Metagenomic tracking of microbial consortia of cassava flakes (garri)

Abstract

The affirmation of several cross-sectional studies on the vulnerability of cassava flakes commonly called 'garri' to microbial attack has long been documented. However, longitudinal data on metagenomic tracking of microbial consortia of this important staple food are scarce. Hence, this study was aimed at tracking the microbial consortia of garri. A total of eight samples (four each from both Nigeria and Republic of Benin markets) were randomly collected aseptically using pre-sterilized aluminum pans and processed through a metagenomic approach, while both the chemical and proximate components of garri were assessed following standard techniques. The analysis of the taxonomic consortia of garri reveals the predomination of bacteria (99.82 and 99.81% for samples from Nigeria and Republic of Benin, respectively) while the remaining sequences matched with the Archae (0.07%), fungi (0.09%) and protozoa (0.09%). A large proportion of the sequences were unclassified at the phylum level (approximately 84.10 and 86.2% for Nigerian and Beninese samples, respectively). The reads of cassava flakes metagenome of both Nigeria and Republic of Benin exhibited analogous level of average GC content with sequence count of between 187773-213444 for samples from Nigeria and 157784-198763 for samples from Republic of Benin. The functional characteristics of the inhabiting metagenomes were found containing the genes encoding for adhesins, bacteriocins, resistance to antibiotics, toxic chemicals as well as toxins and superantigens. Both the chemical and the proximate compositions of the examined garri samples, though exhibited significant disparity, but without any apparent variation in the patterns of metagenomic data. Our findings however revealed bacteria as the major contaminants of these cassava food products.

Keywords; Metagenomics, Microorganisms, Cassava flakes (garri), Proximate composition