Diversity and selected functional traits of microbiota associated with traditional dried plant foods from South African informal markets

Abstract

Abstract Traditional plant-based products provide nutritional benefits and support cultural heritage; however, their sale in urban informal markets raises potential food safety considerations. We characterized the microbiota of five traditional dried plant products (baobab, masau, nyii, dinawa, and lude) obtained from three informal markets in South Africa (n = 51 samples) using 16S rRNA gene sequencing and quantitative real-time PCR; selected isolates (n = 87) were further evaluated using selected phenotypic assays. Bacterial abundance and composition varied across products and vendors. Baobab exhibited the highest microbial richness (1,460 ASVs) but relatively low bacterial loads (106 16S rRNA gene copies g−1), whereas dried leafy greens showed the lowest richness (470 ASVs) but the highest bacterial abundance (109 copies g−1). Across products, higher bacterial diversity correlated with genera such as Bifidobacterium and Prevotella, while higher bacterial abundance correlated with genera such as Salmonella, Vibrio, and Acinetobacter. Notably, health implications of detected taxa cannot be inferred from genus-level identification based on 16S rRNA gene sequencing. Phenotypic traits observed among selected isolates included growth in the presence of several antibiotics (particularly sulfadiazine and ampicillin), protease activity, and inhibition of indicator strains under laboratory conditions. Overall, traditional dried plant foods harbor diverse microbial communities shaped by plant characteristics and vendor-related practices, highlighting the importance of improved handling and drying practices.