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Waszczuk W, Czajkowska J, Dutkiewicz A, Klasa B, Carolak E, Aleksandrowicz A, Grzymajlo K. It takes two to attach - endo-1,3-β-d-glucanase as a potential receptor of mannose-independent, FimH-dependent Salmonella Typhimurium binding to spinach leaves. Food Microbiol 2024; 121:104519. [PMID: 38637081 DOI: 10.1016/j.fm.2024.104519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 03/07/2024] [Accepted: 03/09/2024] [Indexed: 04/20/2024]
Abstract
Currently, fresh, unprocessed food has become a relevant element of the chain of transmission of enteropathogenic infections. To survive on a plant surface and further spread the infections, pathogens like Salmonella have to attach stably to the leaf surface. Adhesion, driven by various virulence factors, including the most abundant fim operon encoding type 1 fimbriae, is usually an initial step of infection, preventing physical removal of the pathogen. Adhesion properties of Salmonella's type 1 fimbriae and its FimH adhesin were investigated intensively in the past. However, there is a lack of knowledge regarding its role in interaction with plant cells. Understanding the mechanisms and structures involved in such interaction may facilitate efforts to decrease the risk of contamination and increase fresh food safety. Here, we applied Salmonella genome site-directed mutagenesis, adhesion assays, protein-protein interactions, and biophysics methods based on surface plasmon resonance to unravel the role of FimH adhesin in interaction with spinach leaves. We show that FimH is at least partially responsible for Salmonella binding to spinach leaves, and this interaction occurs in a mannose-independent manner. Importantly, we identified a potential FimH receptor as endo-1,3-β-d-Glucanase and found that this interaction is strong and specific, with a dissociation constant in the nanomolar range. This research advances our comprehension of Salmonella's interactions with plant surfaces, offering insights that can aid in minimizing contamination risks and improving the safety of fresh, unprocessed foods.
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Affiliation(s)
- Wiktoria Waszczuk
- Wrocław University of Environmental and Life Sciences, Faculty of Veterinary Medicine, Department of Biochemistry and Molecular Biology, Poland.
| | - Joanna Czajkowska
- Wrocław University of Environmental and Life Sciences, Faculty of Veterinary Medicine, Department of Biochemistry and Molecular Biology, Poland.
| | - Agata Dutkiewicz
- Wrocław University of Environmental and Life Sciences, Faculty of Veterinary Medicine, Department of Biochemistry and Molecular Biology, Poland.
| | - Beata Klasa
- Wrocław University of Environmental and Life Sciences, Faculty of Veterinary Medicine, Department of Biochemistry and Molecular Biology, Poland.
| | - Ewa Carolak
- Wrocław University of Environmental and Life Sciences, Faculty of Veterinary Medicine, Department of Biochemistry and Molecular Biology, Poland.
| | - Adrianna Aleksandrowicz
- Wrocław University of Environmental and Life Sciences, Faculty of Veterinary Medicine, Department of Biochemistry and Molecular Biology, Poland.
| | - Krzysztof Grzymajlo
- Wrocław University of Environmental and Life Sciences, Faculty of Veterinary Medicine, Department of Biochemistry and Molecular Biology, Poland.
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2
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Kaczmarek-Szczepańska B, Zasada L, Wekwejt M, Brzezinska MS, Michno A, Ronowska A, Ciesielska M, Kovtun G, Cuberes MT. PVA-Based Films with Strontium Titanate Nanoparticles Dedicated to Wound Dressing Application. Polymers (Basel) 2024; 16:484. [PMID: 38399862 PMCID: PMC10893095 DOI: 10.3390/polym16040484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 01/30/2024] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
Bioactive materials may be applied in tissue regeneration, and an example of such materials are wound dressings, which are used to accelerate skin healing, especially after trauma. Here, we proposed a novel dressing enriched by a bioactive component. The aim of our study was to prepare and characterize poly(vinyl alcohol) films modified with strontium titanate nanoparticles. The physicochemical properties of films were studied, such as surface free energy and surface roughness, as well as the mechanical properties of materials. Moreover, different biological studies were carried out, like in vitro hemo- and cyto-compatibility, biocidal activity, and anti-biofilm formation. Also, the degradation of the materials' utilization possibilities and enzymatic activity in compost were checked. The decrease of surface free energy, increase of roughness, and improvement of mechanical strength were found after the addition of nanoparticles. All developed films were cyto-compatible, and did not induce a hemolytic effect on the human erythrocytes. The PVA films containing the highest concentration of STO (20%) reduced the proliferation of Eschericha coli, Pseudomonas aeruginosa, and Staphylococcus aureus significantly. Also, all films were characterized by surface anti-biofilm activity, as they significantly lowered the bacterial biofilm abundance and its dehydrogenase activity. The films were degraded by the compost microorganism. However, PVA with the addition of 20%STO was more difficult to degrade. Based on our results, for wound dressing application, we suggest using bioactive films based on PVA + 20%STO, as they were characterized by high antibacterial properties, favorable physicochemical characteristics, and good biocompatibility with human cells.
