Purpose: There is little data on the use of commercial or pilot-scale equipment and processes to quantify the effect of freezing on foodborne pathogen survival. The purpose of this study is to evaluate the effect of cryogenic freezing and gamma radiation on the survival of foodborne pathogens in crawfish tail meat.
Methods: In this study the use of cryogenic freezing (CF) and gamma radiation (GR) were evaluated for their ability to inactivate the foodborne pathogens E. coli O157:H7, Listeria monocytogenes, Salmonella spp., Staphylococcus aureus, and Vibrio spp. inoculated on partially cooked crawfish tail meat. The final inoculums level on the crawfish tail meat was 6 – 7 log CFU/gm.
Results: CF (-59 °C, 3 min) resulted in 0.85, 0.71, and 0.80 log reductions of the Gram-negative pathogens E. coli O157:H7, Salmonella spp., and Vibrio spp., respectively, following freezing and one week storage at -20 °C. CF had no effect on the viability of L. monocytogenes or S. aureus (Gram positive). D10 values (the radiation dose needed to inactivate one log of microorganism) of the foodborne pathogens which were irradiated following one week frozen storage were 0.81, 0.58, 0.50, 0.49, and 0.36 kGy for L. monocytogenes, S. aureus, Vibrio spp., Salmonella spp., and E. coli O157:H7, respectively. The radiation D10 of background microflora in non-inoculated frozen tail meat was 1.58 and 1.64 kGy for mesophilic and psychrotrophic bacteria, respectively.
Significance: This research provides the seafood and radiation processing industries the necessary information to inactivate foodborne pathogens in crawfish tail meat.