I recall reading, perhaps 20 years ago, of a case in Japan where a man showed drunkeness/detectable-blood-alcohol without drinking alcoholic beverages. In that popular account, it was attributed to an intestinal strain of <i>e coli</i> creating alcohol, and a genetic difference (more common in Asia and among Native Americans) that interferes with alcohol-breakdown.<p>Yeast seems even more likely a culprit, and I see the references in this case study detail Japanese cases/research back to the 1970s.<p>This newest case study does not mention the 61-year-old male's race... but if of Asian or Native American descent, or maybe even if not, they should have also checked his genetically-influenced ability to metabolize alcohol.