Alicyclobacillus acidoterrestris spore inactivation by high pressure combined with mild heat: Modeling the effects of temperature and soluble solids

The soluble solids increased the resistance of the spores to 600 MPa-thermal process, while the temperature decreased its resistance. Although the nonlinear Weibull model gave better fittings, the first-order kinetic parameters were also determined. For example for 600 MPa at 55 °C D10°Brix = 4.2 min, D20°Brix = 7.6 min, D30°Brix = 13.7 min, and zT-values were 20-21 °C. The z-values for the effect of soluble solids on DT-values were 39-40 °Brix for 45 and 55 °C 600 MPa HPP. The results obtained with broth were validated with fruit juices and concentrates. The combination of HPP with heat was an effective alternative to conventional thermal processing for the inactivation of A. acidoterrestris spores in juices up to 30 °Brix, allowing the use of less 30-40 °C of temperature for the same microbial inactivation, which potentially results in more nutritious, fresher and tastier juices/concentrates.