A technique developed by USDA scientists for tracking pathogens has helped confirm that E. coli is not likely to contaminate the internal vascular structure of field-grown leafy greens and thus increase the incidence of foodborne illness.
ARS microbiologist Manan Sharma and other researchers, located at the environmental Microbial and Food Safety Laboratory in Beltsville, Maryland, have confirmed the pathogenic E. coli could survive in the soil for up to 28 days. They also observed that fluorescent E. coli cells were capable of migrating into the roots of spinach plants.
As for baby spinach, the team found that at day 28, there was no evidence that the E. coli had become "internalized" in leaves or shoots of baby spinach plants grown in pasteurized soil. However, E. coli could be detected in hydroponically-grown spinach samples, but its survival in shoot tissue was sporadic 28 days after the plants had germinated.