Two days after Blue Bell Creameries voluntarily recalled all of its products, the 100-year-old business says it’s making progress in pinpointing the cause of a massive listeria contamination that has led to three deaths and at least 10 illnesses.

The Texas-based ice cream company announced Tuesday that it is stepping up efforts – including the hiring of a team of microbiologists – to quickly identify the cause of the listeria contamination, the Chicago Tribune reports.

The microbiologists are currently working with federal investigators at Blue Bell’s four production facilities located in Texas, Oklahoma and Alabama.

“As each day passes, we are getting closer and closer to figuring out how this listeria was introduced into our facilities. … It’s a matter of doing the work and not making excuses,” a representative for Blue Bell tells the Tribune.

In addition to hiring the microbiologists, Blue Bell says it will expand its cleaning and sanitation system, increase employee training and expand a swabbing system to include more surfaces. The company is also sending daily samples to labs for testing.

At the same time that Blue Bell announced its beefed up efforts, the Centers for Disease Control and Prevention announced that the number of consumers sickened by the listeria contamination grew to include 10 people in four states.

In all, the contamination has sickened five people – three of whom later died – have become ill in Kansas, three in Texas and one each in Arizona and Oklahoma.

According to the CDC, the illnesses began anywhere from January 2010 through January 2015. One additional patient with listeriosis is undergoing further testing to determine if that illness is related to the Blue Bell contamination.

“CDC and state and local public health partners are continuing laboratory surveillance through PulseNet to identify any other ill persons that may be part of this outbreak,” the agency said in an update to the case.

On Monday, Blue Bell added to three earlier recalls by pulling all products off the shelves after two more ice cream samples tested positive for listeria.

The massive voluntary recall was initiated after two chocolate chip cookie dough ice cream samples tested positive for the potentially deadly bacteria.

The final recall includes frozen yogurt, sherbet and frozen snacks distributed in 23 states as well as internationally, because those items “have the potential to be contaminated,” the company said.

CEO Paul Kruse said in a video statement posted on Blue Bell’s website Monday, that the company couldn’t say how the listeria was introduced to its facilities.

For several weeks, the contamination was thought to only be present in the company’s temporarily closed Broken Arrow facility.

After that contamination was confirmed a number of retailers, including Sam’s Club, Walmart, H-E-B, and Kroger, began remove Blue Bell products.

Blue Bell products being recalled are distributed to retail outlets, including food service accounts, convenience stores and supermarkets 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.

Consumers should not eat any Blue Bell products — if you have them in your freezer, throw them out or return them to the store where you purchased them for a full refund, even if no one has gotten ill from eating them.

Blue Bell says it’s still trying to pinpoint listeria cause [The Chicago Tribune]

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