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Woodford L, Fellows R, White HL, Ormsby MJ, Quilliam RS. Salmonella Typhimurium and Vibrio cholerae can be transferred from plastic mulch to basil and spinach salad leaves. Heliyon 2024; 10:e31343. [PMID: 38818200 PMCID: PMC11137414 DOI: 10.1016/j.heliyon.2024.e31343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Revised: 05/14/2024] [Accepted: 05/14/2024] [Indexed: 06/01/2024] Open
Abstract
Plastic pollution is increasingly found in agricultural environments, where it contaminates soil and crops. Microbial biofilms rapidly colonise environmental plastics, such as the plastic mulches used in agricultural systems, which provide a unique environment for microbial plastisphere communities. Human pathogens can also persist in the plastisphere, and enter agricultural environments via flooding or irrigation with contaminated water. In this study we examined whether Salmonella Typhimurium and Vibrio cholerae can be transferred from the plastisphere on plastic mulch to the surface of ready-to-eat crop plants, and subsequently persist on the leaf surface. Both S. Typhimurium and V. cholerae were able to persist for 14 days on fragments of plastic mulch adhering to the surface of leaves of both basil and spinach. Importantly, within 24 h both pathogens were capable of dissociating from the surface of the plastic and were transferred onto the surface of both basil and spinach leaves. This poses a further risk to food safety and human health, as even removal of adhering plastics and washing of these ready-to-eat crops would not completely remove these pathogens. As the need for more intensive food production increases, so too does the use of plastic mulches in agronomic systems. Therefore, there is now an urgent need to understand the unquantified co-pollutant pathogen risk of contaminating agricultural and food production systems with plastic pollution.
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Affiliation(s)
- Luke Woodford
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Rosie Fellows
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Hannah L. White
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Michael J. Ormsby
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Richard S. Quilliam
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
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2
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Deng W, Gibson KE. Microgreen Variety Impacts Leaf Surface Persistence of a Human Norovirus Surrogate. FOOD AND ENVIRONMENTAL VIROLOGY 2023; 15:82-88. [PMID: 36151506 DOI: 10.1007/s12560-022-09536-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 09/15/2022] [Indexed: 06/16/2023]
Abstract
Human norovirus (HuNoV) is a pathogenic agent that is frequently associated with foodborne disease outbreaks linked to fresh produce. Within microgreen production systems, understanding of virus transmission routes and persistence is limited. To investigate virus persistence on microgreen leaf surfaces, this study mimicked virus contaminations caused during microgreen handling by farm workers or during overhead irrigation with contaminated water. Specifically, approximately 5 log PFU of Tulane virus (TV)-a HuNoV surrogate-was inoculated on sunflower (SF) and pea shoot (PS) microgreen leaves at 7-day age. The virus reduction on SF was significantly higher than PS (p < 0.05). On day 10, total TV reduction for SF and PS were 3.70 ± 0.10 and 2.52 ± 0.30 log PFU/plant, respectively. Under the environmental scanning electron microscope (ESEM) observation, the leaf surfaces of SF were visually smoother than PS, while their specific effect on virus persistence were not further characterized. Overall, this study revealed that TV persistence on microgreen leaves was plant variety dependent. In addition, this study provided a preliminary estimation on the risk of HuNoV contamination in a microgreen production system which will aim the future development of prevention and control measures.
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Affiliation(s)
- Wenjun Deng
- Department of Food Science, Center for Food Safety, University of Arkansas System Division of Agriculture, 1371 West Altheimer Dr., Fayetteville, AR, 72704, USA
| | - Kristen E Gibson
- Department of Food Science, Center for Food Safety, University of Arkansas System Division of Agriculture, 1371 West Altheimer Dr., Fayetteville, AR, 72704, USA.
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3
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Eshaghi Gorji M, Li D. Photoinactivation of bacteriophage MS2, Tulane virus and Vibrio parahaemolyticus in oysters by microencapsulated rose bengal. FOOD QUALITY AND SAFETY 2022. [DOI: 10.1093/fqsafe/fyac017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Objectives
Bivalve molluscan shellfish such as oysters are important vectors for the transmission of foodborne pathogens including both viruses and bacteria. Photoinactivation provides a cold-sterilization option against the contamination as excited photosensitizers could transfer electronic energy to oxygen molecules producing reactive oxygen species such as singlet oxygen, leading to oxidative damage and death of the pathogens. However, the efficacy of photoinactivation is very often compromised by the presence of food matrix due to the non-selective reactions of short-lived singlet oxygen with the organic matters other than the target pathogens.
