The U.S. Centers for Disease Control and Prevention (CDC) has published a study that delves into how often deli slicers are cleaned at the retail level. Deli foods are most commonly associated with Listeria monocytogenes contamination.

The study--conducted by the CDC’s Environmental Health Specialists Network--looked at how often retail deli slicers were disassembled, cleaned and sanitized at 50 delis from January through September of 2012. Their observations were based upon the U.S. Food and Drug Administration’s (FDA’s) Food Code-specified minimum frequency of every 4 hours. Also, deli staff members at 298 randomly selected delis were interviewed regarding their deli cleaning methods.


  • About 50 percent of all surveyed delis fully cleaned their deli machines less frequently than the FDA’s minimum requirement.
  • Retail chain delis--equipped with written cleaning policies, food safety-trained management and more slicers--cleaned their equipment more frequently than delis without those qualities.
  • Overall, retail delis were found to have cleaning frequencies at lower rates than suggested, a practice that puts consumers at risk for foodborne illness. Larger chains have the resources and training to perform better and more frequent equipment cleanings than smaller, independent retailers.
  • The study also makes clear that there is a direct correlation between food safety training and certification and frequency of deli slicer cleaning.

For this particular study, data was only collected from English-speaking deli staff members and managers.

While the CDC and the FDA encourage that all retailers implement the FDA Food Code--last updated in 2013--not all states and local establishments have done so.

According to the CDC, Listeria monocytogenes causes the third highest number of foodborne illness deaths in the United States annually. Listeria contamination of sliced deli meats at retail locations contributes to Listeria illness and outbreaks. Mechanical slicers pose cross-contamination risks in retail delis and are an important source of Listeria cross-contamination. Good slicer cleaning practices can reduce this risk.

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