Outbreak investigators say a cattle feedlot near a canal providing water to growing regions in Arizona is a key element in their hypothesis about the source of E. coli that contaminated romaine lettuce earlier this year.

The Food and Drug Administration has been investigating the outbreak, linked to romaine grown in the Yuma, AZ, area…

We’ve been reporting on the E. coli outbreak linked to romaine lettuce since federal officials first announced it on April 13. Actually, though romaine hadn’t been connected to it yet, we started reporting on the outbreak April 4. A day earlier New Jersey health officials had alerted the public to a cluster of…