Aflatoxin Reduction and Retardation of Aflatoxin Production by Microorganisms in Doenjang during a One-Year Fermentation

Abstract

Meju, a raw material for doenjang preparation, is highly vulnerable to aflatoxin-producing fungi. The aim of this study was to evaluate the effect of a one-year fermentation on aflatoxins and aflatoxin-producing fungi in doenjang spiked with aflatoxins B1, G1, B2, and G2 and inoculated with toxigenic Aspergillus flavus. A significant reduction in aflatoxins was observed after a year of fermentation, measuring 92.58%, 100%, 98.69%, and 100% of B1, G1, B2, and G2, respectively. After a year of fermentation, 6.95 ± 3.64 µg/kg of total aflatoxin was detected, which represents a 97.88% reduction in the total aflatoxin compared with the initial value (328.83 ± 36.60 µg/kg). Several aflatoxin-degrading fungi (Aspergillus versicolor, Cladosporium subcinereum, Aspergillus ochraceus) and bacteria (Bacillus albus, Bacillus velezensis) isolated from doenjang were identified as the major contributors to the reduction of aflatoxin. Furthermore, it was observed that most of the aflatoxin contamination in doenjang occurred during the meju stage, and this stage was found to be most susceptible to A. flavus contamination and growth. These findings reveal that native microorganisms mediate aflatoxin clean-up in doenjang during fermentation and support the use of such microorganisms as a starter culture for the preparation of aflatoxin-free doenjang.

Nutritional interventions to prevent inflammatory diseases linked to exposure to environmental toxins in food

“…Even though this commentary focuses on persistent environmental pollutants as a source of environmental toxins in foodstuffs, mycotoxins in contaminated foods can also contribute to serious health hazards in mammals (Kumar, et al, 2022a; Kumar et al, 2022b). Mycotoxins are secondary metabolites produced by fungi, for example, Aspergillus , Fusarium , Neurospora , Penicillium , and so on, mostly during milling and preparation of grain and grain products and during transportation and storage of these food products.…”

Differential Expression of Genes Related to Growth and Aflatoxin Synthesis in Aspergillus flavus When Inhibited by Bacillus velezensis Strain B2

“…Aflatoxins belong to a class of secondary metabolites of A. flavus and include varieties and the four major types are B1, B2, G1 and G2. Aflatoxin B1 (AFB1) exerts strong mutagenicity and carcinogenicity [ 6 ], which is classified as a Group 1 human carcinogen by the International Agency for Research on Cancer [ 7 , 8 ]. It is converted to AFB1-8 and 9-epoxide in the liver, catalyzed by cytochrome P450 associated enzymes after being ingested by animals, forming adducts with the guanine base of DNA, thus resulting in acute and chronic diseases called aflatoxicoses in both human and household animals feeding high levels of aflatoxins-contaminated food [ 9 ].…”

Visual detection of aflatoxin B1 and zearalenone via activating a new catalytic reaction of “naked” DNAzyme

“…AFs are difuranocoumarin derivatives with four major members including aatoxin B1, B2, G1 and G2 (AFB1, AFB2, AFG1 and AFG2). 5 Of the known AFs, AFB1 with high toxic potency and occurrence has been well-characterized and shown to lead to the development of hepatocellular carcinoma in humans and animals. 6,7 The toxicity of AFB1 is 10 times that of potassium cyanide and 68 times that of arsenic, showing considerable threats to public health safety.…”