Aflatoxin Reduction and Retardation of Aflatoxin Production by Microorganisms in Doenjang during a One-Year
Vishal Kumar1, Ashutosh Bahuguna1, Srinivasan Ramalingam1
1Department of Food Science and Technology, Yeungnam University, Gyeongsan 38541, Gyeongsangbuk-do, Korea.
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.
Insights
A year of doenjang fermentation significantly reduced aflatoxins by over 97%, primarily during the meju stage. Native microorganisms in doenjang effectively degrade aflatoxins, suggesting their use as starter cultures for safer products.
Area of Science:
- Food Science
- Microbiology
- Mycotoxicology
Background:
- Meju, a key ingredient in doenjang, is susceptible to aflatoxin contamination from fungi like Aspergillus flavus.
- Aflatoxins pose a significant health risk, necessitating strategies for their reduction in fermented foods.
Purpose of the Study:
- To assess the impact of one-year doenjang fermentation on reducing aflatoxins (B1, G1, B2, G2) and toxigenic Aspergillus flavus.
- To identify microorganisms responsible for aflatoxin degradation during doenjang fermentation.
Main Methods:
- Doenjang was prepared with spiked aflatoxins and inoculated with Aspergillus flavus.
- Samples were fermented for one year, with aflatoxin levels and microbial populations analyzed periodically.
- Aflatoxin-degrading fungi and bacteria were isolated and identified.
Main Results:
- A significant reduction in aflatoxins was observed after one year: 92.58% (B1), 100% (G1), 98.69% (B2), and 100% (G2).
- Total aflatoxin levels decreased by 97.88%, from 328.83 µg/kg to 6.95 µg/kg.
- Native fungi (Aspergillus versicolor, Cladosporium subcinereum, Aspergillus ochraceus) and bacteria (Bacillus albus, Bacillus velezensis) were identified as key aflatoxin degraders.
Conclusions:
- Native microorganisms in doenjang play a crucial role in mediating aflatoxin reduction during fermentation.
- The meju stage is the most vulnerable period for aflatoxin contamination and Aspergillus flavus growth.
- Utilizing these identified microorganisms as starter cultures could lead to the production of aflatoxin-free doenjang.
More Related Videos
09:44RNAi-mediated Control of Aflatoxins in Peanut: Method to Analyze Mycotoxin Production and Transgene Expression in the Peanut/Aspergillus Pathosystem
Published on: December 21, 2015
10:01Quantification of Fungal Colonization, Sporogenesis, and Production of Mycotoxins Using Kernel Bioassays
Published on: April 23, 2012
Related Concept Videos
01:27Microorganisms in Agriculture and Food industry
01:29Fermentation
Fermentation is a type of metabolic process that occurs in the absence of oxygen, where organic molecules such as glucose are broken down to produce energy. During this process, the...
01:23Microbial Fermentation