Purpose: To evaluate the antimicrobial efficacy of NEO water on Vibrio spp. in raw oysters
Methods: Fresh Eastern oysters were harvested and transported to the Laboratory on ice. Upon arrival at the lab, oysters were kept in 3.5% artificial seawater for a short period of depuration. NEO water (pH: 6.75; oxidation-reduction potential (ORP): 820.2; free chlorine: 98 ppm) was prepared by the food safety engineering lab at University of Georgia and tap water was used to make NEO water dilutions. Full NEO water, 1:1 and 1:4 dilution between NEO water and tab water were established as 3 treatments. The pH, ORP, and free chlorine were measured at 0, 3, 6, 12, and 24 h. Population of Vibrio spp. in oyster was determined by thiosulfate citrate bile salts sucrose (TCBS) agar plating at 0, 2, and 5 h.
Results: The result shows that free chlorine reduced significantly (p<0.05) by the preservation of oyster after 3 hours while free chlorine of NEO water without oyster remained stable. Significant difference (P<0.05) was also observed in ORP and pH value in NEO water with oyster in all three treatments and both parameters were changing dramatically (p<0.05) when free chlorine value dropped near 0. While Vibrio spp. population remained stable among all sampling points, significant difference (about 1 log)(P<0.05) was detected between 2 h and 5 h in treatment of 1:4 diluted NEO as free chlorine dropped to 0 after 3 hours.
Significance: Result demonstrates the potential of using NEO water to control Vibrio spp. in oysters during depuration.