Follow CBSDFW.COM: Facebook | Twitter

BRENHAM (CBSDFW.COM) – Monday was a busy day at the Blue Bell plant in Brenham, Texas. Hundreds of employees spent the day at a training session led by a microbiologist.

READ MORE: Damage, Flooding Seen Throughout North Texas During Sunday Storms

In all, some 750 employees were briefed on how to control environmental conditions at the plant to prevent bacteria, including listeria. Company officials said this was the first step in the enhanced training program. Training sessions for supervisors will be conducted throughout the week.

As employees learned about contamination causes, officials with Blue Bell say they “continued to test individual pieces of equipment, the floor and other surfaces throughout its plants as it looks for the source or sources of the bacteria.”

It’s been exactly one week since Blue Bell voluntarily recalled ALL of their products, because of concerns about Listeria contamination. The ‘total recall’ of Blue Bell products happened after a recall weeks earlier was expanded to include products manufactured at a plant in Broken Arrow, Oklahoma.

READ MORE: 18-Year-Old Arrested In Connection To Murder Of Child Found In Dallas Street

There is no word on exactly when Blue Bell will resume production, but Greg Bridges, vice president of operations for Blue Bell said, “Our manufacturing facilities, especially the two in Brenham, are large and complex, so we anticipate this process will take some time. We appreciate the patience and understanding of our customers and retailers as we work to get this right.”

Laboratory tests of several different ice cream products, made at different plants, indicated the presence of Listeria, a bacterium that can cause severe illness. Symptoms of Listeriosis can include fever, muscle aches, diarrhea and vomiting. People with these symptoms should consult a physician.

Again, anyone with Blue Bell products in their home is being urged to return it to the place of purchase for a full refund. Consumers with morequestions can call 1-866-608-3940 Monday through Friday 8:00 a.m. to 8:00 p.m. or Saturday from 10:00 a.m. to 2:00 p.m. or click here for more information.

MORE NEWS: Storms In North Texas Spark Tornado Warnings Sunday Afternoon

(©2015 CBS Local Media, a division of CBS Radio Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)