Assessing The Impact of Climate Change and Ripening-Delaying Chemicals on Fruit Safety, Quality, And Human Health in Kenya

Escalating climate variability across sub-Saharan Africa is reshaping horticultural systems, accelerating postharvest losses and driving greater reliance on ripening-modifying chemicals as an adaptive strategy. This study investigated how climate stress drives the use of ripening-accelerating and ripening-delaying chemicals in fruits sold in Kenyan markets, and how this growing dependence creates food safety and public health risks. A mixed-methods design combined field surveys (n = 180), laboratory analysis of 392 fruit samples using gas chromatography–mass spectrometry, and multivariate statistical modelling across Meru, Nairobi, Murang’a, and Kirinyaga counties between September 2024 and April 2025. The results showed that 63% of respondents used chemical ripening agents, with calcium carbide (42%) and ethephon (27%) being the most common. Residue analysis detected contaminants in 26% of the samples, while modeled acetylene concentrations in carbide-treated fruits exceeded the 0.7 mg/kg reference threshold. Regression analysis showed that rainfall variability (β = 0.41, p < .01) and market pressure (β = 0.36, p < .05) significantly predicted chemical use, while farmer knowledge and regulatory enforcement attenuated these relationships. Calcium carbide use increased modeled public health risk (β = 0.67), whereas regulatory enforcement reduced risk (β = -0.45). These findings reveal governance gaps, low risk awareness, and an urgent need for safer postharvest technologies, integrated monitoring, and climate-resilient storage systems.