牡蛎是世界性的水产养殖物种，也是我国产量最高的经济贝类。当前，牡蛎养殖海域仍然存在各类水质污染问题，影响牡蛎品质和食品安全，尤其是作为高端食材的生食牡蛎，水产品安全和产品品质无法保障。为降低牡蛎食用风险、提高牡蛎产品价值，满足人们对生食牡蛎的市场需求，本研究通过循环水净化工艺，摸清了温度、盐度、水交换率、紫外和臭氧等对牡蛎净化的影响规律，探索了生食牡蛎净化工艺技术和参数，取得的主要研究结果如下：

（1）在本研究设计的循环水净化系统中，温度、盐度和水交换率对牡蛎体内菌落总数的净化效果有显著性影响（P < 0.05）；温度和水交换率对牡蛎体内大肠菌群的净化效果有显著性影响（P < 0.05）；在温度15 ~ 25 ℃、盐度15 ~ 30和水交换率2 ~ 12 次/h条件下，经48 h净化后，牡蛎体内菌落总数 ≤ 4 log CFU/g，大肠菌群 ≤ 10 CFU/g，副溶血性弧菌未检出，达到生食要求。

（2）在本研究设计的循环水净化系统中，紫外辐照剂量6.22 ~ 9.33 J/cm³条件下，经48 h净化后，牡蛎体内菌落总数 ≤ 4 log CFU/g，大肠菌群 ≤ 10 CFU/g，副溶血性弧菌未检出，达到生食要求。紫外辐照剂量对牡蛎体内菌落总数的净化效果有显著性影响（P < 0.05）。但紫外辐照剂量达到一定（6.22 J/cm³）时，继续增加紫外辐照剂量对牡蛎体内菌落总数和大肠菌群的净化效率无显著性影响。

（3）在本研究设计的循环水净化系统中，臭氧流量1 L/min ，间隔6 h 曝气20 ~ 30 min的条件下，经36 h净化后，牡蛎体内菌落总数 ≤ 4 log CFU/g，大肠菌群 ≤ 10 CFU/g，副溶血性弧菌未检出，达到生食要求。间歇式臭氧曝气对牡蛎体内菌落总数和大肠菌群的净化效果有显著性影响（P < 0.05）。臭氧对大肠菌群的净化效果优于菌落总数的净化效果；间歇式臭氧曝气方式在较高浓度（1.41 mg/L）下不影响牡蛎的正常代谢，并有较好的净化效果。

（4）根据上述研究结果，从净化效率和净化成本考虑，建议净化温度为20 ~ 25 ℃，净化盐度为20 ~ 25，净化水交换率为4 次/h，紫外辐照剂量3.11 J/cm³，臭氧剂量为0.97 ~ 1.08 mg/L。

Oysters are a worldwide aquaculture species and the economical shellfish with the highest production in my country. At present, there are still various water pollution problems in oyster farming sea areas, which affect the quality and food safety of oysters. Especially for raw oysters, which are high-end ingredients, the safety and quality of aquatic products cannot be guaranteed. In order to reduce the risk of eating oysters, improve the value of oyster products, and meet people's market demand for raw oysters, this study uses the circulating water depuration process to research the influence laws of temperature, salinity, water exchange rate, ultraviolet and ozone on the depuration of oysters were found out and explore the technology and parameters mechanism of depuration of raw oysters. The main research results obtained are as follows:

(1) In the circulating water depuration system designed in this study, temperature, salinity and water exchange rate had significant effects on the depuration effect of the Total Viable count in oysters (P < 0.05); Temperature and water exchange rate had a significant effect on the depuration effect of the Coliform in oysters (P < 0.05). Under the conditions of temperature 15 ~ 25 ℃, salinity 15 ~ 30 and water exchange rate 2 ~ 12 times/h, after 48 h depuration, the Total Viable count in the oyster was ≤ 4 log CFU/g, the Coliform in the oyster was ≤ 10 CFU/g, and Vibrio parahaemolyticus was not detected, meeting the requirements of raw food.

