Effect of NaCl on Heat Resistance, Antibiotic Susceptibility, and Caco-2 Cell Invasion of Salmonella

Abstract EN

This study evaluated the effects of NaCl on heat resistance, antibiotic susceptibility, and Caco-2 cell invasion of Salmonella.

Salmonella typhimurium NCCP10812 and Salmonella enteritidis NCCP12243 were exposed to 0, 2, and 4% NaCl and to sequential increase of NaCl concentrations from 0 to 4% NaCl for 24 h at 35°C.

The strains were then investigated for heat resistance (60°C), antibiotic susceptibility to eight antibiotics, and Caco-2 cell invasion efficiency.

S.

typhimurium NCCP10812 showed increased thermal resistance (P<0.05) after exposure to single NaCl concentrations.

A sequential increase of NaCl concentration decreased (P<0.05) the antibiotic sensitivities of S.

typhimurium NCCP10812 to chloramphenicol, gentamicin, and oxytetracycline.

NaCl exposure also increased (P<0.05) Caco-2 cell invasion efficiency of S.

enteritidis NCCP12243.

These results indicate that NaCl in food may cause increased thermal resistance, cell invasion efficiency, and antibiotic resistance of Salmonella.