The outbreak sickened eight maximum-security inmates at the state prison in Salt Lake County on October 2011.
The CDS said in a report last week that the inmates made several batches of cell brew with fruit, water and sugar, but only one contained a potato believed to have made inmates sick.
Botulism is a rare but serious illness that can cause paralysis, even death. Symptoms include double vision, difficulty swallowing and muscle weakness.
The botulism outbreak was the second largest in the country since 2006. Ten people were sickened in a 2007 outbreak linked to widely distributed hot dog chili sauce.