Farm/Natural Selection Foods plant in San Juan Bautista has been linked to a nationwide E. coli outbreak that has killed one person and sickened nearly 100 others.

The E. coli outbreak is the sixth outbreak blamed on the nation’s fresh produce in five years, despite ever-tightening efforts to keep spinach and lettuce clean.

It was still unclear Saturday whether the outbreak concerned organically or conventionally farmed spinach, said Samantha Cabaluna, spokeswoman for Natural Selection Foods. The company produces both varieties in separate sections of its San Juan Bautista processing facility. For some labels like Dole, Natural Selection produces both organic and conventionally grown spinach, but for others like Trader Joe’s, the company packs only its organic variety while another producer packs the conventional kind.

Farmers say that unless the U.S. Food and Drug Administration retracts its warning against eating fresh packaged spinach their produce was worthless.The company, which processes spinach under many different brand names, including Earthbound Farms, began a voluntary recall Friday of all of its packaged spinach.