In the previous(108) studies, we have constructed a modified atmosphere condition by melted citrate solution with oyster shell powder. The modified atmosphere condition showed efficient inhibiting various aerobic microbial growths, including Acinetobacter lwoffii, Exiguobacterium spp., Pseudomonas poae, Psychrobacter celer, Shewanella putrefaciens, and psychrotrophic bacteria Psychrobacter spp., Microbacterium spp. and Pseudomonas spp.. Therefore the studies of natural preservative developments will keep going. In this year, the microbial suppressed efficiencies by the ice making water pretreated with the oyster shell calcinate or the ice block containing with the organic acid will screen.The addition of 2.5 g/L citric acid showed effectively inhibit microbial growths, including: Acinetobacter lwoffii, Pseudomonas poae, Exiguobacterium spp.. The addition of 5 g/L citric acid showed effectively inhibit microbial growths, including: Acinetobacter lwoffii, Pseudomonas poae, Exiguobacterium spp.. The addition of 0.3% calcined oyster shell powder showed inhibit microbial growths, but if the number of bacteria is too high, it can not be inhibited. In the ice melting test, the citric acid ice group and the shell powder sprinkled with citric acid ice group can significantly prolong the melting time of ice compared with the control group. Based on those results, the tablet or powder of natural preservative will be development with calcined oyster shell powder and food grade organic acid products. We expected to inhibit microbial growth, improve seafood quality by providing more hurdle technology of seafood for food safety especially focus on the cold chain of fisheries products.