Then, between ages two and six, there was a big spike in antibiotics deposited in the bone, Armelagos said, suggesting that fermented grains were used as a weaning food.
Today, most beer is pasteurized to kill Strep and other bacteria, so there should be no antibiotics in the ale you order at a bar, said Dennis Vangerven, an anthropologist at the University of Colorado, Boulder.
But Armelagos has challenged his students to home-brew beer like the Nubians did, including the addition of Strep bacteria. The resulting brew contains tetracycline, tastes sour but drinkable, and gives off a greenish hue.
There's still a possibility that ancient antibiotic use was an accident that the Nubians never knew about, though Armelagos has also found tetracycline in the bones of another population that lived in Jordan. And VanGerven has found the antibiotic in a group that lived further south in Egypt during the same period.
Finding tetracycline in these mummies, said VanGerven, was "surprising and unexpected. And at the very least, it gives us a very different time frame in which to understand the dynamic interaction between the bacterial world and the world of antibiotics."