Bacterial species and mycotoxin contamination associated with locust bean, melon and their fermented products in south-western Nigeria

The microbiological safety of spontaneously fermented foods is not always guaranteed due to the undefined fermenting microbial consortium and processing materials. In this study, two commonly consumed traditional condiments (iru and ogiri) and their respective raw seeds (locust bean and melon) purch...

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Bibliographic Details
Published in:	International journal of food microbiology Vol. 258; pp. 73 - 80
Main Authors:	Adedeji, Bamidele S., Ezeokoli, Obinna T., Ezekiel, Chibundu N., Obadina, Adewale O., Somorin, Yinka M., Sulyok, Michael, Adeleke, Rasheed A., Warth, Benedikt, Nwangburuka, Cyril C., Omemu, Adebukola M., Oyewole, Olusola B., Krska, Rudolf
Format:	Journal Article
Language:	English
Published:	Netherlands Elsevier B.V 03-10-2017 Elsevier BV
Subjects:	3-Nitropropionic acid Acacia - chemistry Acacia - microbiology Aflatoxin B1 Alcaligenes Alcaligenes faecalis Alcaligenes faecalis - isolation & purification Animals Bacillus Bacillus - isolation & purification Bacteria Bacterial diversity Beauvericin Chromatography Citrinin Condiments Condiments - microbiology Consortia Cucurbitaceae - chemistry Cucurbitaceae - microbiology Fermentation Fermented food Fermented Foods - microbiology Flavorings Food contamination Food Safety Gene sequencing Genera Hygiene Liquid chromatography Locust beans Mass spectrometry Mass spectroscopy Melon Metabolites Microbiology Microorganisms Mycotoxins Mycotoxins - analysis Natural toxins Nigeria Ochratoxin A Processors Product safety Proteus mirabilis - isolation & purification Public health RNA, Ribosomal, 16S - genetics rRNA 16S Seeds Seeds - chemistry Seeds - microbiology Species Staphylococcus Staphylococcus - isolation & purification Sterigmatocystin Tandem Mass Spectrometry Nigeria Food safety Bacterial diversity Locust beans Natural toxins Public health Melon
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Summary:	The microbiological safety of spontaneously fermented foods is not always guaranteed due to the undefined fermenting microbial consortium and processing materials. In this study, two commonly consumed traditional condiments (iru and ogiri) and their respective raw seeds (locust bean and melon) purchased from markets in south-western Nigeria were assessed for bacterial diversity and mycotoxin contamination using 16S rRNA gene sequencing and liquid chromatography tandem mass spectrometry (LC-MS/MS), respectively. Two hundred isolates obtained from the raw seeds and condiments clustered into 10 operational taxonomic units (OTUs) and spanned 3 phyla, 10 genera, 14 species and 2 sub-species. Bacillus (25%) and Staphylococcus (23.5%) dominated other genera. Potentially pathogenic species such as Alcaligenes faecalis, Bacillus anthracis, Proteus mirabilis and Staphylococcus sciuri subsp. sciuri occurred in the samples, suggesting poor hygienic practice during production and/or handling of the condiments. A total of 48 microbial metabolites including 7 mycotoxins [3-nitropropionic acid, aflatoxin B1 (AFB1), AFB2, beauvericin, citrinin, ochratoxin A and sterigmatocystin] were quantified in the food samples. Melon and ogiri had detectable aflatoxin levels whereas locust bean and iru did not; the overall mycotoxin levels in the food samples were low. There is a need to educate processors/vendors of these condiments on good hygienic and processing practices. •Bacillus (25%) and Staphylococcus (24%) dominated in iru, ogiri and their raw seeds.•Pathogenic species of Alcaligenes, Bacillus, Proteus and Staphylococcus were found.•Seven mycotoxins were quantified in the samples; only melon and ogiri had aflatoxin.•This study reports for the first time mycotoxins in locust bean seeds and iru.
ISSN:	0168-1605 1879-3460
DOI:	10.1016/j.ijfoodmicro.2017.07.014