The European General Food Law of 2005 and the newly promulgated FDA Food Safety Modernization Act (FFSMA) of 2010 ask all food operators to implement preventive efforts. In this article, we explore the link between firm’s size and preventive efforts. We show two main results. First, when there is no cross-contamination, small firms will provide higher preventive efforts than large firms. When there is crosscontamination, the effort-size curve may have a "inverted-U" shape. From our results we can argue that when implementing or enforcing food safety regulations, public authorities should consider both firms size and food safety hazard.