The deaths of three people and illness in 200 others because of an E.coli outbreak in California spinach in 2006 shook the fresh produce industry.
Since then, farmers in Arizona and California, the two states producing almost all of the nation's leafy greens, have worked to develop new approaches to food safety.
Evidence of the work is visible in a romaine lettuce field in Yuma, where 20 workers emerge from the field and take turns washing their hands.
Before the E.coli outbreak, hand washing wasn't the norm, said Val Sierra, a food safety specialist for Amigo Farms.
"If they did wash their hands, a lot of people would just wet them, wouldn't use soap, probably dry them on their clothes," Sierra said.
Today there are signs posted in English and Spanish explaining the step-by-step procedure for proper handwashing.
"And you have to follow each step correctly in order to go back into the field," he said. "If not, you're not allowed."
In addition to this basic policy, Arizona and California came up with numerous joint strategies under the leafy greens food safety initiative, including testing and recording levels of potential contaminants in water and soil.
Participation in the program is voluntary. Once farmers are in, full compliance is enforced by state audits and with inputs from researchers who are keeping up with the latest in food safety science.
Kurt Nolte, director of the University of Arizona's Yuma Agricultural Center, said the center was the first to discover that drip irrigation - as opposed to using a sprinkler system - reduces the risk of microbial contamination such as salmonella, E.coli and listeria.
Read the rest of this Feb. 25th, 2015 Arizona Public Media article and listen to the interview at the link below.More Information