*2.4. Verification of the Drug-Resistant Bacteria*

The verification assay was undertaken using the agar dilution method following the testing procedures of the Clinical and Laboratory Standards Institute, USA (CLSI M100-S28, 2018). Briefly, tested strains were cultured in MH broth overnight, then centrifuged (1000× *g*, 1 min) and transferred to a custom 96-well microtitre plate using 1 mL of 0.85% sodium chloride solution. The absorbance of bacterial resuspension at OD 600 was adjusted to 0.5, followed by further 100 fold dilution to make a final concentration of 1 <sup>×</sup> 106 CFU/mL. Subsequently, bacterial suspensions were incubated to the MH agar plates which were supplemented with antibiotics under prescribed breakpoint concentrations stated by CLSI using the multipoint incubator (HM1-12-001, Hen Gao Technology Development Co., Ltd., Tianjin, China), and the plates were cultured at 37 ◦C for 20 h. In addition, the oxacillin agar dilution method was used for the detection of MRSA (CLSI, 2018). Isolates were considered to be multi-drug resistant if they were resistant to at least three different categories of antibiotics, based on their growth condition on the MH plates.

## *2.5. Preparation of Spice Ethanolic Extracts*

The clean dietary spices were air-dried in a ventilated oven at 40 ◦C for 24 h, then ground into fine powders by a miller (S025, IKA, Staufen, Germany). Powdered samples (4.0 g) were extracted with 80 mL of 80% (*v*/*v*) ethanol in a shaking bath (MQT-50, Shanghai Min Quan Co., Ltd., Shanghai, China) at room temperature (23 ± 1 ◦C) for 24 h. In this study, 80% ethanol was used for the extraction, since ethanol is of relative low toxicity among several organic solvents, and 80% ethanol was efficient to extract antioxidant and antibacterial components from spices and herbs based on our previous study [22]. Afterwards, the mixture was centrifuged at room temperature (900× *g*, 15 min) and the collected supernatant was concentrated by a rotatory vacuum evaporator (RE-52AA, Shanghai Ya Rong Co., Ltd., Shanghai, China) at 40 ◦C, then the concentrated extract was dried by a vacuum freeze-dryer (SJIA-5FE, Ningbo Shuang Jia instrument Co., Ltd., Ningbo, China). The freeze-dried samples were stored at −20 ◦C in small vials for further use.
