Synergistic effect of cinnamaldehyde on the thermal inactivation of Listeria monocytogenes in ground pork

The aim of this study was to statistically evaluate the effect of a naturally food-derived cinnamaldehyde on the thermal inactivation of Listeria monocytogenes in ground pork. This study combined four concentrations of cinnamaldehyde (0, 0.1, 0.5, and 1.0% vol/wt) and four temperatures (55, 60, 65, and 70 celcius) to predict the thermal inactivation curves of L. monocytogenes. The Weibull model successfully described the primary thermal inactivation using the Integrated Pathogen Modeling Program. These results statistically proposed that the cinnamaldehyde supplementation in ground pork attenuates the thermo-tolerance of L. monocytogenes. The time for achieving a 5-log(10) reduction of L. monocytogenes declined from 28.14 to 17.35 min at 55 celcius when the ground pork sample was supplemented by 1% cinnamaldehyde, while the time declined from 1.95 to 0.34 min at 70 celcius. Thereafter, based on the 5.0-log(10) lethality, secondary models were fitted by a selected polynomial model. The transmission electron microscopy revealed that cinnamaldehyde causes serious damage to membrane integrity and increases the occurrence of cell membrane rupture and leakage of cytoplasmic content under thermal treatment. Our model represents a mathematical tool that will help meat-product manufacturers to improve the efficacy of thermal processing ground pork supplemented with cinnamaldehyde.