Browsing by Author "Millicent Kanario"

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    Influence of handling practices on pesticide residues and glycoalkaloid levels in potato (solanum tuberosum l.) tubers in Nyandarua County, Kenya
    (Egerton University, 2025) Millicent Kanario
    The safety of potato (Solanum tuberosum L.) products is of concem in Kenya due to poor handling practices along the value chain. This study determined the effect of handling practices on pesticide residues and glycoalkaloid levels in potato tubers. A cross-sectional survey of 275 farmers and 110 traders in Nyandarua County, Kenya was conducted to assess potato handling practices along the value chain using semi-structured questionnaires. Based on the handling practices, Shangi variety potato samples were collected at the farmgate (n=l6) and at the market (n=24), analysed for pesticide residues and glycoalkaloid levels respectively. Afterwards, the effect of various processing methods was determined. The separation and quantification of the target pesticides (imidacloprid, fenitrothion, chlorpyrifos, or-cypermethrin, lambda-cyhalothrin, 2,4-D, atrazine, metolachlor, glyphosate, azoxystrobin, mancozeb, metalaxyl) was done by gas chromatography-mass spectroscopy and liquid chromatography-tandem mass spectrometry system. Pesticide application rates based on agro vets‘ instructions resulted in the highest herbicide residue levels (4.63 pg/kg). Following advice from other farmers led to the highest fungicide (49.55 pg/kg) and insecticide (24.65 pg/kg) residue levels. Potatoes exposed to light had the highest levels of glycoalkaloid (834.03 mg/kg dry weight), while those with mechanical injury had the lowest levels (357.04 mg/kg dry weight). Different processing methods showed a significant difference in pesticide residue and glycoalkaloid levels in potato tubers. Frying effectively reduced most pesticide residues (92.37% to 16.41%), on-chaconine (5l.72%), and (1-solanine (41.79%), while roasting was the least effective (reducing pesticides by 73.39% to 12.46%). Steaming resulted in the lowest decrease of on-chaconine (9.13%) and 0t-solanine (6.34%). This study has shown that improper handling practices result in high pesticide residue and glycoalkaloid levels in tubers, posing a health threat to consumers. Therefore, awareness of proper handling practices is essential for consumer safety.