Effect of Oil and Dry Roasting of Peanuts at Various Temperatures and Times on Survival of Salmonella and Enterococcus faecium

ABSTRACT A number of outbreaks of salmonellosis since 2006 associated with the consumption of Salmonella-contaminated peanut butter have increased concerns about this food and the associated processing methods. Laboratory studies were conducted to determine the level of Salmonella reduction associated with oil and dry roasting of peanuts. After inoculation with either Salmonella or Enterococcus faecium, peanuts were dry roasted for various time durations at 5 temperatures ranging from 129–163 C and oil roasted at 120–160 C for three different time durations. At each dry roast combination of temperature and time in the study, Salmonella and E. faecium reductions were 2.7 log Colony Forming Units (CFU)/g or greater. Dry roast temperature of 154 C provided 4.6–4.7 log CFU/g reduction of Salmonella at 10 min and greater than 5.4 log CFU/g reduction at15 min. Oil roasting for 1.5 min at 150 C resulted in greater than a 6.0 log CFU/g reduction of Salmonella. E. faecium log CFU/g reductions were significantly le...