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| Isolation and Identification of Escherichia coli O157:H7 from Cattle and Comparison of Their Acid Tolerance |
| FU Wenjing, JI Saisai, YU Jinlong, ZHANG Su, XU Yuanyuan, JIANG Yun |
| School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China |
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Abstract To investigate the variability of the tolerance of Shiga toxin-producing Escherichia coli O157:H7 to hydrochloric acid and lactic acid, suspected colonies were isolated from 309 fecal and beef samples and identified in this study. The isolates and another 14 strains collected for this study were detected for 4 major virulence genes (eae, hly, stx1, stx2) by multiplex polymerase chain reaction, and each of the Shiga toxin-producing strains with virulence genes was separately exposed to hydrochloric acid and lactic acid stress. The results showed that 8 isolates of E. coli O157 were identified and the prevalence of positive samples was 2.59%. The results of virulence genes showed that the stx1 and stx2 genes were detected in none of the 8 strains and the eae and hly genes were detected in 6 of them. The results of acid tolerance showed that the survival rates of 20 Shiga toxin-producing strains including the 6 strains and the other 14 above were all significantly decreased (P < 0.05) after treatment with hydrochloric acid or lactic acid for 2 h. However, this effect varied between strains, and the tolerance of the same strain to different acid treatments was different.
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GAO Tianqi, WANG Chao, WANG Lan, SHI Liu, CHEN Sheng, WU Wenjin, CHEN Lang, XIONG Guangquan. Isolation, Identification and Spoilage Ability of Dominant Spoilage Bacteria from Channel Catfish[J]. Meat Research, 2023, 37(3): 1-6. |
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2019, Vol. 33 
