Abstract:
Purpose: Ready-to-eat fast food vending outlets provide a cheap and readily available food. Foodborne diseases
have been previously reported in Embu, Kenya, but data on the prokaryotic metagenome in vended foods is
scanty. This study aimed to determine the prokaryotic diversity in fruits, vegetable salad, African sausage, chips
(potato fries), fried fish, roasted beef (meat), smokies, samosa, soil, and water collected from food vendors and the
surrounding environment in Embu Town and Kangaru Market.
Methods: The study used 454 pyrosequencing, Illumina high-throughput sequencing of 16S rRNA gene in the
analysis of total community DNA extracted from samples using the phenol-chloroform method. The 16S rRNA gene
variable region (V4-V7) of the extracted DNA was amplified and library construction performed. Sequence analysis
was done using QIIME2. Hierarchical clustering of samples, diversity indices, rarefaction curves, and Venn diagrams
were generated using the R programming language in R software version 3.6.3.
Results: Bacterial operational taxonomic units (OUTs) were distributed in Proteobacteria (52.81%), Firmicutes
(31.16%), and Lentisphaerae (0.001%). The OTUs among archaea were Candidatus Nitrososphaera (63.56%) and
Nitrososphaera spp. (8.77%). Brucella spp. and Bacillus cereus associated with foodborne diseases were detected.
Potential pathogens, Rickettsia spp. in risk group 2 and Brucella spp. in risk group 3, were detected. Uncultured
Candidatus Koribacter and Candidatus Solibacter were also detected in the food samples. There was a significant
difference in the microbial community structure among the sample types (P<0.1).
Conclusion: The results demonstrated the presence of some prokaryotes that are associated with food spoilage or
foodborne diseases in vended foods and environmental samples. This study also detected uncultured prokaryotes.
The presence of potential pathogens calls for stringent hygiene measures in food vending operations.
