Ohmic heating increases inactivation and morphological changes of Salmonella sp. and the formation of bioactive compounds in infant formula

The effect of ohmic heating (OH) (50, 55, and 60 degrees C, 6 V/cm) on the inactivation kinetics (Weibull model) and morphological changes (scanning electron microscopy and flow cytometry) of Salmonella spp. in infant formula (IF) was evaluated. In addition, thermal load indicators (hydroxymethylfurfural and whey protein nitrogen index, HMF, and WPNI) and bioactive compounds (DPPH, total phenolics, ACE, alpha-amylase, and alpha-glucosidase inhibitory activities) were also studied. OH presented a more intense inactivation rate than conventional heating, resulting in a reduction of about 5 log CFU per mL at 60 degrees C in only 2.91 min, being also noted a greater cell membrane deformation, higher formation of bioactive compounds, and lower values for the thermal load parameters. Overall, OH contributed to retaining the nutritional value and improve food safety in IF processing.

Automated summary

Ohmic heating showed a more intense inactivation rate of Salmonella spp. in infant formula, with a reduction of about 5 log CFU per mL at 60 degrees C in only 2.91 min. It also resulted in greater cell membrane deformation, higher formation of bioactive compounds, and lower values for the thermal load parameters, contributing to retaining the nutritional value and improving food safety in infant formula processing.