Purpose: Evaluate the heat resistance of Enterococcus and Salmonella on Nonpareil whole, Monterey whole/broken, Natural splits, and Natural dice in an oven at 280°F/15 min after 0, 14, and 28 days of storage at 4°C.
Methods: Almond products were inoculated with Enterococcus or Salmonella and stored at 4°C for 28 days. The inoculated almonds were heat-treated after 0, 14, and 28 days of storage. Log reductions for almond products following heat treatment at each sampling time were compared using ANOVA.
Results: Log reductions of Enterococcus or Salmonella for each type of almond (except Enterococcus on Monterey whole/broken) following heat treatment over 28 days of storage were not significantly different (P > 0.05) and ranged between 0.29 ± 0.20 and 2.37 ± 1.09 logs (n = 9), or 0.91 ± 0.33 and 2.26 ± 0.59 logs (n = 9) for Enterococcus or Salmonella, respectively. No significant differences (P > 0.05) were observed between log reduction of Enterococcus and Salmonella for each type of almonds at each sampling time. Heat resistance of Enterococcus or Salmonella at each sampling time was significantly different (P < 0.05) based upon almond type; however, the average log reduction for all cases was less than 2.5 logs.
Significance: The shelf life of Nonpareil whole, Natural splits, and Natural dice almonds inoculated with Enterococcus can be extended to 28 days at 4°C without significant impact to the heat resistance of this organism. Enterococcus is an appropriate surrogate for Salmonella on all four almond types.