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Affiliation(s)
- Beata Kaczmarek-Szczepańska
- Department of Biomaterials and Cosmetics Chemistry, Faculty of Chemistry, Nicolaus Copernicus University, Gagarin 7, 87-100 Toruń, Poland; (L.Z.); (M.C.)
| | - Lidia Zasada
- Department of Biomaterials and Cosmetics Chemistry, Faculty of Chemistry, Nicolaus Copernicus University, Gagarin 7, 87-100 Toruń, Poland; (L.Z.); (M.C.)
| | - Marcin Wekwejt
- Department of Biomaterials Technology, Faculty of Mechanical Engineering and Ship Technology, Gdańsk University of Technology, 80-233 Gdańsk, Poland;
| | - Maria Swiontek Brzezinska
- Department of Environmental Microbiology and Biotechnology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Torun, Lwowska 1, 87-100 Torun, Poland;
| | - Anna Michno
- Department of Molecular Medicine, Medical University of Gdańsk, 80-210 Gdańsk, Poland; (A.M.); (A.R.)
| | - Anna Ronowska
- Department of Molecular Medicine, Medical University of Gdańsk, 80-210 Gdańsk, Poland; (A.M.); (A.R.)
| | - Magdalena Ciesielska
- Department of Biomaterials and Cosmetics Chemistry, Faculty of Chemistry, Nicolaus Copernicus University, Gagarin 7, 87-100 Toruń, Poland; (L.Z.); (M.C.)
| | - Ganna Kovtun
- Institute of Magnetism NAS of Ukraine and MES of Ukraine, Blvd. Acad. Vernadsky 36-b, 03142 Kyiv, Ukraine;
- Department of Applied Mechanics and Project Engineering, Mining and Industrial Engineering School of Almaden, University of Castilla-La Mancha, Plaza Manuel Meca 1, 13400 Almadén, Spain;
| | - M. Teresa Cuberes
- Department of Applied Mechanics and Project Engineering, Mining and Industrial Engineering School of Almaden, University of Castilla-La Mancha, Plaza Manuel Meca 1, 13400 Almadén, Spain;
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3
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Richert A, Kalwasińska A, Felföldi T, Szabó A, Fehér D, Dembińska K, Brzezinska MS. Characterization of bacterial biofilms developed on the biodegradable polylactide and polycaprolactone polymers containing birch tar in an aquatic environment. MARINE POLLUTION BULLETIN 2024; 199:115922. [PMID: 38157832 DOI: 10.1016/j.marpolbul.2023.115922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 12/06/2023] [Accepted: 12/10/2023] [Indexed: 01/03/2024]
Abstract
Birch tar was added to polylactide (PLA) and polycaprolactone (PCL) to create films with antimicrobial properties. After incubating the films for seven days in lake water, the diversity of bacterial communities developed on the surfaces of PCL and PLA with embedded birch tar (1 %, 5 %, and 10 %, w/w) was assessed with amplicon sequencing of the 16S rRNA gene on a MiSeq platform (Illumina). Notably, Aquabacterium and Caulobacter were more abundant at the surface of PCL compared to PLA (13.4 % vs 0.2 %, p < 0.001 and 9.5 % vs 0.2 %, p < 0.001, respectively) while Hydrogenophaga was significantly more abundant at the surface of PLA compared to PCL (6.1 % vs 1.8 %, p < 0.01). Overall, lower birch tar concentrations (1 % and 5 % on both polymers) stimulated bacterial diversity in biofilms compared to the control. The number of reeds assigned to Flavobacterium and Aquabacterium showed a rising trend with the increase of birch tar concentration on the surface of both polymers.
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Affiliation(s)
- Agnieszka Richert
- Department of Genetics, Faculty of Biology and Veterinary Science, Nicolaus Copernicus University in Toruń, Gagarina 11, 87-100 Torun, Poland.
