Abstract: The extraction conditions of total organic acid from Prunus mume was optimized and its inhibition on biofilm formation by Staphylococcus aureus was studied. The single factor and orthogonal test were used to optimize and verify the total organic acid extraction scheme of Prunus mume. The amount of biofilm formation by Staphylococcus aureus was determined by crystal violet staining. The results showed that the optimum extraction conditions of total organic acids were ethanol 70% （volume fraction）, solid-liquid ratio of 3 g / 40 mL, ultrasonic extraction time of 1.5 h and ultrasonic extraction temperature of 50 ℃. The extraction rate of total organic acid was 24.50% from Prunus mume under these conditions. The inhibitory rates on biofilm formation by Staphylococcus aureus was 13.06%,48.24% and 74.01% respectively at the extract concentration of 0.5MIC, MIC and 2MIC. Therefore, the extract could inhibit the formation of Staphylococcus aureus biofilm.

Key words: Prunus mume, total organic acid, method optimization, Staphylococcus aureus, biofilm