Cleaning and Sanitation of Salmonella-Contaminated Peanut Butter Processing Equipment

Food Microbiology. 2015;46:100-106

Abstract: 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 (90oC) 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.

This article can be found here. 

This work was supported by the ILSI North America Committee on Food Microbiology.