Detert Katharina, Schmidt Herbert
Department of Food Microbiology and Hygiene, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstraße 28, 70599 Stuttgart, Germany.
Microorganisms. 2023 Aug 12;11(8):2072. doi: 10.3390/microorganisms11082072.
In the current study, we demonstrate that O104:H4 strain C227/11Φcu, a derivative of the 2011 enterohemorrhagic/enteroaggregative (EHEC/EAEC) outbreak strain, migrated into the edible portion of lamb's lettuce plants upon contamination of the surrounding soil. Seeds were surface-sterilized and cultivated on Murashige-Skoog agar or in autoclaved agricultural soil. Migration into the edible portions was investigated by inoculating the agar or soil close to the plants with 10 colony-forming units (CFU). The edible parts, which did not come into contact with the contaminated medium or soil, were quantitatively analyzed for the presence of bacteria after 2, 4 and 8 weeks. Strain C227/11Φcu could colonize lamb's lettuce when contamination of medium or soil occurs. The highest recovery rate (27%) was found for lettuce cultivated in agar, and up to 1.6 × 10 CFU/g lettuce was detected. The recovery rate was lower for the soil samples (9% and 13.5%). Although the used contamination levels were high, migration of C227/11Φcu from the soil into the edible parts was demonstrated. This study further highlights the risk of crop plant contamination with pathogenic upon soil contamination.
在当前研究中，我们证明了O104:H4菌株C227/11Φcu（2011年肠出血性/肠聚集性（EHEC/EAEC）暴发菌株的衍生物）在周围土壤受到污染时会迁移到羊生菜植株的可食用部分。种子进行表面灭菌后，在Murashige-Skoog琼脂培养基上或在经高压灭菌的农业土壤中培养。通过在植株附近的琼脂或土壤中接种10个菌落形成单位（CFU）来研究细菌向可食用部分的迁移情况。在2周、4周和8周后，对未与受污染培养基或土壤接触的可食用部分进行细菌定量分析。当培养基或土壤受到污染时，C227/11Φcu菌株能够在羊生菜上定殖。在琼脂培养基中培养的生菜回收率最高（27%），检测到的生菜中细菌含量高达1.6×10 CFU/g。土壤样本的回收率较低（9%和13.5%）。尽管使用的污染水平很高，但仍证明了C227/11Φcu菌株能从土壤迁移到可食用部分。这项研究进一步凸显了土壤污染时致病原污染作物的风险。
