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Evaluation of fungal microflora for aflatoxin producing possibility in novel quality Meju fermented with single and/or multiple additions of Nelumbo nucifera, Ginkgo biloba, and Allium sativum extracts

Shukla, Shruti, Park, Juyeon, Park, Jung Hyun, Kim, Min Kyeong, Park, Sangje, Dubey, Akanksha, Jeon, Junhyun, Khang, Yongho, Kim, Myunghee
Journal of food safety 2017 v.37 no.4
Agaricaceae, Allium sativum, Aspergillus, DNA, Eurotium, Ginkgo biloba, Mucor, Nelumbo nucifera, Paecilomyces, Penicillium chrysogenum, aflatoxin B1, fermentation, fermented foods, fungi, garlic, leaves, medicinal plants, nucleotide sequences, ochratoxins, pathogens, plant extracts, sequence analysis, starter cultures, Korean Peninsula
This study was aimed to evaluate the fungal microflora in Meju samples fermented using single and/or multiple additions of ethanolic extracts from plants, including Nelumbo nucifera leaves, Ginkgo biloba leaves, and Allium sativum cloves, at different concentrations (1 and 10%) and mixtures of these extracts at a 1:1:1 ratio. Fungal species were grouped based on morphological characteristics, and selected fungal strains were identified based on DNA sequence analysis. Aspergillus species were the dominant microflora in Meju samples. A total of 10 fungal strains isolated from the tested Meju products resulted in the identification of five genera, including Agaricaceae, Aspergillus (synonym: Eurotium), Mucor, Penicillium, and Paecilomyces. Further, Meju samples fermented with selected individual and/or multiple ethanolic extracts resulted in the occurence of various fungal strains, including Aspergillus, Mucor, Paecilomyces, and Penicillium chrysogenum. Conversely, Meju samples fermented without ethanolic extracts as a control resulted in the isolation of Aspergillus ruber, which might be capable of producing aflatoxin B1 and ochratoxin A. The outcome of this study confirms that fermentation of Meju using plant extracts may significantly influence fungal microflora, leading to improved quality of Meju production, because of diminishing effects of the extracts against toxin producing fungal pathogens. PRACTICAL APPLICATIONS: For decades, fermented foods have been used traditionally as health beneficial products in Asian countries including Korea. Contamination of fermented food starter culture, such as soybean‐based Meju, by pathogenic fungi or toxin producing fungi, such as Aspergillus species, has been reported as a severe concern to consumers. Medicinal plants have shown remarkable efficacy to control a number of pathogenic microbes including fungi. In this study, Nelumbo nucifera leaves, Ginkgo biloba leaves, and Allium sativum cloves exhibited significant potential to diminish the growth of toxin producing fungi, suggesting potential application of medicinal plants for the improved quality of Meju production.