(2) In the circulating water depuration system designed in this study, under the conditions of UV irradiation dose of 6.22 ~ 9.33 J/cm3 , after 48 h depuration, the Total Viable count in the oyster was ≤ 4 log CFU/g, the Coliform in the oyster was ≤ 10 CFU/g, and Vibrio parahaemolyticus was not detected, meeting the requirements of raw food. UV irradiation dose had a significant effect on the depuration effect of the Total Viable count in oysters (P < 0.05). When the UV irradiation dose reached a certain level (6.22 J/cm3), continuing to increase the  UV irradiation dose had not a significant effect on the depuration efficiency of the Total Viable count and the Coliform.

(3) In the circulating water depuration system designed in this study, under the conditions of ozone flow rate of 1L/min and aeration of 20 ~ 30min at intervals of 6 h, after depuration for 36 h, the Total Viable count in the oyster was ≤ 4 log CFU/g, the Coliform in the oyster was ≤ 10 CFU/g, and Vibrio parahaemolyticus was not detected, meeting the requirements of raw food. Intermittent ozone aeration had a significant effect on the Total Viable count and the Coliform in oysters (P < 0.05). The depuration effect of ozone on the Coliforms was better than that of the Total Viable count. Intermittent ozone aeration did not affect the normal metabolism of oysters at a higher concentration (1.41 mg/L), and had a better depuration effect.

(4) According to the above research results, considering the depuration efficiency and depuration cost, it is recommended that the depuration temperature be 20 ~ 25 ℃, the depuration salinity should be 20 ~ 25, the depuration water exchange rate should be 4 times/h, and the UV radiation dose should be 3.11 J/ cm3 , the ozone dose is 0.97 ~ 1.08 mg/L

目 录

摘 要

Abstract

目 录

第一章 绪论

1.1 生食牡蛎现状

1.2 贝类净化研究现状

1.2.1 净化系统

1.2.2 贝类净化技术

1.2.4 影响贝类净化的环境参数

1.3 研究的内容和目的

1.4 技术路线

第二章 温度、盐度和水交换率对牡蛎净化的影响

2.1引言

2.2材料与方法

2.2.1 实验牡蛎

2.2.2 实验系统

2.2.3 实验方法

2.2.4 微生物指标测定

2.2.5 数据处理

2.3结果与分析

2.3.1 温度对牡蛎净化的影响

2.3.2 盐度对牡蛎净化的影响

2.3.3 水交换率对牡蛎净化的影响

2.4讨论

2.4.1 温度对牡蛎净化的影响

2.4.2 盐度对牡蛎净化的影响

2.4.3 水交换率对牡蛎净化的影响

2.5小结

第三章 紫外辐照剂量对牡蛎净化的影响

3.1 引言

3.2 材料与方法

3.2.1 实验牡蛎

3.2.2 实验系统

3.2.3 实验方法

3.2.4 微生物指标测定

3.2.5 数据处理

3.3 结果与分析

3.3.1 紫外辐照剂量对牡蛎净化的影响

3.4讨论

3.4.1 紫外对牡蛎净化的影响

3.4.2 净化时间的选择

3.5小结

第四章 间歇式臭氧曝气对牡蛎净化的影响

4.1引言

4.2材料与方法

4.2.1 实验牡蛎

4.2.2 实验系统

4.2.3 实验方法

4.2.4 微生物指标测定

4.2.5 数据处理

4.3结果与分析

4.3.1 间歇式臭氧曝气对牡蛎净化的影响

4.3.2 间歇式臭氧曝气后水体中臭氧浓度

4.4讨论

4.4.1 臭氧对大肠菌群净化优势

4.4.2 间歇式臭氧曝气的优势

4.5小结

第五章 总结与展望

5.1 研究结论

5.2 展望