Antibacterial effect of ultrasound and β-citronellol against Listeria monocytogenes and its application in carrot preservation

•US combined with β-citronellol (US + CT) had a synergistic effect on the inactivation of Listeria monocytogenes.•US + CT caused an increase in ROS levels and extracellular MDA content of L. monocytogenes.•US + CT severely disrupted cell membrane integrity, permeability and cell morphology.•US + CT significantly reduced the populations of L. monocytogenes on the carrot surface.•US + CT did not affect the color of the carrots but reduced the moisture and hardness of carrots.