National Aeronautics and Space Administration scientists say two recent U.S. space missions have produced discoveries concerning salmonella bacteria.

Julie Robinson, a program scientist at NASA's Johnson Space Center in Houston, said the salmonella findings hold promise for improving ways to fight food-borne infections on Earth.

"This research opens up new areas for investigations that may improve food treatment, develop new therapies and vaccines to combat food poisoning in humans here on Earth and protect astronauts on orbit from infectious disease," said Robinson.

The salmonella experiments were flown on shuttle missions to the International Space Station in September 2006 and March 2008.

"The 2006 experiment results allowed researchers to identify a molecular 'switch' that appears to control salmonella's response to spaceflight in unique ways not observed using traditional experimental approaches on Earth," NASA said, noting the bacteria cultured in space were more virulent than those on Earth.

A research team led by Cheryl Nickerson at Arizona State University subsequently found adjusting the ion content of the bacteria's environment can turn off the rise in virulence caused by spaceflight. The study's findings appeared recently in the Proceedings of the National Academy of Sciences and in the online journal PLoS One.