efficacy of any food preservation method because the presence of
injured bacterial cells could be as dangerous as the presence of fully
viable ones. Studies have shown that sublethally injured pathogens
could proliferate to microbiologically hazardous levels when water
and nutrients are plentiful (Busch and Donnelly, 1992; Ariefdjohan
et al., 2004) and they may acquire new or modified characteristics
(Lado and Yousef, 2002).
The Scientific Committee on Emerging and Newly Identified
Health Risks (SCENIHR, 2010) reported that the induction of a selective
pressure by the application of biocides that may favour the
selection of less susceptible bacteria and the expression and
dissemination of resistance mechanisms is not fully appreciated.
Biocides that include disinfectants and food preservatives have been
studied only recently. Food preservatives such as the terpenes
carvacrol and citral have been registered by the European Commission
for use as flavourings in foodstuffs because their use does
not present a risk to the health of the consumer (Burt, 2004). In fact,
natural antimicrobials are becoming popular in hurdle preservation
processes, allowing the use of mild treatments that minimally
penalize the sensory and nutritional properties of foods. Nonetheless,
caution must be exercised in light of the potential for bacterial
adaptation to these terpenes. Dubois-Brissonnet et al. (2011)
observed that the tolerance to disinfectants of cells cultivated with
sublethal concentrations of terpenes increased significantly for