Therefore, the main objective of this work was to evaluate the effect of PL and heat treatments, applied sequentially, on the inactivation of Bacillus subtilis spores. For that purpose, the influence of sublethal PL pre-treatments on spore heat resistance, as well as subsequent sensitivity to PL treatments after previous heat or PL processing and their persistence during storage under different conditions was determined. B. subtilis was used as challenge microorganism since it has been widely studied as a surrogate for other spore-formers and it is highly resistant to a variety of physical and chemical treatments ( Nicholson et al., 2000).