The Effect of Thermal Processing Schedules and Unit Operations on the Quality of Blue Crab (Callinectes sapidus) Meat

The effects of initial thermal processing, plant sanitation, and employee habits on the microbiological quality of blue crab (Callinectes sapidus) meat were determined in a commercial crab processing facility. Thermal processing was evaluated at 5, 7, and 8 minutes at 250ï °F for the destruction of microorganisms, including Listeria monocytogenes. F-values calculated indicated a sufficient reduction of L. monocytogenes at each processing time. Fresh picked crab meat was evaluated for microbial levels when exposed to ambient temperatures over a four hour period. It was found that time and temperature did not influence the microbial populations significantly except in the fourth hour. Plant sanitation was evaluated based on levels of adenosine triphosphate (ATP) and microbial counts. Areas found to have high levels of ATP typically had low microbial counts, thus suggesting that crab meat residual was the problem. The presence of Listeria species in the plant was determined using a commercial polyclonal antibody test. Listeria species were found under picking tables, on cooler doors, employees' aprons, and on several employees' hands. In a laboratory setting, an automated hand wash was compared with a manual hand wash for the removal of Listeria innocua, as a model for Listeria monocytogenes. It was found that a manual hand wash of 15 seconds was superior to an equal time automated wash. The microbial quality of crab meat was found to be affected by daily plant procedures, and could be changed by modifying procedures.