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The changes of aflatoxins of traditional Korean soy sauce (kan-jang) and soybean paste (doen-jang) during ripening and storage for 12 months and the characteristics of the changes were investigated. All of the preparation methods for meju cakes (soybean cakes), soy sauce, and soybean paste followed the recommendations of the Korea Food Research Institute. Focal components and aflatoxins were analyzed at 0, 3, 6, 9, and 12 months. At the initial stage aflatoxins were detected at a trace level (below the detection limit, 2 ppb), 7.2 ppb, 2.8 ppb, and 3.9 ppb in soybeans, meju cakes, soy sauce and soybean paste, respectively. We suspect that the process of making and fermenting meju cakes was mainly responsible for- the aflatoxin contamination in the soy sauce and soybean paste. Parts of the toxins in the soybean paste were degraded during ripening and storage and showed only a trace level in 6 months. Although the aflatoxin content of soy sauce increased over 1 year of storage time, it was still far below the 10 ppb safety limit of the Standards and Specifications of Korea; furthermore we could expect destruction of parts of toxin in the soy sauce when we boil it in cooking. It was strongly suspected that these changes in the soy sauce and soybean paste were due to the difference in their crude fat and fatty acid content. This study indicates that soy sauce and soybean paste are quite safe to eat; although more research should be conducted to discover how to eliminate even the Flow levels of aflatoxin found especially in the soy sauce.
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