Broken Arrow plant possibly linked to additional illnesses.

After Listeria in ice cream from Blue Bell Creameries sickened five adults in Kansas, the company announced Friday that it is voluntarily suspending operations at its manufacturing plant in Broken Arrow, OK.

“The Broken Arrow operations will be suspended so that our team of expert consultants can conduct a careful and complete examination to determine the exact cause of the contamination,” read a company statement. “We have notified the U.S. Food and Drug Administration of our action and we remain committed to being transparent with that federal agency. Once our investigation is complete and we have made all necessary improvements, it will return to operation.”

Initially, Kansas reported five people infected with one of four strains of Listeria monocytogenes who were all hospitalized at the same hospital for unrelated problems before developing listeriosis. Three of the patients subsequently died.

Of the four ill people for whom information is available on the foods eaten in the month before Listeria infection, all four consumed milkshakes made with a single-serving Blue Bell brand ice cream product called “Scoops” while they were in the hospital.

Whole genome sequences of Listeria monocytogenes strains isolated from these ice cream products were highly related to sequences of Listeria isolated from four of the patients.

The Blue Bell brand ice cream products were made at the company’s Brenham, Texas facility.

Investigators later isolated Listeria monocytogenes from single-serving Blue Bell brand 3-oz. institutional/food service chocolate ice cream cups (not “Scoops”) collected from the Kansas hospital and from the company’s Oklahoma production facility. These isolates were indistinguishable from each other by pulsed-field gel electrophoresis (PFGE).

The ice creams cups were recalled March 23.

CDC searched the PulseNet database and identified six patients with listeriosis between 2010 and 2014 who had Listeria isolates with PFGE patterns indistinguishable from those of Listeria isolated from Blue Bell brand 3-oz. institutional/food service chocolate ice cream cups. An investigation into whether these illnesses are related to exposure to Blue Bell products is ongoing.

“Based on the information CDC has at this time, we recommend that consumers do not eat any Blue Bell brand products made at the Oklahoma production facility and that retailers and institutions do not sell or serve them,” the agency stated in its outbreak update posted Friday evening.

Blue Bell brand products made at the Oklahoma production facility can be identified by checking for letters “O,” “P,” “Q,” “R,” “S,” and “T” following the “code date” printed on the bottom of the product package.