Combined effect of high hydrostatic pressure (HHP) and antimicrobial from agro-industrial by-products against S. Typhimurium

•The inactivation potential of cauliflower and mandarin by-products was studied.•The by-product infusions achieved 5 log cycles of microbial reduction at 37 and 10 °C.•The antimicrobial effect of HHP combined with two by-product infusions was evaluated.•When two treatments were combined, a synergistic effect was observed.•When two treatments were combined, the inactivation rates (Weibull) were greater.

The inactivation potential of HHP treatment (200 MPa-2 min) was evaluated against Salmonella enterica serovar Typhimurium in cauliflower and mandarin by-product infusions at 37 and 10 °C. By-product infusions exerted a strong antimicrobial effect used alone, achieving 5 log cycles of bacterial reduction for cauliflower by-product infusion after 10 h and for mandarin by-product infusion after 80 h, at 37 °C. The HHP treatment caused only one log cycle of cellular damage, but when inoculated cauliflower or mandarin by-product infusions were subjected to HHP treatment the antimicrobial effect against S. Typhimurium was enhanced, achieving 5 log cycles of inactivation in 6 h at 37 °C in both cases. Inactivation curves were adjusted to the Weibull equation and the kinetic parameters (b and n) were obtained. When HHP treatment was combined with by-product infusions, the inactivation rates were greater than when either of the by-product infusions was added separately. In conclusion, a synergistic antimicrobial effect against S. Typhimurium appeared to take place when HHP treatment was combined with cauliflower or mandarin by-product infusion. These infusions could be considered as an additional microbial control measure to guarantee the food safety and food quality of pasteurized food products that are stored under refrigeration.