Low Temperature Growth and Thermal Inactivation of Listeria monocytogenes in Precooked Crawfish Tail Meat1

Abstract

Growth of Listeria monocytogenes in precooked crawfish tail meat at 0, 6, and 12°C was determined. Thermal death times were also determined. Growth curves for L. monocytogenes revealed that little multiplication was observable for the entire storage time of 20 d at 0°C. At 6 and 12°C, exponential growth began immediately with no observed lag phase. Generation times of 72.2, 17.0, and 6.9 h were calculated at 0, 6, and 12°C, respectively. Observed D values at 55, 60, and 65°C were 10.23, 1.98, and 0.19 min, respectively. The z value for L. monocytogenes in precooked crawfish tail meat was calculated to be 5.5°C. Results from this study indicate that a refrigeration temperature of 6°C (42.8°F) will support growth of L. monocytogenes and short-term temperature abuse at 12°C will induce very rapid growth of the organism on crawfish tail meat. Thermal treatment values from this study can be used to establish postpicking heat treatments that would eliminate L. monocytogenes from packaged crawfish tail meat prior to retail sale.