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United States Department of Agriculture

Agricultural Research Service

Research Project: ALTERNATIVE FOOD PROCESSING TECHNOLOGIES

Location: Food Safety and Intervention Technologies

Title: Incidence and inactivation of Listeria spp. on frozen shrimp

Authors
item Rajkowski, Kathleen
item Sommers, Christopher
item Antenucci, Rachel -
item Mills, Brittany -
item Scullen, O
item Cassidy, Jennifer
item Sites, Joseph

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 22, 2012
Publication Date: July 22, 2012
Citation: Rajkowski, K.T., Sommers, C.H., Antenucci, R., Mills, B., Scullen, O.J., Cassidy, J.M., Sites, J.E. 2012. Incidence and inactivation of Listeria spp. on frozen shrimp [abstract]. IAFP Meeting. July 22-25, 2012, Providence, RI. 1:1.

Technical Abstract: Foodborne illness outbreaks occasionally occur as a result of microbiologically contaminated crustaceans, including shrimp. Foodborne pathogens occasionally found on shrimp include Listeria monocytogenes, Salmonella spp., Staphylococcus aureus, and Vibrios. In this study the microbiological quality of frozen raw shrimp was investigated. The use of 3 intervention technologies to inactivate Listeria on shrimp was also investigated. Thirty two frozen shrimp samples, both imported and domestic, were tested for aerobic plate counts (APC at 22 and 37 deg C), coliforms, and Enterbacteriacea, using USDA Food Safety Inspection Service (FSIS) Microbiological Laboratory Guide procedures, as now FSIS is responsible for testing some aquaculture products. FSIS procedures were also used to determine the incidence of L. monocytogenes (LM), Salmonella spp., S. aureus on the shrimp samples. The average APCs were approximately 4.06 and 3.64 log CFU/g at 22 and 37 deg C, while coliforms and enteric bacteria were approximately 0.02 and 1.43 log CFU/g, respectively. None of the samples tested positive for Salmonella spp., S. aureus using the BAX-TM polymerase chain reaction detection. 7/32 tested positive for Listeria spp., and viable LM was recovered from 4 (12.5%) of the 32 shrimp samples. Three intervention technologies, ultraviolet light (254 nm, 0.5 to 2.0 J/cm2), ozonated water (2 ppm, 0.25 to 2 min), and gamma radiation (1.0 to 5.0 kGy) were used to inactivate L. innocua, a LM surrogate, surface inoculated onto shrimp in a pilot plant setting. Ultraviolet light (2.0 J/cm2) inactivated approximately 0.4 log CFU/g, ozonated water (2 ppm, 2 min) inactivated 1.5 log CFU/g, and 5 kGy gamma radiation inactivated > 5 log CFU/g of L. innocua, respectively. Additional research is needed to determine the effect of commonly used intervention technologies on the detection and isolation of foodborne pathogens in seafood products.

Last Modified: 10/20/2014