Inactivation of Staphylococcus aureus by high pressure processing: An overview

• A review on the inactivation of Staphylococcus aureus by high pressure processing (HPP) is presented.
• Factors conditioning the effectiveness of HPP in Staphylococcus aureus are approached.
• The inactivation of Staphylococcus aureus by HPP still is an existing challenge.

Food safety is a major concern of consumers, food industry and governments, with 25 million foodborne diseases occurring annually worldwide. Staphylococcus aureus, is an extremely versatile opportunistic pathogen being responsible for staphylococcal food poisoning due to enterotoxic strains. With increasing demands for safer food, new food preservation technologies are increasingly gaining interest. In the last two decades, high pressure processing (HPP) appeared as an alternative non-thermal food preservation method promoting inactivation of some spoilage and pathogenic microorganisms, while maintaining food characteristics. Factors that modulate its efficiency will be revised, firstly based on the state-of-the art described for bacteria in general and afterwards, when studies exist, for S. aureus specifically. S. aureus inactivation by HPP, like in other microorganisms, is conditioned by cell structures and biomolecules, matrix, HPP processing conditions, the use of antimicrobials and is also dependent of the strain and growth phase. Cell membrane is the most pressure sensitive structure of S. aureus, being the lipids and proteins the most important target molecules. However, monomeric proteins such as staphylococcal enterotoxins (SE) are not affected by HPP, and strains with SE appear to be more efficiently inactivated than those without. Other phenotypic and genotypic characteristics of S. aureus strains, such as pigmentation and the presence of σB factor are extremely important factors determining the efficacy of HPP treatments. Inactivation of S. aureus by HPP to ensure food safety still remains a current challenge regarding the understanding of its particular barotolerance and its inactivation kinetics profile that often deviates from the simpler first order decay. Thus, this review provides state-of-the-art information for researchers interested in studying HPP inactivation of S. aureus.Industrial relevanceThis review gives an insight on the importance of Staphylococcus aureus as a foodborne versatile opportunistic pathogen and its importance from the food safety point, its barotolerance and the main reasons for this resistant behavior to high pressure processing and the mechanisms of S. aureus inactivation by HPP.