Using Hyperspectral Fluorescence Spectra of Deli Commodities to Select Wavelengths for Surveying Deli Food Contact Surfaces

Abstract

Purpose: The inability to adequately judge the efficacy of cleaning and sanitation procedures in deli departments is arecognized food safety concern. In a prior study, our research group demonstrated that visual inspection of cleaned produceprocessing surfaces could be enhanced through the use of a portable fluorescence imaging device that detected residualproduce residues. Methods: To explore the feasibility of using fluorescence imaging to similarly detect residual deli residues,spectra of American, Cheddar, Provolone, and Swiss cheeses and of processed chicken, ham, roast beef, and turkey wereacquired using a laboratory hyperspectral imaging system. Circular punches of these commodities were placed ontostainless steel and high density polyethylene coupons for imaging. The coupon materials were selected to representcommon surfaces found in deli departments. Results: Analysis of hyperspectral fluorescence images showed that cheesesexhibited peaks in the blue-green region and at around 675 nm. Meats exhibited peaks in the blue-green region with one offour ham and one of four chicken brands exhibiting peaks at around 675 nm, presumably due to use of plant-derivedadditives. When commodities were intermittently imaged over two weeks, locations of spectral peaks were preserved whileintensity of peaks at shorter wavelengths increased with time. Conclusion: These results demonstrate that fluorescenceimaging techniques have the potential to enhance surface hygiene inspection in deli departments and, given the immediateavailability of imaging results, to help optimize routine cleaning procedures.