potential source and risk to the public has been stopped by closure of the restaurants in chipotle. until we know what the source is, what the product was, then we can't know it's not elsewhere and brings up the broader issue of multistate outbreaks of food associated illness. we've seen an increased number of recognized in recent years as we have looked more carefully. the reason we found this one is we're able to track the dna fingerprints of each of the patients who became ill to see whether they're related and when they are, we identify the source with the state and low call health departments on the front lines here. >> doctor, thank you for your time. i appreciate it. >> thank you. much more ahead in southern california in san diego. we have a standoff after shots fired. residents urged to stay inside. the latest after this break. beyond natural grain free pet food is committed to truth on the label. when we say real meat is the first ingredient,