Web Editor's note: Read even newer coverage on this story in our Oct. 22 article, "Texas regulators’ scrutiny focuses solely on Sangar."

Texas health officials have shut down San Antonio-based Sangar Fresh-Cut Produce after they traced listeria deaths and illnesses earlier this year to fresh-cut celery from the plant.

The department investigated 10 listeria cases, including five deaths, reported in Bexar, Travis and Hidalgo counties over eight months. Six of the 10 cases are linked to chopped celery from Sangar’s plant, according to a Texas Department of State Health Services news release.

It was not immediately known how many of the deaths were traced to Sangar products, or when the last case was reported. State health officials did not respond to requests for comment Oct. 21.

Sangar officials also did not respond to requests, but company president Kenneth Sanquist Jr. told the Associated Press he blames state inspectors’ lax sampling techniques for linking Sangar to the outbreak. The sample at the plant, Sanquist said “appears” to have been taken by someone not wearing proper lab attire and gloves, and was transported in a nonrefrigerated container.

“We question the validity of the state’s lab results,” Sanquist said in the statement to the AP.

The recalled products, mostly fresh-cut produce in sealed packages, were distributed through foodservice channels to restaurants, hospitals and schools. They are not believed to have been sold at retail, according to the DSHS, which ordered a recall of all the company’s products shipped since January.

The Oct. 20 order was issued after samples of chopped celery from the plant tested positive for Listeria monocytogenes.

All of the illnesses affected people with serious underlying health problems, according to the release.

Texas inspectors also found sanitation issues at the plant and believe the listeria found in the chopped celery may have contaminated other food produced there, according to the DSHS. Findings included a condensation leak above a food product area, soil on a preparation table, and hand washing issues.

Bob Whitaker, chief science and technology officer at the Produce Marketing Association, said that while it’s too soon to rule out additional sources of contamination, the focus of the investigation appears narrow.

“At this point we’re waiting for more information to see where this goes,” Whitaker said. “This has been going on for a while and there are serious consequences. But it seems localized.”

Complete tracing can be painstaking and time-consuming, Whitaker said.

“People have a hard time remembering what they ate, and so it can be difficult to make those connections after a while,” he said.

DSHS food safety personnel are contacting distributors, restaurants and institutions believed to have received the recalled products.

The order prohibits the Sangar plant from reopening without DSHS approval.