Materials and Methods
In order to address this issue, we encapsulated a food grade photosensitizer rose bengal (RB) in alginate microbeads. An extra coating of chitosan effectively prevented the release of RB from the microbeads in seawater, and more importantly, enhanced the selectivity of the photoinactivation via the electrostatic interactions between cationic chitosan and anionic charge of the virus particles (bacteriophage MS2 and Tulane virus) and the gram-negative bacteria Vibrio parahaemolyticus.
Results
The treatment of oysters with microencapsulated RB resulted in significantly higher reductions of MS2 phage, Tulane virus and V. parahaemolyticus than free RB and non-RB carrying microbeads (P < 0.05) tested with both in vitro and in vivo experimental set-ups. (4)
Conclusions
This study demonstrated a new strategy in delivering comprehensively formulated biochemical sanitizers in bivalve shellfish through their natural filter feeding activity and thereby enhancing the mitigation efficiency of foodborne pathogen contamination.
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Affiliation(s)
- Mohamad Eshaghi Gorji
- Department of Food Science & Technology, Faculty of Science, National University of Singapore, Singapore
| | - Dan Li
- Department of Food Science & Technology, Faculty of Science, National University of Singapore, Singapore
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4
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Zwe YH, Ten MMZ, Pang X, Wong CH, Li D. Differential Survivability of Two Genetically Similar Salmonella Thompson Strains on Pre-harvest Sweet Basil ( Ocimum basilicum) Leaves. Front Microbiol 2021; 12:740983. [PMID: 34950113 PMCID: PMC8689135 DOI: 10.3389/fmicb.2021.740983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 11/12/2021] [Indexed: 11/13/2022] Open
Abstract
Although conventionally considered an animal pathogen, recent evidence increasingly suggests that fresh produce may act as significant transmission vehicles and alternative hosts to Salmonella. This study reports the differential survivability of two genetically similar Salmonella Thompson strains (ST 889B and ST 688C) on the adaxial surface of pre-harvest basil (Ocimum basilicum) leaves. Upon inoculation, two distinct phenomena, a dried water-print or a macroscopic lesion, were observed within 24 h. ST 889B survived better than ST 688C on healthy-looking leaves without lesions, possibly due to its higher biofilm-forming ability. Both strains survived better on the leaves with lesions than on the healthy-looking leaves (ST 688C: 4.39 ± 0.68 vs. 2.18 ± 0.29; ST 889B: 4.78 ± 0.12 vs. 2.83 ± 0.18 log CFU per sample at 6 days post-inoculation). ST 889B caused the formation of lesions at a higher frequency [70/117 leaves (59.8%)] than ST 688C [35/96 leaves (36.5%)]. Thus, we highlighted two distinct Salmonella survival strategies in the basil pathosystem and demonstrated gene expression polymorphism (variations in the expression of the same set of genes) as an indispensable strategy in the colonization of plants as hosts by the human pathogens.
