage. Overall, proper cold chain management extended mango shelf life by 18 days. Application of simple harvest and handling practices coupled with simple storage technologies can attain and maintain the cold chain required to preserve quality and extend shelf life. This could increase the marketing and storage periods for later selling and processing, respectively, of mango fruits.