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Food Qual Safet
    
Fate of enteric pathogens in different spinach cultivars cultivated in growth chamber and field systems
Marilyn C. Erickson,* Jye-Yin Liao,* Alison S. Payton,* Peter W. Cook,* Henk C. Den Bakker,* Jesus Bautista** and Juan Carlos Díaz Pérez**
*Department of Food Science and Technology, Center for Food Safety, University of Georgia, 1109 Experiment St., Griffin, GA 30223-1797, USA and **Department of Horticulture, University of Georgia, 2360 Rainwater Rd., Tifton, GA 31793-5766, USA
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Abstract  
Interactions between enteric pathogens and plant hosts have been shown to be multifaceted. This series of studies sought to expand our knowledge in this area and evaluate whether spinach cultivar selection may be used to curtail pathogen contamination and ultimately reduce microbiological risk associated with this crop. As a component to that assessment, potential antimicrobials that were constituents within spinach leaves were first analysed and found to be spatially nonuniform, being more concentrated on the outer edges of the leaves than in the centre of the leaves. Consequently, the entire foliage of a plant was sampled in subsequent studies examining the fate of Salmonella and Escherichia coli O157:H7 on seven cultivars of spinach. Cultivar did not affect the degree of Salmonella internalized into spinach tissue (P > 0.05); however, it appeared that those Salmonella that were internalized were transient residents as the percentage of plants containing this internalized pathogen dropped within 24 h. No relationship existed between antimicrobial levels (total phenols or antioxidant capacity) of the spinach cultivars and the prevalence of plants exhibiting Salmonella internalization or the persistence of Salmonella or E. coli O157:H7 after the plants had been sprayed with the pathogen. In both growth chamber and field studies, Salmonella was more resistant than E. coli O157:H7 to inactivation. Cultivar affected the persistence of both E. coli O157:H7 and Salmonella but the ranking for each pathogen’s survival on three of those cultivars differed suggesting the difficulty in finding one cultivar that would be inhospitable to multiple pathogens.


Key wordsspinach      cultivars      internalization      survival      phenols      antioxidant capacity      Salmonella      E. coli O157:H7.     
Published: 20 October 2018
Corresponding Authors: Marilyn C. Erickson, 1109 Experiment St., Griffin, GA 30223-1797. Telephone: 770-412-4742.     E-mail: mericks@uga.edu
Cite this article:

Marilyn C Erickson, Jye-Yin Liao, Alison S Payton, Peter W Cook, Henk C Den Bakker, Jesus Bautista, Juan Carlos Díaz Pérez. Fate of enteric pathogens in different spinach cultivars cultivated in growth chamber and field systems. Food Qual Safet, 2018, 2(4): 221-228.

URL:

http://www.zjujournals.com/fqs/10.1093/fqsafe/fyy020     OR     http://www.zjujournals.com/fqs/Y2018/V2/I4/221


大棚和田间培育的不同菠菜品种中肠道病原体情况

肠道病原体和植物宿主之间的相互作用是多方面的。一系列研究旨在拓展我们在该领域的知识,并评估是否可以通过菠菜品种选择来减少病原体污染并最终降低与该作物相关的微生物风险。作为评估组成部分,首先分析了作为菠菜叶中的潜在抗菌剂,发现它们在空间分布上是不均匀的,更多地集中在叶子的外缘而不是叶子的中心。因此,在随后的研究中对植物的整个叶子进行取样,检测7个菠菜品种的沙门氏菌和大肠杆菌O157:H7。发现品种不影响内化为菠菜组织的沙门氏菌程度(P> 0.05);然而,似乎内化的沙门氏菌是短暂存在,含有这种内化病原体的植物的百分比在24小时内下降。菠菜栽培品种的抗菌水平(总酚或抗氧化能力)与植物喷洒病原体后表现出沙门氏菌内化或沙门氏菌或大肠杆菌O157:H7持续存在的植物之间没有关系。在大棚和田间研究中,沙门氏菌比大肠杆菌O157:H7更能抵抗灭活。品种影响了大肠杆菌O157:H7和沙门氏菌的持久性,但每种病原体在其中三个品种中的存活率排序不一致,这表明难以找到一种不适合多种病原体的品种。

关键词: 菠菜,  栽培品种,  内化,  存活,  酚类,  抗氧化能力,  沙门氏菌,  大肠杆菌O157:H7 
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