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Affiliation(s)
- Ye Htut Zwe
- Department of Food Science and Technology, National University of Singapore, Singapore, Singapore
| | - Michelle Mei Zhen Ten
- Department of Food Science and Technology, National University of Singapore, Singapore, Singapore
| | - Xinyi Pang
- Department of Food Science and Technology, National University of Singapore, Singapore, Singapore
| | - Chun Hong Wong
- Department of Food Science and Technology, National University of Singapore, Singapore, Singapore
| | - Dan Li
- Department of Food Science and Technology, National University of Singapore, Singapore, Singapore
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5
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Zwe YH, Yadav M, Zhen Ten MM, Srinivasan M, Jobichen C, Sivaraman J, Li D. Bacterial Antagonism of Chromobacterium haemolyticum and Characterization of its Putative Type VI Secretion System. Res Microbiol 2021; 173:103918. [PMID: 34906677 DOI: 10.1016/j.resmic.2021.103918] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 12/08/2021] [Accepted: 12/08/2021] [Indexed: 10/19/2022]
Abstract
This study reports the isolation of a new Chromobacterium haemolyticum strain named WI5 from a hydroponic farming facility. WI5 exhibited remarkable bacterial antagonistic properties, eliminating Salmonella, Escherichia coli, Listeria monocytogenes and Staphylococcus aureus (initial inoculum load ∼105 CFU/ml) in dual-species co-culture biofilms. Antagonism was strictly contact-dependent and highly influenced by nutrient availability. Next, we identified a complete suite of putative Type VI secretion system (T6SS) genes in the WI5 genome, annotated the gene locus architecture, and determined the crystal structure of hallmark T6SS tube protein Hcp1, which revealed a hexameric ring structure with an outer and inner diameter of 77 and 45Å, respectively. Structural comparison with homologs showed differences in the key loops connecting the β-strands in which the conserved residues are located, suggesting a role of these residues in the protein function. The T6SS is well-known to facilitate interbacterial competition, and the putative T6SS characterized herein might be responsible for the remarkable antagonism by C. haemolyticum WI5. Collectively, these findings shed light on the nature of bacterial antagonism and a putative key virulence determinant of C. haemolyticum, which might aid in further understanding its potential ecological role in natural habitats.
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Affiliation(s)
- Ye Htut Zwe
- Department of Food Science & Technology, 2 Science Drive 2, Faculty of Science, National University of Singapore, Singapore 117543
| | - Manisha Yadav
- Department of Biological Sciences, 14 Science Drive 4, Faculty of Science, National University of Singapore, Singapore 117543
| | - Michelle Mei Zhen Ten
- Department of Food Science & Technology, 2 Science Drive 2, Faculty of Science, National University of Singapore, Singapore 117543
| | - Mahalashmi Srinivasan
- Department of Biological Sciences, 14 Science Drive 4, Faculty of Science, National University of Singapore, Singapore 117543
| | - Chacko Jobichen
- Department of Biological Sciences, 14 Science Drive 4, Faculty of Science, National University of Singapore, Singapore 117543
| | - J Sivaraman
- Department of Biological Sciences, 14 Science Drive 4, Faculty of Science, National University of Singapore, Singapore 117543
| | - Dan Li
- Department of Food Science & Technology, 2 Science Drive 2, Faculty of Science, National University of Singapore, Singapore 117543.
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Tan MTH, Xue L, Wang D, Eshaghi Gorji M, Li Y, Gong Z, Li D. The globally re-emerging norovirus GII.2 manifests higher heat resistance than norovirus GII.4 and Tulane virus. J Appl Microbiol 2021; 132:2441-2449. [PMID: 34821445 DOI: 10.1111/jam.15379] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/18/2021] [Accepted: 11/20/2021] [Indexed: 12/11/2022]
Abstract
AIMS To compare the heat stability of two globally prevalent human norovirus (HuNoV) strains (GII.2[P16] and GII.4[P16]) and a commonly used HuNoV surrogate, Tulane virus (TV). METHODS AND RESULTS With the use of a newly developed zebrafish larvae platform, we measured the change of infectivity of HuNoV GII.2[P16] and GII.4[P16] toward mild heat treatment at 55°C for 5 min. TV was tested with the same experimental design. As a result, the virus infectivity measurement clearly indicated the higher heat resistance of HuNoV GII.2[P16] (no reduction) than GII.4[P16] (>0.8-log TCID50 ml-1 reduction) and TV (2.5-log TCID50 ml-1 reduction). Further exploration revealed higher virus structural stability of HuNoV GII.2 than GII.4 strains by the use of different clinical samples with different evaluation methods. CONCLUSION The inactivation data generated from the surrogate virus TV cannot be used directly to describe the inactivation of HuNoV. The phylogenetic classification of HuNoVs may correlate with the virus stability and/or circulation dynamics. SIGNIFICANCE AND IMPACT OF THE STUDY This study is expected to serve as an important reference when revisiting the numerous previous data evaluating HuNoV inactivation conditions in foods with the use of TV as the cultivable surrogate or with genuine HuNoV but using molecular methods. The higher resistance of NoV GII.2 strains than GII.4 strains toward inactivation treatment supplies a possible explanation for the global re-emerging of NoV GII.2 epidemic in recent years.
