Natural Selections spinachThe Associated Press reports that California health officials said Thursday they still hope to find the source of the contaminated spinach that’s sickened at least 189 people, but called on farmers to be more diligent about applying food safety measures to prevent future E. coli outbreaks.

The recent nationwide outbreak, at least the 10th traced to produce from California’s Salinas Valley during the last decade, shows that growers have not done all they could to safeguard their crops and the public’s health, said Dr. Kevin Reilly, deputy director of the prevention services branch of the California health department.

Meanwhile, the produce processing company at the center of the current E. coli outbreak announced Thursday that it would test a sample from each lot of greens its packages for illness-causing bacteria.

Natural Selection Foods CEO Charles Sweat said the new system is modeled after sampling procedures that helped reduce the number of human E. coli infections caused by beef. Natural Selection Foods LLC is a privately held company.

Besides testing produce for signs of contamination when it comes in, Natural Selections plans to develop food safety guidelines for the farmers whose produce it washes and packages, Sweat said. The new protocol will include audits on growers, internal audits on company staff and the enforcement of sanitation guidelines for farm equipment and packaging supplies.

Sweat said the company also will reach out to the people who were sickened by spinach packaged by their plant and offer to reimburse their out-of-pocket medical expenses.

"We know there are people out there who have suffered," he said. "It’s the right thing to do."