Effect of inoculation (pre‐ vs. post‐grinding) of black pepper on decimal reduction time of Salmonella spp. and Enterococcus faeciumNRRL B‐2354

Abstract

The laboratory inoculation techniques should ideally mimic the real‐life environment to reliably estimate the decimal reduction time (D‐value) of bacteria for process validation. This study aims at investigating the influence of the inoculation method on the D‐value of Salmonella in black pepper powder. Whole black peppercorns were either inoculated prior to grinding (pre‐grinding procedure) or ground and then inoculated (post‐grinding procedure). The ground black pepper was thermaly treated at 80°C for 0‐30 min. The D80°C values of Salmonella inoculated by pre‐grinding and post‐grinding procedures were 5.5 ± 0.8 and 3.9± 0.3, respectively. Salmonella and E. faecium were significantly (p⟨0.05) more thermally resistant in ground black pepper when inoculated pre‐ rather than post‐grinding. Therefore, inoculation protocol must be considered by spice industries while validating the pasteurization process. E. faecium is a suitable surrogate for Salmonella because of its higher decimal reduction time for both inoculation methods.