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Affiliation(s)
- Malcolm Turk Hsern Tan
- Department of Food Science & Technology, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - Liang Xue
- Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Dapeng Wang
- Department of Food Science and Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Mohamad Eshaghi Gorji
- Department of Food Science & Technology, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - Yan Li
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - Zhiyuan Gong
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - Dan Li
- Department of Food Science & Technology, Faculty of Science, National University of Singapore, Singapore, Singapore
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7
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Zhao X, da Silva MBR, Van der Linden I, Franco BDGM, Uyttendaele M. Behavior of the Biological Control Agent Bacillus thuringiensis subsp. aizawai ABTS-1857 and Salmonella enterica on Spinach Plants and Cut Leaves. Front Microbiol 2021; 12:626029. [PMID: 33613492 PMCID: PMC7886684 DOI: 10.3389/fmicb.2021.626029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 01/15/2021] [Indexed: 11/13/2022] Open
Abstract
Fresh produce has been identified as an important vehicle for the transmission of foodborne pathogens. This study evaluated the behavior of vegetative cells and spores of Bacillus thuringiensis, one of the main biological control agents (BCAs) used in the world, and Salmonella enterica on spinach plants (pre-harvest) and spinach cut leaves (post-harvest) at 12°C, experimentally inoculated as single or co-cultures. The results evidenced that spray-inoculated commercial BCA containing Bacillus thuringiensis subsp. aizawai ABTS-1857 (BTa ABTS-1857) spores persisted well on spinach leaves in both pre- and post-harvest simulations. However, when BTa ABTS-1857 vegetative cells were spray-inoculated, more than 2 log reductions in the counts of B. thuringiensis were observed during 20 days pre- and 5 days post-harvest simulations, respectively. The counts of S. Montevideo on the spinach cut leaves during post-harvest storage at 12°C for 5 days remained unchanged, whereas 1 log reduction was noted during pre-harvest. Moreover, during pre-harvest simulation, when co-inoculated with BTa ABTS-1857 vegetative cells or spores, additional 0.5 or 1.0 log reductions were detected on the counts of S. Montevideo in the spinach leaves on the 10th day. These results were obtained under laboratory conditions, and further findings in longitudinal studies from farm (in the agricultural field) to retail (end of shelf life) will contribute to understanding of the role of B. thuringiensis as a BCA on growth/survival of Salmonella spp. in fresh produce.
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Affiliation(s)
- Xingchen Zhao
- Food Microbiology and Food Preservation Research Unit, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Marcelo Belchior Rosendo da Silva
- FoRC - Food Research Center, Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Inge Van der Linden
- Food Microbiology and Food Preservation Research Unit, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Bernadette D G M Franco
- FoRC - Food Research Center, Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Mieke Uyttendaele
- Food Microbiology and Food Preservation Research Unit, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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8
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Pandey V, Swami RK, Narula A. Harnessing the Potential of Roots of Traditional Power Plant: Ocimum. FRONTIERS IN PLANT SCIENCE 2021; 12:765024. [PMID: 34790216 PMCID: PMC8591311 DOI: 10.3389/fpls.2021.765024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 09/30/2021] [Indexed: 05/13/2023]
Abstract
Genus Ocimum of Labiatae is well known in all traditional medicinal systems like Ayurveda, Unani, Siddha, and Homeopathy. The pharmaceutical activities of different species of Ocimum attributed to all plant parts. Roots are the most significant vital organ of the plant, as they absorb water and nutrients from soil and transport to aerial parts of the plants. Roots of Ocimum were found helpful with free-radical scavenging activity to improve physical and mental strength as well as to treat diabetes, malaria, and liver problems. Antibacterial activity of Ocimum roots and its main component, rosmarinic acid, is very beneficial to protect against several human pathogens, including bacteria and viruses. Being so important in every way, roots of Ocimum need healthy rhizosphere. Bacteria, fungi, nematodes, types of soil, fungicide, pesticides, salt, radioactive elements, as well as heavy metal contaminations, affect roots and overall growth of Ocimum in positive or negative ways. Each component of rhizosphere (natural, treatment or contamination) affects the roots, which highlights current ecological scenario to discover biosafe and more productive approaches. For such prestigious organ of Ocimum, development of in vitro root cultures and hairy root cultures assists to reduce the efforts and timing of the traditional cultivation process along with elimination of negative factors in rhizosphere. Different strains of Agrobacterium rhizogenes, various media compositions, as well as discrete treatments, like elicitors, on nonidentical species or cultivars of Ocimum boost the root induction, biomass, and accumulation of phytoceuticals differently. Hairy roots and in vitro roots of Ocimum accumulate higher quantity of therapeutic metabolites. These metabolites include several phenolics (like rosmarinic acid, 3-hydroxybenzoic acid, m-coumaric acid, p-coumaric acid, caffeic acid, ferulic acid, vanillic acid, chicoric acid, and lithospermic acid), triterpenes (such as betulinic acid, 3-epimaslinic acid, alphitolic acid, euscaphic acids, oleanolic acid, and ursolic acid) as well as flavonoids (flavones, flavonols, and dihydroflavonols). This review highlights pharmaceutical applications of Ocimum roots, a great deal of rhizosphere components and in vitro culturing techniques to enhance biomass as well as chief phytoceuticals.
