Evaluation of the microbiological quality of spices sold in open markets in Senegal by looking for all the bacterial species that can proliferate there
Natural spices are reputed to play an important role in human nutrition and well-being, due to their organoleptic and therapeutic properties. Moreover, these natural products are increasingly being processed on various scales, exposing them to potential sources of contamination. The aim of this study was to describe the bacterial community in spices sold in Senegal.  Samples were collected in selected open markets in Dakar and Saint-Louis, Senegal. The samples were Thyme, Curcuma, Mixture of 7 spices and local spices or herbs. DNA extraction were performed using the Omega E.N.Z.A Food DNA kit (Omega Bio-Tek, GA, USA) following manufacturer protocols. PCR tests were based on genomic fragment coding for bacterial 16S rRNA. The amplicons were then purified using the ZYMO RESEARCH DNA Clean & Concentrator kit (Zymo Research, Irvine, CA, USA). The targeted genomic region was sequenced using the Oxford Nanopore Technology (ONT) MinIon Mk1C sequencer. Sequencing was carried out on 2 batches of samples containing 10 «local spices or herbs” s (blend of food seasonings) and 39 (blend of 7 spices, curcuma, thyme and local spices or herbs). Sequencing data analysis allowed to identify high bacterial diversity and he predominance of Escherichia coli, Salmonella enterica, Escherichia marmotae, Synechococcus sp. JA-3-3Ab, Brevundimonas sp. Bb-A, Pseudanabaena sp. PCC 7367 and Klebsiella pneomoniae in samples with a total number of reads of 65744 and 165325 for the two batches respectively.  «local spices or herbs” s represented the sample category with the highest diversity. They were followed by curcuma, 7-spice blend and thyme respectively. These results highlight a wide diversified the genomic profile of microbial community which include pathogenic bacteria in spices samples. Additional investigations using cultural approach will allow to determine the levels of contamination and therefore qualify these matrices suitable or not for human consumption.