Cleaning and sanitation of Salmonella-contaminated peanut butter processing equipment

•Hot oil alone is not sufficient to remove Salmonella on processing equipment.•Hot oil may be a viable first step in a two part cleaning-sanitization process.•Hot oil followed by 60% isopropanol removes Salmonella on processing equipment.•Hot oil followed by isopropanol + QACs removes Salmonella on processing equipment.

Microbial contamination of peanut butter by Salmonella poses a significant health risk as Salmonella may remain viable throughout the product shelf life. Effective cleaning and sanitation of processing lines are essential for preventing cross-contamination. The objective of this study was to evaluate the efficacy of a cleaning and sanitation procedure involving hot oil and 60% isopropanol, ± quaternary ammonium compounds, to decontaminate pilot-scale processing equipment harboring Salmonella. Peanut butter inoculated with a cocktail of four Salmonella serovars (∼7 log CFU/g) was used to contaminate the equipment (∼75 L). The system was then emptied of peanut butter and treated with hot oil (90 °C) for 2 h followed by sanitizer for 1 h. Microbial analysis of food-contact surfaces (7 locations), peanut butter, and oil were conducted. Oil contained ∼3.2 log CFU/mL on both trypticase soy agar with yeast extract (TSAYE) and xylose lysine deoxycholate (XLD), indicating hot oil alone was not sufficient to inactivate Salmonella. Environmental sampling found 0.25-1.12 log CFU/cm2 remaining on processing equipment. After the isopropanol sanitation (±quaternary ammonium compounds), no Salmonella was detected in environmental samples on XLD (<0.16 log CFU/cm2). These data suggest that a two-step hot oil clean and isopropanol sanitization treatment may eliminate pathogenic Salmonella from contaminated equipment.