Now humans don't make Neu5Gc, but they consume foods that have high levels of the sugar in question. Red meat and dairy products are particularly rich in Neu5Gc. Hence consumption of such food items makes one susceptible to attack by the toxin, it is theorized.
An international team of researchers studied E.coli, and their findings are published in the journal Nature.
"Red meat and dairy products, the richest dietary sources of Neu5Gc, are also the foods that are most commonly contaminated with the E. coli
bacteria that produce the toxin," says Dr Adrienne Paton, a microbiologist of the University of Adelaide and a co-author of the paper.
"Through dietary choices, therefore, humans may expose themselves to an increased risk of infection with the E. coli
bacteria and simultaneously sensitise themselves to the potentially lethal actions of the toxin it produces," Paton points out.
E.coli cause bloody diarrhoea and haemolytic uraemic syndrome (HUS).
In HUS, toxin-induced damage to the delicate cells lining the blood vessels causes clots, damage to red blood cells and kidney failure.
The international research team also included scientists from Monash University, the University of California (Davis and San Diego) and Emory University, Atlanta, Georgia.
"This research emphasises the need for people to eat only well-cooked red meat (particularly for hamburgers), or pasteurised dairy products, as these processes destroy contaminating bacteria," Professor Paton says.