Customers dine outside at a Chipotle Mexican Grill.

The U.S. Centers for Disease Control and Prevention has concluded its investigation into two E. coli outbreaks that sickened at least 60 Chipotle Mexican Grill customers in 14 states but said it was unable to determine the source of contamination.

The CDC said it was probably a common meal item or ingredient. That conclusion is simply not good enough. Without knowing precisely the cause of the outbreaks, how can Chipotle prevent them in the future?

Chipotle’s reputation, built on the promise of fast food made with fresh, locally sourced ingredients, has been hammered in recent months. Chipotle’s same-store sales dropped almost 15 percent last quarter and net income plummeted 44 percent, its first decline as a public company. Sales were down 30 percent in December and 36 percent in January, Chipotle reported on Feb. 2.

The company also reported receiving a subpoena expanding the scope of a federal criminal probe into a norovirus case at a Chipotle in Simi Valley in August. That outbreak sickened more than 200 customers and employees and was caused by an employee who had the highly contagious virus but wasn’t sent home from work.

The latest subpoena now covers “companywide food safety matters,” Chipotle said. A previous subpoena, served in December, was limited to one restaurant.

Regardless of how the criminal probe turns out, Chipotle faces higher marketing and food-safety costs as part of its comeback effort.

The company is adopting new protocols in its restaurants and supply chain that include quarterly food safety audits by third-party auditors, using bar codes to track supplies, testing high-risk items such as meat and vegetables, and tying store managers’ bonuses to audit results.

These seem like prudent steps for the company to take as it tries to lure back health-conscious burrito lovers and reassure investors that the illness outbreaks are a thing of the past. But the CDC’s failure to identify the cause of the E. coli incidents and the ongoing criminal probe over the Simi Valley norovirus outbreak means Chipotle’s recovery is far from certain.

Improving downtown Oxnard

Oxnard is getting serious about revitalizing its downtown, Business Times staff writer Marissa Nall reports in this issue.

A design team from the Congress for New Urbanism California is working with the city on a plan for downtown improvements.

Community members were asked for input at recent meetings and raised issues such as public safety, diversity of commerce and access to resources like transportation and the harbor.

The design team listened, put together some initial ideas and presented them at another public forum on Feb. 1. The team made a presentation to the City Council on Feb. 2 and was directed to incorporate the responses into a formal proposal for the city in five to six weeks.

Oxnard’s downtown could certainly use some improvements. We hope the city, residents and businesses can agree on a plan to revitalize the area.