Submitted to: Food Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/17/2016
Publication Date: 8/20/2016
Citation: Li, C., Huang, L., Hwang, C. 2016. Effect of temperature and salt on thermal inactivation of Listeria monocytogenes in Salmon Roe. Food Control. doi: 10.1016/j.foodcont.2016.08.027.
Interpretive Summary: Salmon roe is a high-value seafood product that can be contaminated with Listeria monocytogenes. Once contaminated, a disinfection technology is needed to render salmon roe free of the pathogen. This study was conducted to evaluate the effect of temperature and salt on thermal resistance of L. monocytogenes in salmon roe. The results from this study can be used to design effective thermal processes to inactivate L. monocytogenes in salmon roe.
Technical Abstract: Listeria monocytogenes is a potentially fatal foodborne pathogen that can be found in ready-to-eat seafood products, such as fresh salmon roe. Once contaminated, salmon roe must be decontaminated prior to human consumption. This study was conducted to determine the thermal inactivation kinetics of L. monocytogenes in raw salmon roe as affected by bacterial strain, temperature, and salt concentration. Three different strains of L. monocytogenes, including serotype 4b (F2365), 1/2b (F4260), and 1/2a (V7) was individually inoculated to salmon roe supplemented with salt (0 - 4.5%), and heated under different temperatures of 57.5, 60.0, 62.5, and 65.0 degrees C to evaluate the survival of the bacterium during heating and determine the D-values. Results showed that the thermal resistance (log D) of L. monocytogenes was significantly affected by bacterial strain, temperature, and salt and by their interactive effects, with strain F2365 being the most heat-resistant among all three strains tested. Salt added to salmon roe significantly increased the thermal resistance of the bacteria. For L. monocytogenes F2365, the z value of the bacterium in salmon roe was 5.99 degrees C, and its heat resistance increased with the level of salt in a linear manner. The results of kinetic analysis and the models obtained in this study may be used by the seafood industry to develop proper thermal processes to eliminate L. monocytogenes in raw salmon roe and to ensure microbial safety and prevent foodborne illness.