50 years ago, scientists first investigated antibiotic resistance in livestock

Excerpt from the June 27, 1970 issue of Science News

a photo of livestock cows

Decades of research into the effects of feeding antibiotics to cows and other livestock to boost their growth has revealed that the practice can be problematic for humans.

Artem Zakharov/iStock/Getty Images Plus

Panel to study animal feedsScience News, June 27, 1970

Most animal feeds contain antibiotics … to promote fast weight-gain in species raised for human food. However, these animals may harbor microorganisms that have developed a resistance to antibiotics, and some scientists fear that these resistant organisms may be passed on to human beings…. [The U.S. Food and Drug Administration has appointed a panel to review whether] antibiotic resistance in man is enhanced by long-term, low-level exposure from foods.


The first hint that antibiotic-resistant bacteria in livestock can jump to humans came in 1976, when scientists found higher levels of such bacteria in the guts of farmers who fed antibiotics to chickens than in those farmers’ neighbors. In terms of the food supply, the FDA has detected varying levels of antibiotic-resistant bacteria in meat since monitoring began in 1996. Cooking should kill these bacteria, though some have been linked to illness in humans. Since 2013, the FDA has phased out the use of antibiotics for promoting growth in livestock.

Jonathan Lambert is a former staff writer for biological sciences, covering everything from the origin of species to microbial ecology. He has a master’s degree in evolutionary biology from Cornell University.