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Ademola OM, Adeyemi TE, Ezeokoli OT, Ayeni KI, Obadina AO, Somorin YM, Omemu AM, Adeleke RA, Nwangburuka CC, Oluwafemi F, Oyewole OB, Ezekiel CN. Phylogenetic analyses of bacteria associated with the processing of iru and ogiri condiments. Lett Appl Microbiol 2018; 67:354-362. [PMID: 29947432 DOI: 10.1111/lam.13040] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Revised: 05/26/2018] [Accepted: 06/22/2018] [Indexed: 01/29/2023]
Abstract
Analysis of the bacterial community dynamics during the production of traditional fermented condiments is important for food safety assessment, quality control and development of starter culture technology. In this study, bacteria isolated during the processing of iru and ogiri, two commonly consumed condiments in Nigeria, were characterized based on phylogenetic analyses of the bacterial 16S rRNA gene. A total of 227 isolates were obtained and clustered into 12 operational taxonomic units (OTUs) based on 97% 16S rRNA gene similarity. The OTUs spanned three phyla (Firmicutes, Actinobacteria and Proteobacteria), and nine genera: Acinetobacter, Aerococcus, Bacillus, Enterococcus, Enterobacter, Lysinibacillus, Micrococcus, Proteus and Staphylococcus. OTUs closely related to species of Bacillus dominated the processing stages of both condiments. Although no single OTU occurred throughout iru processing stages, an OTU (mostly related to B. safensis) dominated the ogiri processing stages indicating potentials for the development of starter culture. However, other isolates such as those of Enterococcus spp. and Lysinibacillus spp. may be potential starters for iru fermentation. Presumptive food-borne pathogens were also detected at some stages of the condiments' processing, possibly due to poor hygienic practices. SIGNIFICANCE AND IMPACT OF THE STUDY Iru and ogiri are important condiments used for flavour enhancement in foods and serve as protein substitutes in diets among rural populations across West Africa. Consumption of these condiments is growing, reinforcing the need to scale up their production. Production of these condiments includes spontaneous fermentation, which often leads to inconsistent product quality and unguaranteed safety. This study has demonstrated the bacterial succession in iru and ogiri processing and highlights species that could be selected and exploited for starter culture development. This study provides a starting point to produce quality and microbiologically safe iru and ogiri condiments.
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Affiliation(s)
- O M Ademola
- Department of Food Science and Technology, Federal University of Agriculture, Abeokuta, Nigeria
| | - T E Adeyemi
- Department of Microbiology, Federal University of Agriculture, Abeokuta, Nigeria
| | - O T Ezeokoli
- Microbiology and Environmental Biotechnology Research Group, Agricultural Research Council-Institute for Soil, Climate and Water, Arcadia, South Africa.,Unit for Environmental Science and Management, North-West University (Potchefstroom Campus), Potchefstroom, South Africa
| | - K I Ayeni
- Department of Microbiology, School of Science and Technology, Babcock University, Ilishan Remo, Nigeria
| | - A O Obadina
- Department of Food Science and Technology, Federal University of Agriculture, Abeokuta, Nigeria
| | - Y M Somorin
- Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - A M Omemu
- Department of Hospitality and Tourism Management, Federal University of Agriculture, Abeokuta, Nigeria
| | - R A Adeleke
- Microbiology and Environmental Biotechnology Research Group, Agricultural Research Council-Institute for Soil, Climate and Water, Arcadia, South Africa.,Unit for Environmental Science and Management, North-West University (Potchefstroom Campus), Potchefstroom, South Africa
| | - C C Nwangburuka
- Department of Agriculture, School of Science and Technology, Babcock University, Ilishan Remo, Nigeria
| | - F Oluwafemi
- Department of Microbiology, Federal University of Agriculture, Abeokuta, Nigeria
| | - O B Oyewole
- Department of Food Science and Technology, Federal University of Agriculture, Abeokuta, Nigeria
| | - C N Ezekiel
- Department of Microbiology, School of Science and Technology, Babcock University, Ilishan Remo, Nigeria
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Ezekiel CN, Sulyok M, Frisvad JC, Somorin YM, Warth B, Houbraken J, Samson RA, Krska R, Odebode AC. Fungal and mycotoxin assessment of dried edible mushroom in Nigeria. Int J Food Microbiol 2013; 162:231-6. [PMID: 23454813 DOI: 10.1016/j.ijfoodmicro.2013.01.025] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 01/11/2013] [Accepted: 01/21/2013] [Indexed: 11/28/2022]
Abstract
In order to determine whether dried mushrooms are a foodstuff that may be less susceptible to infection by toxigenic molds and consequently to mycotoxin contamination, 34 dried market samples were analyzed. Fungal population was determined in the samples by conventional mycological techniques and molecular studies, while the spectrum of microbial metabolites including mycotoxins was analyzed by a liquid chromatography tandem mass spectrometric method covering 320 metabolites. Molds such as Fusarium, Penicillium, Trichoderma and aflatoxigenic species of Aspergillus (Aspergillus flavus and Aspergillus parvisclerotigenus) were recovered from all samples at varying levels. None of the mycotoxins addressed by regulatory limits in the EU was positively identified in the samples. However, 26 other fungal metabolites occurred at sub- to medium μg/kg levels in the samples, including aflatoxin/sterigmatocystin bio-precursors, bis-anthraquinone derivatives from Talaromyces islandicus, emerging toxins (e.g. enniatins) and other Fusarium metabolites, and clavine alkaloids. Although little is known on the toxicology of these substances, the absence of aflatoxins and other primary mycotoxins suggests that dried mushrooms may represent a relatively safe type of food in view of mycotoxin contamination.
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Affiliation(s)
- C N Ezekiel
- Mycology/Mycotoxicology Research Unit, Department of Biosciences and Biotechnology, Babcock University, Ilishan Remo, Ogun State, Nigeria.
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