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9
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Evaluation of porcine gastric mucin assay for detection and quantification of human norovirus in fresh herbs and leafy vegetables. Food Microbiol 2019; 84:103254. [DOI: 10.1016/j.fm.2019.103254] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 06/27/2019] [Accepted: 06/28/2019] [Indexed: 12/11/2022]
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10
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Jechalke S, Schierstaedt J, Becker M, Flemer B, Grosch R, Smalla K, Schikora A. Salmonella Establishment in Agricultural Soil and Colonization of Crop Plants Depend on Soil Type and Plant Species. Front Microbiol 2019; 10:967. [PMID: 31156568 PMCID: PMC6529577 DOI: 10.3389/fmicb.2019.00967] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 04/16/2019] [Indexed: 12/20/2022] Open
Abstract
Human pathogenic bacteria, such as Salmonella enterica, are able to colonize crop plants. So far, not much is known about biotic and abiotic factors influencing this colonization in field soil. This understanding, however, is imperative for the provision of safe fresh produce to the consumer. In this study, we investigated the effects of soil type, organic fertilization, plant species and the way of Salmonella entry into the plant production system, on the survival of S. enterica in soil as well as the colonization of plants. The selected S. enterica serovar Typhimurium strain 14028s, S. Typhimurium strain LT2 and S. Senftenberg were able to persist in soil for several weeks. Salmonella's persistence in soil was prolonged in loamy, if compared to sandy soil, and when applied together with organic fertilizer. The leaves of lettuce and corn salad were colonized by S. enterica providing evidence for internalization from the soil via the root. Colonization rates were affected by soil type, plant species and S. enterica strain. Overall, S. enterica was detected in leaves of 0.5-0.9% of the plants, while lettuce was more frequently colonized than corn salad. Plants grown in sandy soil were more often colonized than plants grown in loamy soil. After spray inoculation, S. enterica could be detected on and in leaves for several weeks by cultivation-depending methods, confirmed by confocal microscopy using GFP-labeled S. Typhimurium 14028s. On the one hand, transcriptome data from S. Typhimurium 14028s assessed in response to lettuce medium or lettuce root exudates showed an upregulation of genes associated with biofilm formation and virulence. On the other hand, lettuce inoculated with S. Typhimurium 14028s showed a strong upregulation of genes associated with plant immune response and genes related to stress response. In summary, these results showed that organic fertilizers can increase the persistence of Salmonella in soil and that soil type and plant species play a crucial role in the interactions between human pathogens and crop plants. This understanding is therefore a starting point for new strategies to provide safe food for the consumer.
