Abstract

Staphylococcus aureusis a common food pathogen and has a strong tolerance to environmental stress. Here, the biofilm formation ofS. aureusstrains after cold stress for 24 weeks were investigated. It was found that the biofilm formation ofS. aureusCICC 21600, CICC 22942, W1, W3, and C1 cells was enhanced after cold stress for 20 weeks. What is more, the mRNA levels of theclfA,icaA,icaB,icaCoricaDgenes in these strains were increased for >2-fold. The increased gene transcription levels were consistent with the increase in the polysaccharide content in the biofilm matrix of theseS. aureusstrains after cold stress. Meanwhile, hydrophobicity and the adhesion proteins also played a role in the formation of biofilms. The biofilm ofS. aureuscells can be effectively degraded by snailase and proteinase K (125 µg/mL + 20 µg/mL) mixture. In summary,S. aureusfrozen at −20 °C for 12 to 20 weeks is still a potential hazard. Food factory equipment should be cleaned in a timely manner to avoid outbreaks of foodborne pathogenic bacteria due to contamination.Keywords:foodborne pathogens;cold stress;biofilm;polysaccharide intercellular adhesion