The United States Centers for Disease Control and Prevention (CDC) says that half of retail delis it surveyed failed to follow government guidelines for cleaning mechanical slicers.
They are a major source of Listeria cross-contamination and illness.
Meat slicers that had not been thoroughly cleaned and sanitized were found responsible for the Listeria-caused death of 22 people who ate meat from the Maple Leaf plant on Barton Road in Toronto in 2008.
The CDC picked 298 delis at random and found they were less frequently completely disassembled, cleaned and sanitized than the minimum of four hours specified in U.S. Food and Drug Administration food codes.
Slicers were fully cleaned more frequently in chain delis and in those that had more customers and slicers and required food safety training and written slicer cleaning policies.
The CDC recommended states and localities require deli manager training and certification and encourage written slicer cleaning policies.
Efforts should focus on smaller and independent delis that show lower frequencies of slicer cleaning, CDC said.