Liu X, Sun H H, Liu L S, Wang X, Li S T, Zhang X H, Li L Q, Bai L
Key laboratory of Food Safety Risk Assessment of National Health Commission, China National Centre for Food Safety Risk Assessment, Beijing 100021, China.
Irradiation Preservation Key Laboratory of Sichuan Province, Chengdu Institute of Food Inspection, Chengdu 610045, China.
Zhonghua Yu Fang Yi Xue Za Zhi. 2025 Apr 6;59(4):443-450. doi: 10.3760/cma.j.cn112150-20241030-00862.
To analyze the contamination characteristics and pathogenic potential of (LM) in pre-packaged and refrigerated ready-to-eat cooked meat products in Chengdu City. From September 2022 to May 2023, pre-packaged and refrigerated ready-to-eat cooked meat products were collected from six districts and counties in Chengdu City. Qualitative and quantitative determination of LM was performed on these samples. Whole genome sequencing was carried out on the isolated strains. Different ST strains were selected for cell adhesion and invasion experiments. The results were expressed as adhesion rate and invasion rate. One-way ANOVA was used for comparison between groups, and the Dunnett -test was used for pairwise comparison. A total of 145 samples were collected, and LM was detected and isolated in 29 samples. The total detection rate was 20.00%, and the detection rate of braised pork was the highest (68.18%). The contamination level of LM in 9 samples (31.03%) was greater than 100.00 MPN/g. The 29 strains of belonged to 7 STs, including ST 3 (27.59%), ST 8 (17.24%) and ST 87 (13.79%). The strain of ST 87 carried pathogenicity islands 4 (LIPI-4), which was a highly virulent strain. The medium and high virulence strains accounted for 79.31%. Some moderately virulent and highly virulent strains of ST 8 and ST 87 were closely related to clinical patient strains. Some LM isolates of the same ST type had little SNP differences (1-6) in the same manufacturer at different stages. In vitro cell experiments showed that the highly virulent strain ST 87 had the strongest adhesion and invasion ability towards Caco-2 cells. The pre-packaged and refrigerated cooked meat products have a high contamination rate. Some samples have high contamination levels and carry medium and high virulence strains, posing potential health risks to human beings. LM residues continue to persist in some manufacturers' production and processing stages.
分析成都市预包装冷藏即食熟肉制品中李斯特菌（LM）的污染特征及致病潜力。2022年9月至2023年5月，从成都市六个区县采集预包装冷藏即食熟肉制品。对这些样品进行LM的定性和定量测定。对分离菌株进行全基因组测序。选择不同的ST菌株进行细胞黏附和侵袭实验。结果以黏附率和侵袭率表示。采用单因素方差分析进行组间比较，Dunnett检验进行两两比较。共采集145份样品，29份样品检测到并分离出LM。总检出率为20.00%，其中卤猪肉检出率最高（68.18%）。9份样品（31.03%）中LM的污染水平大于100.00 MPN/g。29株LM属于7种ST型，包括ST3（27.59%）、ST8（17.24%）和ST87（13.79%）。ST87菌株携带致病岛4（LIPI-4），为高毒力菌株。中高毒力菌株占79.31%。ST8和ST87的一些中度毒力和高毒力菌株与临床患者菌株密切相关。同一ST型的一些LM分离株在同一厂家不同阶段的单核苷酸多态性差异很小（1-6个）。体外细胞实验表明，高毒力菌株ST87对Caco-2细胞的黏附和侵袭能力最强。预包装冷藏熟肉制品污染率较高。部分样品污染水平高，携带中高毒力菌株，对人类健康构成潜在风险。LM残留持续存在于部分厂家的生产加工环节。
