Staphylococcus aureus contamination is a risk factor for food safety in quick-frozen dumpling products. Biofilms represent a potential source of bacterial contamination in food processing. In order to study biofilm formation characteristics of S. aureus in quick-frozen dumpling products and the resistance to disinfectants, the investigations were carried out using strains isolated from the products. Biofilm forming ability of the isolates were investigated including biofilm formation on the surface of polystyrene (PS) and stainless steel (SS), presence of adhesion genes, effects of environmental conditions, and bactericidal effects of three disinfectants against biofilm cells. The results showed that the isolates formed stronger biofilms on the surface of SS than PS. More than four adhesion genes were detected in each isolate. The presence rate of eno and clfB genes were 100%, whereas bap gene was not detected in any of the isolates. On the surface of SS, the presence of sasG showed highly significant positive correlation with biofilm formation (P<0.01), and clfA and fnbA showed significant positive correlation with biofilm formation respectively (P<0.05), while that of icaAD, icaBC and fib showed highly significant negative correlation (P<0.01). On the surface of PS, the presence of sasG showed a significant positive correlation with biofilm formation (P<0.05), and fib showed a significant negative correlation (P<0.05). The optimal growth temperature of 37 ℃ was favorable for the formation of more biofilms. At room temperature (25 ℃), the strains still formed relatively high biomass of biofilm. The largest amount of biofilm was observed to form at pH 7. Under weak acidic and weak alkaline conditions, the biofilm formation was less affected. At NaCl<5%, a certain stimulating effect was observed on the film formation. The biofilm greatly enhanced the resistance of the cells wrapped inside to the disinfectant tested. Among the three disinfectants tested, peracetic acid was found to be the most effective against biofilms cells. The results provide new data for the study of biofilms formed by S. aureus in quick-frozen dumplings, laying the basis for further prevention and reduction of the harm of the biofilm.
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