FIG. 1.
Conceptual basis of the model for the lag time of L. monocytogenes in response to aw or pH shifts (dashed line) back and forth across the growth boundary (dotted line). The downshift to no-growth conditions induces “work to be done,” h1. The work to be done is carried out or increases at the rate ν = νa. The upshift to growing conditions also adds a supplementary workload, h2, which depends on the new conditions after the shift. Once the cells are in the growth region, adaptation is carried out at the rate ν = μmax.