Artisanal vegetable fermentations are regaining popularity in industrialized countries, but they could be prone to contamination with foodborne pathogens. By simulating home or small-scale restaurant fermentations, we evaluated the microbiological safety of spontaneous carrot juice fermentations. Raw carrot juice was spiked with Listeria monocytogenes, Salmonella enterica subsp. enterica Typhimurium and Escherichia coli O157:H7, and the microbial dynamics were followed throughout the entire fermentation process by cultivation and amplicon sequencing. In addition, the behavior of these pathogens was also monitored after addition of raw cucumber juice and storage under refrigerated conditions to mimic post-contamination issues. Although the numbers of the pathogens increased during the first phase of the fermentation, the pathogens were not able to persist throughout the fermentation. Their numbers fell below the detection limit after 8 days of fermentation at 20 °C. Further investigation using amplicon sequencing also showed that there was no major impact on the general microbial dynamics of the spontaneous carrot juice fermentation. This indicates that the artisanal carrot juice fermentation is a robust process which resists the persistence of pathogens. More caution is needed however when mixing the final fermented product with a raw juice. When simulating pathogen post-contamination, both Salmonella enterica and Escherichia coli were able to survive in the refrigerated fermented juice up to 10 days after the fermentation. Listeria monocytogenes was detected up to 8 days in the refrigerated juice. Pasteurization of the raw juice before adding it to the fermented product is thus recommended.

手工蔬菜发酵在工业化国家中正逐渐流行，但是它们很容易被食源性病原体污染。通过模拟家庭或小型餐厅的发酵，我们评估了自发胡萝卜汁发酵的微生物学安全性。未加工的胡萝卜汁掺入单核细胞增生李斯特菌，肠炎沙门氏菌亚种。肠道鼠伤寒沙门氏菌和大肠埃希氏菌在整个发酵过程中，通过培养和扩增子测序来跟踪O157：H7和微生物动力学。此外，在添加生黄瓜汁并在冷藏条件下储存以模仿污染后问题后，还对这些病原体的行为进行了监测。尽管在发酵的第一阶段中病原体的数量增加了，但是病原体不能在整个发酵过程中持续存在。在20°C发酵8天后，它们的数量降至检测极限以下。使用扩增子测序的进一步研究还表明，对自发胡萝卜汁发酵的总体微生物动力学没有重大影响。这表明，手工胡萝卜汁的发酵是抵抗病原体持久性的强大过程。但是，将最终发酵产品与原汁混合时，需要格外小心。模拟病原体后污染时，两者肠炎沙门氏菌和大肠埃希菌在发酵后的冷冻果汁中能够存活多达10天。在冷藏果汁中检测到最多8天的单核细胞增生李斯特菌。因此，建议在将生果汁添加到发酵产品中之前进行巴氏杀菌。