Currently, there is limited ability to follow Listeria monocytogenes through food-service environments, and there remain knowledge gaps concerning the underlying mechanisms that govern surface-to-surface transfer processes. Therefore, the objectives were to: (1) develop a method to quantify the spread of a physical surrogate, GloGermTM powder (GGP), between delicatessen meats and contact surfaces, and mathematically relate that to L. monocytogenes transfer under equivalent conditions; and (2) aggregate existing transfer data and compare candidate models across different transfer scenarios to elucidate phenomenological differences attributable to contact surface or product type. GGP and L. monocytogenes inoculated pieces (8 x 8 cm), of turkey, ham, stainless steel, or high-density polyethylene were placed in contact with an uninoculated surface of an opposite material (i.e., meat vs. equipment surface) for 12 sequential transfers. The GGP curves (photographed and quantitatively analyzed via image processing) were fit to the corresponding L. monocytogenes data by a linear adjustment, noting that parameters for recipient surfaces did not differ significantly (P > 0.05). Linear, Weibull, and two-phase linear- Weibull models were fitted to transfer curves encompassing the major ready-to-eat meat products, equipment surfaces, and contact events. The most likely models were determined using the Akaike Information Criterion. For slicing data, model choice was product dependent, but static contact data yielded the same model regardless of the meat type or surface, indicating fundamental differences among transfer responses.
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