Optimization of Ozonated Water Treatment of Wild-Caught and Mechanically Peeled Shrimp Meat

ABSTRACT

Ozone is a USFDA and USDA approved food contact sanitizing agent and has been used in the seafood industry in both gaseous and dissolved forms to destroy bacteria. The wild harvest shrimp industry is the most economically important fishery in the U.S. Gulf of Mexico region, and in Louisiana the majority of the harvest is mechanically peeled and frozen. Dissolved ozone was measured in processing water at product application to study the optimization of ozonated water treatment for reducing microbial contamination of peeled shrimp meat. Shrimp samples were either sprayed or soaked in water with 1, 2, and 3 ppm dissolved ozone. Treatment times of 20, 40, and 60 seconds were investigated for all applications and concentrations. Similar volumes of water were applied for all treatments, and soaking showed greater bacterial reduction than spray treatments for all time and concentration combinations studied. Soaking in 3 ppm dissolved ozone for 40 s and 60 s showed the greatest reduction of total aerobic bacteria, and 60 s at 3 ppm resulted in the greatest reduction of Pseudomonas bacteria. Ozonated water treatment did not produce oxidation in the shrimp samples. The optimal treatment of soaking shrimp in 3 ppm dissolved ozone for 60 s will be used for further investigations of refrigerated shelf life extension and Listeria monocytogenes destruction in peeled shrimp meat.

KEYWORDS:

• Shrimp
• treatment
• ozone
• optimization