Doenjang has had to endure a rather negative reputation because it has been linked to
stomach cancer in Korea. A positive association between doenjang intake and stomach
cancer was first reported by Crane et al.64 in 1970. In this case-control study, the
authors simply speculated that the causal factor might be contamination by aflatoxin.
However, this mycotoxin is presently considered as a liver but not a stomach carcinogen.
The main reason for the speculation was that one of the main fungi involved
in the fermentation of meju is Aspergillus oryzae, which is in the same genus as the
aflatoxin-producing A. flavus. However, the production of the toxin during and after
Handbook of Fermented Functional Foods, Second Edition
natural fermentation of meju was found to be insignificant, even though A. flavus
could grow quite well.