Cocoa powder as a natural ingredient revealing an enhancing effect to inactivate Cronobacter sakazakii cells treated by Pulsed Electric Fields in infant milk formula

This work was carried out to study the potential effect of combining polyphenol-rich cocoa powder (CocoanOX 12%, CCX) with Pulsed Electric Field (PEF) technology to inactivate Cronobacter sakazakii cells inoculated into infant milk formula (IMF). ffect was studied for three different concentrations of cocoa powder, 1%, 2.5% and 5% (w/v), and for different addition times, 0, 2 and 4 h, before and after PEF treatment (15, 25 and 35 kV/cm), to determine the influence of both factors on inactivation and subsequent evolution of the treated cells under refrigerated conditions (8 °C, 12 h). sults indicated that combined PEF and CCX application, and the moment of CCX addition, pre-treatment/post-treatment, significantly affected the level of C. sakazakii inactivation achieved and subsequent evolution of the treated cells over 12 h at 8 °C (p ≤ 0.05). The maximum inactivation level, 4.41 log10 cycles, was achieved when CCX was added 4 h after PEF (15 kV/cm – 3000 μs) and the treated cells were kept under refrigerated (8 °C) storage for up to 12 h.