Use of a portable fluorescence imaging device to facilitate cleaning of deli slicers

•Tested use of fluorescence imaging for cleaning deli slicers.•After slicing and after cleaning, meat or cheese residues were detected using imaging.•Residues were detected by scanning at three wavelengths: 475, 520, 675 nm.•Cleaning the slicer required use of fluorescence imagining to direct cleaning efforts.•Fluorescent imaging should be of value for all deli cleaning and sanitizing efforts.

Cross-contamination is a recognized food safety concern for deli departments, and deli slicers remain a particular concern. This study examines the use of a fluorescence imaging device to detect deli residues on deli slicers. Four cheeses and four processed meats were used for testing. For each commodity, the slicer was scanned at 475, 520, and 675 nm after slicing five times, after washing, and after sanitation. A 405-nm light source was used to excite fluorescence responses. Hyperspectral data were acquired for identified problem areas, and the three wavelengths used for scanning proved adequate to detect all deli residues. Most residues were found in three areas: around the blade and blade guard, on the surface where commodities were pressed during slicing, and on and around the spikes in the arm used to hold commodities. The number of residues detected decreased with cleaning and then sanitation; however, it was impossible to fully clean the slicer without using the imagining device to direct cleaning efforts. It is suggested that a fluorescence imaging device, or something similar, be adopted for routine use in delicatessens.