LOS ANGELES – For days, the speculation has been rampant: Which Mexican food chain — identified only as “Restaurant Chain A” by federal investigators last month — was linked to a large salmonella outbreak late last year?

This week, Food Safety News named Taco Bell as the chain in question.

In October and November, at least 68 diners were sickened across 10 states, including 16 in Oklahoma and 43 in Texas. The spate of illnesses eventually petered out and was reported by the Centers for Disease Control on Jan. 19.

But the agency stayed silent on the origin of the salmonella bacteria, saying only that the majority of victims had reported eating at 18 separate locations of “a Mexican-style fast-food restaurant chain” in the Midwest.

Salmonella can cause diarrhea, abdominal cramps, fever, nausea, vomiting, fatigue and other symptoms.

The CDC said that investigators were unable to narrow down which ingredient was problematic, saying that 94 percent of victims reported eating ground beef, 90 percent said they ate lettuce and 77 percent had consumed cheese.

The agency concluded that the salmonella contamination likely happened before the food reached the restaurants and that the meat probably was not the culprit.

But the blogosphere remained eager to identify the restaurant at the center of the outbreak, whose name the CDC still refuses to disclose.

“It’s been a longstanding CDC policy that if it is not beneficial toward public health, we don’t release the name of the restaurant or the entity,” spokeswoman Lola Russell said. “The outbreak is over and has been over.”

Nevertheless, Food Safety News obtained a document from the Oklahoma State Department of Health showing that many of the interviewed victims had eaten at a Taco Bell during the exposure period.

In a statement, Taco Bell said that it takes food quality and safety very seriously and emphasized that public health is not at risk now that the incident is over.

Taco Bell was linked to salmonella outbreaks in 2010 that sickened more than 100 people as well as an E. coli incident in 2006 that left dozens ill.