The high content of unsaturated fatty acids in wheat germ limits its shelf life, so the wheat germ is removed during flour production. (bakeryandsnacks.com)
Some nutritionists theorize that the high level of unsaturated fatty acids in fish lend themselves to the formation of free radical groups upon spoiling. (2ndchance.info)
Zhang, D., et al. «Ginseng extract scavenges hydroxyl radical and protects unsaturated fatty acids from decomposition caused by iron mediated lipid peroxidation,» Free Radical Biol in Med, 20 (1): 145 - 50, 1996. (chiro.org)