Antibacterial activity and mode of action of totarol against in carrot juice.

Food contaminated with pathogenic bacteria such as (), represents a serious health risk to human beings. Totarol is an antibacterial novel phenolic diterpenes. In present study, the antibacterial activity of totarol against was investigated in a food system. The antibacterial activity of totarol was determined by measuring the zones of inhibition and minimum inhibitory concentrations (MICs). The MICs for strains were in the range of 2-4 μg/ml. The probable antibacterial mechanism of totarol was the alteration in cell membranes integrity and permeability, which leading to the leakage of cellular materials. The electric conductivity showed a time- and dose-dependent increasing manner, and we utilized totarol to induce the production of cytoplasmic β-galactosidase in . Scanning electron microscopy and transmission electron microscopy analysis further confirmed that cell membranes were damaged by totarol. The time-kill assay and detection of the kinetics of deactivation in situ indicated that totarol has good preservative activities in a food model. Totarol successfully inhibited development in carrot juice, at room temperature (25 °C) and in refrigerator (4 °C) respectively. Our works provided not only additional evidences in support of totarol being regarded as a natural antibacterial food preservative but also fundamental understanding on the mode of antibacterial action. It is necessary to consider that totarol will become a promising antibacterial additive for food preservative.