Texas-based Blue Bell Creameries says it's getting closer to identifying how listeria got into its facilities, after the century-old ice cream maker issued a massive recall because its products were linked to a deadly string of illnesses.
The company recalled all its products Monday after two samples of chocolate chip cookie dough ice cream tested positive for listeria.
Company spokesman Joe Robertson said Tuesday finding the cause is a matter of doing the needed investigation and consumers "are our No. 1 concern."
Blue Bell has a team of microbiologists working with officials at its four facilities in Texas, Oklahoma and Alabama. The company now plans to test all products produced at its facilities before sending them out to retailers.
The Centers for Disease Control and Prevention announced Tuesday the number of listeria illnesses linked to Blue Bell products has risen to 10.
The CDC had previously reported five illnesses from Kansas, including three deaths, and three illnesses in Texas. The agency said Tuesday that two more illnesses have been confirmed, one each in Oklahoma and Arizona.
Those sickened fell ill between January 2010 and January 2015.
The recall includes ice cream, frozen yogurt, sherbet and frozen snacks distributed in 23 states and abroad because the products "have the potential to be contaminated," according to the statement.
The company "cannot say with certainty" how the bacteria was introduced to its facilities, Blue Bell's chief executive Paul Kruse said in a statement.
"We're committed to doing the 100 percent right thing, and the best way to do that is to take all of our products off the market until we can be confident that they are all safe," Kruse said.
The first recall in the family-owned creamery's 108-year history was issued last month after the CDC and state health officials linked ice cream contaminated with listeria to the three deaths at a Kansas hospital.
The illness was tracked to a production line in Brenham, Texas, and later to a second line in Broken Arrow, Oklahoma. Monday's recall also applies to products produced in a Sylacauga, Ala plant.
The new samples of tainted ice cream were discovered through a testing program the company initiated after its first recall, according to the statement.
Monday's recall extends to retail outlets in Alabama, Arizona, Arkansas, Colorado, Florida, Georgia, Illinois, Indiana, Kansas, Kentucky, Louisiana, Mississippi, Missouri, Nevada, New Mexico, North Carolina, Ohio, Oklahoma, South Carolina, Tennessee, Texas, Virginia, Wyoming and international locations.
The manufacturing facility in Oklahoma where operations were suspended earlier this month for sanitizing will remain closed as Blue Bell continues to investigate the source of the bacteria, the statement said.
The CDC is trying to figure out where the bacteria is coming from and how many people have gotten sick from the ice cream.
“This is a bacteria that likes moist, damp, cold areas. It's possible to find out it's present in the plant but where, where is it hanging out, what equipment is contaminated,” explained Dr. Robert Tauxe, deputy director of the Division of Foodborne, Waterborne and Environmental Diseases at the CDC.
Tauxe is among the leaders of the team looking into the outbreak and how it began. He said this is the largest outbreak in the dairy industry to his knowledge.
“This is the first time it’s been a widely distributed commercial product that has affected so many people in so many places,” said Tauxe.
In compiling the information about the cases and the people who have fallen ill, a profile emerged.
“It's someone that is older who is already in the hospital for another reason and so therefore is at particular risk for listeria,” Tauxe said. “Essentially everybody seems to have acquired their infections while they were in the hospital for another reason.”
He said that includes the Texas cases.
Tauxe added the fact that cases date back to 2010 is telling about how long the contaminated ice cream has been produced.
“It’s possible that there has been occasionally, intermittently contaminated ice cream as far back as 2010,” he said.
Blue Bell is implementing a process to test all of its products before releasing them to the market, with plans to resume limited distribution soon.
The company said it is also expanding its cleaning and sanitization system, beefing up its employee training, expanding its swabbing system by 800 percent to include more surfaces and is sending daily samples to a microbiology laboratory for testing.
Listeria primarily affects pregnant women and their newborns, older adults and people with immune systems weakened by cancer, cancer treatments, or other serious conditions.
NBC 5's Ray Villeda and Scott Gordon contributed to this report.