The high prevalence of S. aureus in retail beef livers is alarming and might be due to cross contamination since livers are recovered from several cows in slaughter houses and possibly piled up together. In Campylobacter, Ghafir et al. [41] suggested that the high level of recovery of the bacterium from livers is probably due to the fact that the liver surface stays moist, which might protect this foodborne pathogen. A possible explanation can be also true in S. aureus. Human handlers are possible sources of contaminating beef livers in slaughter houses. The risk of the high prevalence of S. aureus in beef liver in our study could be more severe due to the fact that livers are usually lightly cooked to avoid the undesired taste of overcooking. Adding to this risk is the fact that some S. aureus enterotoxins are heat stable. We have recently also found high prevalence of Campylobacter in beef livers [42] and chicken livers [43].