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Affiliation(s)
- Sven Jechalke
- Institute for Phytopathology, Justus Liebig University Giessen, Gießen, Germany
| | - Jasper Schierstaedt
- Leibniz Institute of Vegetable and Ornamental Crops, Plant-Microbe Systems, Großbeeren, Germany
| | - Marlies Becker
- Federal Research Centre for Cultivated Plants, Julius Kühn-Institut (JKI), Institute for Epidemiology and Pathogen Diagnostics, Braunschweig, Germany
| | - Burkhardt Flemer
- Leibniz Institute of Vegetable and Ornamental Crops, Plant-Microbe Systems, Großbeeren, Germany
| | - Rita Grosch
- Leibniz Institute of Vegetable and Ornamental Crops, Plant-Microbe Systems, Großbeeren, Germany
| | - Kornelia Smalla
- Federal Research Centre for Cultivated Plants, Julius Kühn-Institut (JKI), Institute for Epidemiology and Pathogen Diagnostics, Braunschweig, Germany
| | - Adam Schikora
- Federal Research Centre for Cultivated Plants, Julius Kühn-Institut (JKI), Institute for Epidemiology and Pathogen Diagnostics, Braunschweig, Germany
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11
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Risk of Human Pathogen Internalization in Leafy Vegetables During Lab-Scale Hydroponic Cultivation. HORTICULTURAE 2019. [DOI: 10.3390/horticulturae5010025] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Controlled environment agriculture (CEA) is a growing industry for the production of leafy vegetables and fresh produce in general. Moreover, CEA is a potentially desirable alternative production system, as well as a risk management solution for the food safety challenges within the fresh produce industry. Here, we will focus on hydroponic leafy vegetable production (including lettuce, spinach, microgreens, and herbs), which can be categorized into six types: (1) nutrient film technique (NFT), (2) deep water raft culture (DWC), (3) flood and drain, (4) continuous drip systems, (5) the wick method, and (6) aeroponics. The first five are the most commonly used in the production of leafy vegetables. Each of these systems may confer different risks and advantages in the production of leafy vegetables. This review aims to (i) address the differences in current hydroponic system designs with respect to human pathogen internalization risk, and (ii) identify the preventive control points for reducing risks related to pathogen contamination in leafy greens and related fresh produce products.
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12
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Rocard JM, Asadishad B, Samonte PRV, Ghoshal S, Tufenkji N. Natural freeze-thaw cycles may increase the risk associated with Salmonella contamination in surface and groundwater environments. WATER RESEARCH X 2018; 1:100005. [PMID: 31194033 PMCID: PMC6549903 DOI: 10.1016/j.wroa.2018.10.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Groundwater contamination by bacteria poses a serious threat to our drinking water supplies. In cold climate regions, microorganisms introduced to upper soil layers by spreading of animal manure are subject to low temperatures and multiple cycles of freezing and thawing at the beginning of winter and during spring melt. We investigated the influence of temperature fluctuations around the freezing point, known as freeze-thaw (FT), on the inactivation rates, growth, and biofilm formation of a manure-isolated strain of Salmonella typhimurium. Moreover, the effects of FT on the transport characteristics of S. typhimurium in quartz sand were monitored in model porewater solutions of two different ionic strengths (IS: 10 and 100 mM KCl) and two different humic acid (HA) concentrations (1 and 5 mg/L). Increasing numbers of FT cycles were found to decrease the deposition of S. typhimurium onto quartz sand and increase the percentage of detached cells in sand-packed column experiments. Based on the calculated bacterial attachment efficiencies, the predicted minimum setback distances between the location of water supply wells and manure spreading activities are higher when the effects of FT are taken into consideration. While FT treatment significantly affected cell viability (in the presence of HA), most cells were in a viable but non-culturable (VBNC) state with compromised ability to form biofilm. This investigation demonstrates the effects of spring temperature variations in upper soil layers on S. typhimurium properties and the potential increased risk of bacterial contamination in representative aquifer environments in cold climate regions.
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Affiliation(s)
- Jennifer M. Rocard
- Department of Chemical Engineering, McGill University, Montreal, Quebec, H3A 0C5, Canada
- Department of Civil Engineering, McGill University, Montreal, Quebec, H3A 0C3, Canada
| | - Bahareh Asadishad
- Department of Chemical Engineering, McGill University, Montreal, Quebec, H3A 0C5, Canada
| | - Pamela Rose V. Samonte
- Department of Chemical Engineering, McGill University, Montreal, Quebec, H3A 0C5, Canada
| | - Subhasis Ghoshal
- Department of Civil Engineering, McGill University, Montreal, Quebec, H3A 0C3, Canada
| | - Nathalie Tufenkji
- Department of Chemical Engineering, McGill University, Montreal, Quebec, H3A 0C5, Canada
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