Thermal inactivation of listeria monocytogenes in crab meat

Abstract

Listeria monocytogenes is an important bacterial pathogen in seafood products, but limited information is currently available on the thermal resistance of relevant isolates in seafood. Thermal inactivation studies were undertaken (i) to provide much needed thermal inactivation data for L. monocytogenes in crab meat and (ii) to investigate whether tryptone soya broth (TSB) is representative of crab meat in thermal inactivation studies involving L. monocytogenes. D-values were obtained for a cocktail of two crab isolates (serotypes 1/2a and 4b) at 50, 55, and 608C. In crab meat, D-values were 174.4, 28.2, and 1.6 min, respectively. Similar D-values of 176.4, 28.8, and 1.4 min were obtained in TSB. The corresponding z-values were 4.98C (crab meat) and 4.88C (TSB), respectively. The conclusions were that (i) current pasteurization conditions (e.g., 708C for 2 min) would achieve complete destruction of any L. monocytogenes present in crab meat and (ii) TSB could be used as a model matrix for assessing the thermal inactivation of L. monocytogenes in crab meat.