Scientific Publications by FDA Staff

Food Microbiol 2015 Apr;46:100-6

Cleaning and sanitation of Salmonella-contaminated peanut butter processing equipment.

Grasso EM, Grove SF, Halik LA, Arritt F, Keller SE

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 ( approximately 7 log CFU/g) was used to contaminate the equipment ( approximately 75 L). The system was then emptied of peanut butter and treated with hot oil (90 degrees 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 approximately 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/cm(2) remaining on processing equipment. After the isopropanol sanitation (+/-quaternary ammonium compounds), no Salmonella was detected in environmental samples on XLD (<0.16 log CFU/cm(2)). These data suggest that a two-step hot oil clean and isopropanol sanitization treatment may eliminate pathogenic Salmonella from contaminated equipment.