AUTHOR=Khodadad Christina L. M. , Hummerick Mary E. , Spencer LaShelle E. , Dixit Anirudha R. , Richards Jeffrey T. , Romeyn Matthew W. , Smith Trent M. , Wheeler Raymond M. , Massa Gioia D. TITLE=Microbiological and Nutritional Analysis of Lettuce Crops Grown on the International Space Station JOURNAL=Frontiers in Plant Science VOLUME=Volume 11 - 2020 YEAR=2020 URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.00199 DOI=10.3389/fpls.2020.00199 ISSN=1664-462X ABSTRACT=The ability to grow safe, fresh food to supplement packaged foods of astronauts in space has been an important goal for NASA. Food crops grown in space experience different environmental conditions than plants grown on Earth (e.g., reduced gravity, elevated radiation levels). To study the effects of space conditions, red romaine lettuce, Lactuca sativa cv 'Outredgeous', plants were grown in Veggie plant growth chambers on the International Space Station (ISS) and compared with groundgrown plants. Multiple plantings were grown on ISS and harvested using either a single, final harvest, or sequential harvests in which several mature leaves were removed from the plants at weekly intervals. Ground controls were grown simultaneously with a 24-72 hour delay using ISS environmental data. Food safety of the plants was determined by heterotrophic plate counts for bacteria and fungi, as well as isolate identification using samples taken from the leaves and roots.