Tampering is not suspected in an outbreak of E. coli linked to fresh spinach, federal health officials said Monday as they continue to probe the source of the contamination and warned consumers to continue to avoid fresh spinach products.

Finding spinach at Athens restaurants or grocery stores might be a little difficult since the recent findings.

“We’re not serving it at all,” Athens Ruby Tuesdays’ employee Kim Brown said Monday.

She said they are not offering the vegetable on the salad bar nor using it in food preparation. She said spinach is not currently even in the restaurant.

As for Southern Family Markets, which operates two businesses in Athens, Karen Adelman with CNS Wholesale Grocers, said the company that owns Southern Family Markets, didn’t know what the local stores were doing about the problem.

However, she did say that they are definitely in compliance.

The Food and Drug Administration has linked a California company’s fresh spinach to the outbreak, which has killed one person and sickened at least 109 others. Investigators are working to pinpoint the source of the bacteria. Possible sources include contaminated irrigation water.

“At this time we have no evidence supporting tampering,” FDA spokeswoman Susan Bro said.

Bro also dismissed a claim by Natural Selection Foods LLC, the country’s largest grower of organic produce, that its organic spinach products had been cleared of suspicion. “The FDA has not cleared any products from the list and continues to recommend consumers avoid eating fresh spinach products,” Bro said.

Natural Selection has maintained its recall of 34 brands of fresh spinach products. However, the company said late Sunday the manufacturing codes from packages of spinach that had infected patients turned over to health officials all were from non-organic spinach. The company packages both organic and conventionally grown spinach in separate areas at its San Juan Bautista, Calif. plant.

Those brands include the company’s own labels and those of other companies that had contracts with Natural Selection to produce or package its spinach.

Meanwhile, Salinas-based River Ranch Fresh Foods added to its recall spring mixes containing spinach sold under the labels Hy-Vee, Fresh N’ Easy and Farmers Market, FDA officials said. All contain spinach purchased from Natural Selection, they said.

The FDA and California Department of Health Services planned Monday to work toward tracing the infected greens to individual farms. The inquiry will review irrigation methods, harvest conditions and other practices at farms possibly involved.

The spinach could have been contaminated in the field or during processing. About 74 percent of the fresh-market spinach grown in the U.S. comes from California, according to the California Farm Bureau Federation.