Koji mold, natural and engineered (IMAGE) DOE/Lawrence Berkeley National Laboratory Caption The petri dish on the left contains the natural koji mold, whereas the one on the right has been engineered to contain higher levels of a nutrient called ergothioneine and more heme – an iron-based molecule found in many organisms, but is especially abundant in animal tissues, which gives meat a distinctive flavor. Credit Marilyn Sargent/Berkeley Lab Usage Restrictions Use credit License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.