Session: General Poster:

Doenjang is known as a traditional fermented soybean-based food in Korea, but safety concerns have been raised as it can be contaminated with fungi that produce aflatoxin (AF) and/or ochratoxin A (OTA) during the fermentation process. To address this, the modified method of adding selected microorganisms to starter (meju) or soybean, is sometimes used in homes and factories. The purpose of this study is to optimize and validate the method of analyzing AF and OTA in doenjang matrix, and to compare the levels of AF and OTA in home-style and commercial doenjangs prepared with traditional and modified methods. The optimized method was validated in terms of linearity (R²≥0.9999), limit of detection (0.015-0.173 μg/kg), limit of quantification (0.047-0.526 μg/kg), recovery (intra-day: 84.5-98.3%, inter-day: 84.0-100.0%), and precision (intra-day: 2.72-6.25%, inter-day: 2.93-7.44%). Using the method, we analyzed AF and OTA levels of a total of 60 (15 each) home-style and commercial doenjang samples prepared with traditional and modified methods. AF and OTA were detected in 11 out of 30 home-style doenjangs and in 7 out of 30 commercial doenjangs. All mycotoxins (AFB1, AFB2, AFG1 and OTA) except AFG2 were detected in doengang prepared with traditional method, but only trace amounts of AFB1 were detected in doenjang prepared with modified method. In the commercially available traditional and modified doenjangs, total AF (sum of AFB1, AFB2, AFG1 and AFG2) was in the range of 0.54-37.89 μg/kg and 0.18-0.39 μg/kg, respectively. On the other hand, in homemade traditional and modified doenjangs, total AF was 1.72-281.92 μg/kg and 0.23 μg/kg, respectively. OTA was in the range of 1.25-32.64 μg/kg in traditional doenjang, but was not detected in modified doenjang. These findings suggest that the AF and OTA levels of modified doenjang are lower than those of traditionally prepared doenjang.

Mr Seung Yoon Kang

Comparison of aflatoxin and ochratoxin A levels in home-style and commercial doenjangs (soybean paste) prepared with traditional and modified methods, Chung-Ang University

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