Salmonella cross-contamination in flour production facilities remains a recalcitrant problem, requiring effective low-moisture cleaning and sanitation. For research on this topic to be effective, dry inoculation methods must accurately model the powder accrual and the transfer of Salmonella from flour to equipment surfaces. Additionally, radiative sanitation technologies could provide quick and effective surface sanitation, given a sufficient intensity. Therefore, it is necessary to understand the relationship between radiation dosage and Salmonella reduction on stainless-steel (SS) surfaces. The objectives of this research were to (1) develop a replicable methodology employing electrostatic powder coating technology to apply inoculated, fabricated all-purpose flour onto SS surfaces, (2) generate the efficacy data for radiative dry sanitation technologies (UV-C, Far UV-C, and Infrared) achieving minimum 3 log reduction of Salmonella (log CFU/cm2), and (3) develop surface inactivation models for the Salmonella on visibly clean SS surfaces in low-moisture environments. All-purpose wheat flour was fabricated and inoculated with a 6-strain Salmonella cocktail. The inoculated flour was adhered to #304 and #316 grade SS using an electrostatic powder coating apparatus. Subsequently, the SS was cleaned with a brush until visibly clean and then exposed to UV-C, Far UV-C, and IR radiation. Thereafter, the surface inactivation models were developed based on the log population counts remaining on SS surfaces and the total energy deposited as a function of the applied radiation intensity and the duration of radiation exposure. The dry powder coating inoculation methodology proved to be consistent and replicable at pilot scale, achieving ~4 log CFU/cm2 on the surface of #304 brushed finish and #316L brushed finish SS coupons. Furthermore, this study demonstrated the potential application of UV-C and IR technologies for dry sanitation on visually clean, stainless steel surfaces across various grades and finishes.
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