Gerdes pointed out many instances when contamination could have occurred, including one in which Mazzola did not change her gloves between collection of two samples.
Mr. Mazzola, for his part, says his brainstorm to add a stirrer to a brewer was inspired by his grandmother, who would always stir whatever she was cooking on the stove.
Another witness, criminalist Andrea Mazzola, took the stand and, as she stated in the criminal trial, she said she tried to follow proper procedures when collecting evidence but admitted she didn't always do that.