Purpose: This study was conducted to quantify the transmission of Listeria monocytogenes and Salmonella spp. from contaminated cutting boards to fresh tomato and kale.
Methods: Cocktail inocula of L. monocytogenes and Salmonella spp. were used to spot inoculate stainless steel, bamboo, and pressed paper surfaces. Kale leaves and whole grape tomatoes were pressed to surface coupons, with an equal amount of force (approximately 320g), for three seconds. The samples were homogenized and serial dilutions were made for enumeration, after 24 hours of incubation at 37ºC. The experiments were repeated eight times. The concentrations were calculated and the collected data were analyzed using SPSS.
Results: The transfer of pathogens to kale [3.83±0.42 log CFU/mL] was consistently higher than to tomatoes [3.63±0.51 log CFU/mL] [P<0.05]. Bacteria transferred at a similar rate from all types of surfaces (cut bamboo, bamboo, stainless steel, cut paper, and paper) [P=0.310] under the studied conditions (wet surfaces). The transfer of Salmonella spp. [3.74±0.54 log CFU/mL] was significantly higher than that of L. monocytogenes [3.71±0.39 log CFU/mL] [P=0.01].
Significance: The data from these experiments highlight the importance of maintaining sanitary kitchen surfaces. For food safety, clean cutting boards must be used to cut and prepare fresh produce, as pathogens on the surface of cutting boards can be readily transmitted.