Salmonella typhimurium cicc21484

Escherichia coli CICC 10003, Staphylococcus aureus CICC 10384, Listeria monocytogenes CMCC 54004, Salmonella typhimurium CICC 21484 were purchased from the China Center of Industrial Culture Collection (Beijing). Listeria monocytogenes CMCC 54004 was obtained from the College of Food Science and Technology, Yunnan Agricultural University (Kunming, Yunnan Province, China). Bacterial strains were conserved at -80°C in glycerol containing nutrient broth and were subcultured twice in Luria-Bertani broth medium under agitation (100 rpm) at 37°C for 24 h before use. The initial concentration of cells was adjusted to 10 6 cfu/mL by dilution in PBS (pH 7.4, containing 137 mM NaCl, 2.7 mM KCl, 10.1 mM Na 2 HPO 4 , and 1.8 mM KH 2 PO 4 , without calcium and magnesium) for subsequent experiments.
Human skin epithelial cells (HaCaT) were provided by the Moringa Institute of Yunnan Agricultural University. Cells were stored with 90% fetal bovine serum and 10% dimethyl sulfoxide at -80°C and cultured in RPMI 1640 medium containing 10% heat-inactivated fetal bovine serum (Hyclone Laboratories, Logan, UT) and 1% penicillin streptomycin antibiotic mixture (Gibco, Waltham, MA). All cell lines were cultured at 37°C in a humidified atmosphere at 5% CO 2 and 95% air.