Analysis of Groundnuts Sold by Street Vendors in Gaborone for Hygiene and Aflatoxin Content
Abstract
Background: Street-vended foods are integral to urban food systems in developing countries, yet pose significant public health risks due to inadequate hygiene practices and contamination hazards. This study assessed the microbiological quality and aflatoxin contamination of ready-to-eat groundnuts sold by street vendors in Gaborone, Botswana. Methods: A cross-sectional study was conducted among 37 street vendors operating in three commercial hubs of Gaborone between March and May 2019. Vendors were surveyed using structured questionnaires, and composite groundnut samples (one per vendor) were collected for laboratory analysis. Hygiene status was evaluated through enumeration of Escherichia coli using serial dilution and plating on selective agar. Aflatoxin concentrations (B1, B2, G1, G2) were quantified using Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) following immunoaffinity column clean-up. Results: All 37 composite samples (100%) exhibited unacceptable microbiological contamination, with E. coli counts ranging from 2.0 × 10⁵ to 1.86 × 10⁶ CFU/g (mean 8.42 × 10⁵ ± 4.95 × 10⁵ CFU/g), substantially exceeding the guideline threshold of <1 × 10² CFU/g for ready-to-eat foods. Aflatoxin analysis revealed severe contamination, with 94.6% (35/37) of samples exceeding Botswana's regulatory limit of 10 µg/kg for total aflatoxins. Total aflatoxin concentrations ranged from below the detection limit to 1966.72 µg/kg, with aflatoxin B1 as the predominant congener. Key contributing factors identified included lack of vendor licensing (97.3%), sourcing from Zambia (81.1%), inadequate storage in non-breathable containers (59.5%), and absence of personal protective equipment (70.3%). Conclusion: Street-vended groundnuts in Gaborone present a dual public health threat from biological and chemical contamination. The findings underscore systemic failures in food safety governance within the informal sector and suggest the need for integrated interventions spanning regulation, vendor education, infrastructure improvement, and supply chain management.