Different model hypotheses are needed to account for qualitative variability in the response of two strains of Salmonella spp. under dynamic conditions

•Strain variability causes quantitative and qualitative differences for microbial inactivation.•Salmonella Enteritidis had linear isothermal curves and developed stress acclimation.•Salmonella Senftenberg had non-linear isothermal curves and did not develop acclimation.•Strain variability may imply not just different parameter values, but also model hypotheses.•Model hypotheses must be carefully evaluated under isothermal and dynamic conditions.