| 摘要: |
| 为了明确牡蛎养殖过程中食源性致病菌含量的周年变化规律及其影响因素，本研究采用平板涂布法并结合PCR技术，对海南地区香港牡蛎(Crassostrea hongkongensis)养殖水体及其不同组织中的菌落总数和五种食源性细菌含量进行定量检测，并分析了其与环境相关性。结果表明：(1)大肠杆菌(Escherichia coli)、副溶血弧菌(Vibrio parahaemolyticus)、创伤弧菌(Vibrio vulnificus)和单增李斯特氏菌(Listeria monocytogenes)是香港牡蛎体内的主要食源性菌，其最高含量分别为6.3×10? CFU/g、2.9×10? CFU/g、6.1×10? CFU/g和1.4×10? CFU/g；各组织中上述细菌含量均显著高于养殖水体。沙门氏菌(Salmonella)仅在个别月份部分组织中被检出(7月份鳃和9月消化腺中含量分别为2.3×103和2.1×104 CFU/g)。(2)菌落总数及4种主要食源性致病菌的含量均呈现明显的季节性波动，且养殖水体与牡蛎各组织的变动规律较为一致，均在2~3月和8~10月出现两个含量高峰。(3) 香港牡蛎鳃和外套膜中的食源性致病菌含量最高、其次为消化腺和闭壳肌，性腺中含量最低。(4)环境因子与食源性致病含量之间存在呈现一定的弱相关性。养殖水体中食源致病含量与盐度、pH呈正相关，与温度和叶绿素a浓度呈负相关性；而香港牡蛎鳃和外套膜中大肠杆菌、创伤弧菌和副溶血弧菌含量则与温度和水体叶绿素a浓度呈正相关。本研究为揭示牡蛎食源性致病菌的周年动态变化及食品安全风险预警提供了科学依据。 |
| 关键词: 香港牡蛎 食源性致病菌 环境因子 相关性 周年变化 |
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| 基金项目:海南省重点研发计划项目(ZDYF2023XDNY032, ZDYF2024SHFZ139); 三亚科技“繁星”专项项目(2024KJFX019) |
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| Annual variation of foodborne bacteria in Hong Kong oysters (Crassostrea hongkongensis) and their aquaculture water and its correlation with environmental factors |
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Hu Qingsong, Yang Wenhong, Bao Lingxiang, Hong Xin, Sun Hao, Zhou Duyuan, Liu Chunsheng
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Hainan University
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| Abstract: |
| To clarify the annual variation of foodborne bacterial loads and their influencing factors during oyster cultivation, this study quantified the total bacterial count and the abundances of five foodborne bacteria in both aquaculture water and various tissues of Crassostrea hongkongensis in the Hainan province using plate counting combined with PCR technology. The correlations between bacterial levels and environmental factors were also analyzed. The results showed that: (1) Escherichia coli, Vibrio parahaemolyticus, Vibrio vulnificus, and Listeria monocytogenes were the dominant foodborne bacteria in Hong Kong oysters, with maximum concentrations of 6.3×10? CFU/g, 2.9×10? CFU/g, 6.1×10? CFU/g, and 1.4×10? CFU/g, respectively. The bacterial levels in all oyster tissues were significantly higher than those in the aquaculture water. Salmonella was only detected in specific months, with levels of 2.3×103 CFU/g in gills in July and 2.1×10? CFU/g in digestive gland in September. (2) Both the total bacterial count and the four dominant foodborne bacteria exhibited clear seasonal fluctuations, with consistent variation patterns observed between aquaculture water and oyster tissues. Two abundance peaks occurred in February–March and August–October. (3) The highest bacterial loads were found in the gills and mantle, followed by the digestive gland and adductor muscle, while the gonad showed the lowest levels. (4) Weak correlations were observed between environmental factors and foodborne bacterial concentrations. In aquaculture water, bacterial levels were positively correlated with salinity and pH, but negatively correlated with temperature and chlorophyll a concentration. In contrast, E. coli, V. vulnificus, and V. parahaemolyticus in the gills and mantle of oysters were positively correlated with temperature and chlorophyll a concentration in water. This study provides a scientific basis for understanding the annual dynamics of foodborne bacteria in oysters and early warning of related food safety risks. |
| Key words: Crassostrea hongkongensis foodborne bacteria environmental factors correlation annual variation |