Center for Food Safety, College of Agricultural and Environmental Sciences, University of Georgia, Griffin, GA 30223, United States of America.
USDA-ARS Environmental Microbial and Food Safety Laboratory, Henry A. Wallace Beltsville Agricultural Research Center, Beltsville, MD 20705, United States of America.
Int J Food Microbiol. 2020 Aug 2;326:108646. doi: 10.1016/j.ijfoodmicro.2020.108646. Epub 2020 Apr 23.
The effects of using contaminated seed and water on the persistence and internalization of Salmonella Newport in organic spinach cultivars- Lazio, Space, Emilia and Waitiki were studied. Seeds were contaminated by either immersing in a suspension of Salmonella and then sprouted or were sprouted in Salmonella contaminated water in the dark at 25 °C. After 5 days, germinated sprouts were analyzed for S. Newport population and internalization. Germinated sprouts were potted in soil and grown in a plant incubator for 4 weeks. Leaves, stems and roots were sampled for Salmonella population by plating on CHROMagar™. Plants surface-sterilized with chlorine were analyzed for internalized pathogen. Potting soil and water runoff were sampled for Salmonella after 4 weeks of plant growth. Contaminated seeds and irrigation water had S. Newport populations of 7.64±0.43 log CFU/g and 7.12±0.04 log CFU/ml, respectively. Sprouts germinated using contaminated water or seeds had S. Newport populations of 8.09±0.04 and 8.08±0.03 log CFU/g, respectively and had a Salmonella population that was significantly higher than other spinach tissues (P<0.05). Populations of S. Newport in leaves, stem and roots of spinach plants were as follows: contaminated seed- 2.82±1.69, 1.69±0.86, and 4.41±0.62 log CFU/ml; contaminated water- 3.56±0.90, 3.04±0.31, and 4.03±0.42 log CFU/ml of macerated tissue suspension, respectively. Internalization was observed in plants developing from contaminated seeds and in sprouts germinated using contaminated water. S. Newport populations of 2.82±0.70 log CFU/g and 1.76±0.46 log CFU/ml were recovered from soil and water runoff, respectively. The results indicate that contamination of spinach during germination can result in persistence, internalization and environmental reintroduction of Salmonella.
研究了使用受污染的种子和水对纽波特沙门氏菌在有机菠菜品种-拉齐奥、空间、艾米利亚和怀提基中的持久性和内化的影响。种子通过浸泡在沙门氏菌悬浮液中然后发芽，或者在 25°C 的黑暗中在受污染的水中发芽来污染。5 天后，分析发芽芽的沙门氏菌种群和内化情况。将发芽的芽盆栽在土壤中，并在植物培养箱中生长 4 周。通过在 CHROMagar™上平板分析叶片、茎和根中的沙门氏菌种群。用氯对植物表面进行消毒，然后分析内化的病原体。在植物生长 4 周后，对盆栽土壤和水径流进行沙门氏菌采样。污染的种子和灌溉水中的沙门氏菌种群分别为 7.64±0.43 log CFU/g 和 7.12±0.04 log CFU/ml。使用受污染的水或种子发芽的芽的沙门氏菌种群分别为 8.09±0.04 和 8.08±0.03 log CFU/g，明显高于其他菠菜组织（P<0.05）。菠菜植物叶片、茎和根中的沙门氏菌种群如下：污染种子-2.82±1.69、1.69±0.86 和 4.41±0.62 log CFU/ml；污染水-3.56±0.90、3.04±0.31 和 4.03±0.42 log CFU/ml 的组织匀浆。在受污染种子发育的植物和使用受污染水发芽的芽中观察到内化。从土壤和水径流中分别回收了 2.82±0.70 log CFU/g 和 1.76±0.46 log CFU/ml 的沙门氏菌种群。结果表明，发芽期间菠菜的污染会导致沙门氏菌的持久性、内化和环境再引入。
