Antibiotics made some Africans feel better over 2000 years ago

I found this story from 2010 about a scientific discovery that suggests some Africans may have known about antibiotics more than 2000 years ago, a long time before the modern discovery. Analysis from  mummies from the ancient Nubians, who lived south of ancient Egypt in modern day Sudan, have shown that they drank beer which contained tetracycline, a type of antibiotics. The question is if the Nubians knew what they were doing?

"Given the amount of tetracycline there, they had to know what they were doing. They may not have known what tetracycline was, but they certainly knew something was making them feel better", biologival anthropologist George Armelagos told the site www.abc.net.au.