Temperature, Time, and Type, Oh My! Key Environmental Factors Impacting the Recovery of Salmonella Typhimurium, Listeria monocytogenes, and Tulane Virus from Surfaces.

Environmental monitoring (EM) programs are designed to detect the presence of pathogens in food manufacturing environments, with the goal of preventing microbial contamination of food. Nevertheless, limited knowledge exists regarding the influence of environmental conditions on microbial recovery during EM. This study uses a commercially available polyurethane foam EM tool to determine the influence of environmental factors on the recovery of foodborne pathogens. The specific objectives of this study were to determine if environmental conditions and surface composition impact the recovery of sought-after microorganisms found in food processing environments. These data are compared across (i) microorganism type, (ii) surface type, (iii) environmental temperature and relative humidity (RH), and (iv) exposure time. Two bacteria (Listeria monocytogenes and Salmonella Typhimurium) and one human norovirus surrogate (Tulane virus) were inoculated onto three nonporous surfaces (polypropylene, stainless steel, and neoprene). Surfaces were held in an environmental chamber for 24 or 72 h at 30°C with 30% RH, 6°C with 85% RH, and 30°C with 85% RH. Data indicate that microbial recovery from environmental surfaces significantly (P ≤ 0.05) varies by microorganism type, environmental conditions, and exposure time. For instance, all microorganisms were significantly different from each other, with the greatest mean log reduction being Tulane virus and the lesser reduction being L. monocytogenes at 4.94 ± 1.75 log PFU per surface and 2.54 ± 0.91 log CFU per surface, respectively. Overall, these data can be used to improve the effectiveness of EM programs and underscores the need to better comprehend how EM test results are impacted by food manufacturing environmental conditions. [ABSTRACT FROM AUTHOR]