Factors affecting microbial transfer of Salmonella enterica Enteritidis PT 30 and potential surrogate Enterococcus faecium NRRL B2354 during dry cleaning

Cross-contamination in dry food manufacturing environments contributes to Salmonella outbreaks in low-moisture foods (LMF). Dry cleaning methods are commonly used for cleaning interventions in LMF production environments. However, the influence of relevant factors on the transfer of Salmonella from food contact surfaces to cleaning tools during dry cleaning remains unclear. The survival of Salmonella enterica Enteritidis PT 30 ( S. PT 30) and its potential surrogate, Enterococcus faecium NRRL B2354 ( E. faecium ), was evaluated on Stainless Steel, High-Density Polyethylene, and Nitrile Rubber surfaces over 28 days. The effects of bacteria type, surface material, surface roughness, normal force, and shear force on the transfer of S. PT 30 and E. faecium from three surfaces were investigated using the spot inoculation method during dry wiping with a custom-designed dry cleaning platform. Surface material did not significantly affect the survival of both bacteria over 4 weeks ( p > 0.05). Bacteria type, surface material, and normal force had significant effects ( p < 0.05) on the microbial transfer to the paper towel. Based on the experimental results, E. faecium can be a potential surrogate for surface survival but not microbial transfer. The microbial transfer data generated in this study could help develop risk-based cross-contamination intervention models. • The scraped plate method generated higher bacteria count and desiccation tolerance • Bacteria, surface material, and normal force significantly impacted transfer and TC • E. faecium could be a suitable S. PT 30 surrogate for survival but not for transfer • Shear force significantly affected bacterial transfer on HDPE and Rubber