The lethal effect of PL on microorganisms is mostly attributed to
the photochemical action of the UV part of the spectrum emitted by
the flash lamp. Microbial DNA absorbs UV light that induces
chemical modifications in its structure, resulting in damage of
genetic information, impaired replication and gene transcriptionand eventually death of the cell (McDonald et al., 2002). Takeshita
et al. (2003) found that PL can also induce damage to membranes,
proteins and other macromolecules within microorganisms,
thereby increasing the efficiency of microbial inactivation.