1. Introduction
Modifications of food product formulations and processing
conditions to meet consumer demands for convenient, healthy or
“preservative-free” foods may concomitantly involve reduction of
food preservation hurdle intensities and subsequently lead to
sublethal stressing of microorganisms. As a result, surviving
damaged pathogens may have increased resistance and virulence
and thus be more difficult to control; and, as a result, antimicrobial
hurdles may fail (Doyle et al., 2006).
Bacteria may have various mechanisms for surviving these
external environmental stresses. If a population of microorganisms
is exposed to a sufficiently high concentration of an antimicrobial
compound, susceptible cells will be killed. However, some cells may
possess a degree of natural resistance or may acquire it later
through mutation or genetic exchange and will, therefore, survive
and grow (Davidson and Harrison, 2002). Sublethal injury is an
important aspect that should be considered in evaluating the