Dr. Ajit Varki of the University of California-San Diego School of Medicine, says the bacterium targets a non-human molecule absorbed into the body through red meats such as lamb, pork and beef.
The scientists discovered that a potent bacterial toxin called subtilase cytotoxin specifically targets human cells that have a non-human, cellular molecule on their surface. The molecule -- N-glycolylneuraminic acid, or Neu5Gc -- is a type of glycan, or sugar molecule, that humans don't naturally produce.
Subtilase cytotoxin is produced by certain kinds of E. coli bacteria, causing bloody diarrhea and a potentially fatal disease called haemolytic uraemic syndrome in humans, Varki says.
"When the toxin binds to the non-human Neu5Gc receptors, it can result in serious food-poisoning and other symptoms in humans," Varki says in a statement.
The research emphasizes the need for people to eat only well-cook meat or pasteurized dairy products -- processes that destroy contaminating bacteria, Varki says.
The findings are published online ahead of print in the journal Nature.