| | - Agnieszka Kalwasińska
- Department of Environmental Microbiology and Biotechnology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Gagarina 11, 87-100 Torun, Poland
| | - Tamás Felföldi
- Institute of Aquatic Ecology, Centre for Ecological Research, Karolina 29, 1113 Budapest, Hungary
| | - Attila Szabó
- Institute of Aquatic Ecology, Centre for Ecological Research, Karolina 29, 1113 Budapest, Hungary; Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Lennart Hjelms väg 9, SE-75007 Uppsala, Sweden
| | - Dóra Fehér
- Department of Microbiology, ELTE Eötvös Loránd University, Pázmány Péter stny. 1/c, H-1117 Budapest, Hungary
| | - Katarzyna Dembińska
- Department of Environmental Microbiology and Biotechnology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Gagarina 11, 87-100 Torun, Poland
| | - Maria Swiontek Brzezinska
- Department of Environmental Microbiology and Biotechnology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Gagarina 11, 87-100 Torun, Poland
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4
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Thomas GA, Paradell Gil T, Müller CT, Rogers HJ, Berger CN. From field to plate: How do bacterial enteric pathogens interact with ready-to-eat fruit and vegetables, causing disease outbreaks? Food Microbiol 2024; 117:104389. [PMID: 37919001 DOI: 10.1016/j.fm.2023.104389] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 09/11/2023] [Accepted: 09/17/2023] [Indexed: 11/04/2023]
Abstract
Ready-to-eat fruit and vegetables are a convenient source of nutrients and fibre for consumers, and are generally safe to eat, but are vulnerable to contamination with human enteric bacterial pathogens. Over the last decade, Salmonella spp., pathogenic Escherichia coli, and Listeria monocytogenes have been linked to most of the bacterial outbreaks of foodborne illness associated with fresh produce. The origins of these outbreaks have been traced to multiple sources of contamination from pre-harvest (soil, seeds, irrigation water, domestic and wild animal faecal matter) or post-harvest operations (storage, preparation and packaging). These pathogens have developed multiple processes for successful attachment, survival and colonization conferring them the ability to adapt to multiple environments. However, these processes differ across bacterial strains from the same species, and across different plant species or cultivars. In a competitive environment, additional risk factors are the plant microbiome phyllosphere and the plant responses; both factors directly modulate the survival of the pathogens on the leaf's surface. Understanding the mechanisms involved in bacterial attachment to, colonization of, and proliferation, on fresh produce and the role of the plant in resisting bacterial contamination is therefore crucial to reducing future outbreaks.
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Affiliation(s)
- Gareth A Thomas
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Teresa Paradell Gil
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Carsten T Müller
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Hilary J Rogers
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Cedric N Berger
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK.
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5
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Han M, Zarkani AA, Duan Y, Grimm M, Trotereau J, Virlogeux-Payant I, Schikora A. Bidirectional Comparisons Revealed Functional Patterns in Interaction between Salmonella enterica and Plants. PLANTS (BASEL, SWITZERLAND) 2024; 13:414. [PMID: 38337947 PMCID: PMC10857149 DOI: 10.3390/plants13030414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/22/2024] [Accepted: 01/29/2024] [Indexed: 02/12/2024]
Abstract
Plants may harbor the human pathogen Salmonella enterica. Interactions between S. enterica and different plant species have been studied in individual reports. However, disparities arising from the distinct experimental conditions may render a meaningful comparison very difficult. This study explored interaction patterns between different S. enterica strains including serovars Typhimurium 14028s and LT2 and serovar Senftenberg, and different plants (Arabidopsis, lettuce, and tomato) in one approach. Better persistence of S. enterica serovar Typhimurium strains was observed in all tested plants, whereas the resulting symptoms varied depending on plant species. Genes encoding pathogenesis-related proteins were upregulated in plants inoculated with Salmonella. Furthermore, transcriptome of tomato indicated dynamic responses to Salmonella, with strong and specific responses already 24 h after inoculation. By comparing with publicly accessible Arabidopsis and lettuce transcriptome results generated in a similar manner, constants and variables were displayed. Plants responded to Salmonella with metabolic and physiological adjustments, albeit with variability in reprogrammed orthologues. At the same time, Salmonella adapted to plant leaf-mimicking media with changes in biosynthesis of cellular components and adjusted metabolism. This study provides insights into the Salmonella-plant interaction, allowing for a direct comparison of responses and adaptations in both organisms.
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Affiliation(s)
- Min Han
- Julius Kühn Institute (JKI)—Federal Research Centre for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, Messeweg 11/12, 38104 Braunschweig, Germany; (M.H.)
- INRAE Val de Loire, Université de Tours, L’Unité Mixte de Recherche Infectiologie et Santé Publique (UMR ISP), 37380 Nouzilly, France
| | - Azhar A. Zarkani
- Julius Kühn Institute (JKI)—Federal Research Centre for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, Messeweg 11/12, 38104 Braunschweig, Germany; (M.H.)
| | - Yongming Duan
- Julius Kühn Institute (JKI)—Federal Research Centre for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, Messeweg 11/12, 38104 Braunschweig, Germany; (M.H.)
| | - Maja Grimm
- Julius Kühn Institute (JKI)—Federal Research Centre for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, Messeweg 11/12, 38104 Braunschweig, Germany; (M.H.)
| | - Jérôme Trotereau
- INRAE Val de Loire, Université de Tours, L’Unité Mixte de Recherche Infectiologie et Santé Publique (UMR ISP), 37380 Nouzilly, France
| | - Isabelle Virlogeux-Payant
- INRAE Val de Loire, Université de Tours, L’Unité Mixte de Recherche Infectiologie et Santé Publique (UMR ISP), 37380 Nouzilly, France
| | - Adam Schikora
- Julius Kühn Institute (JKI)—Federal Research Centre for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, Messeweg 11/12, 38104 Braunschweig, Germany; (M.H.)
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6
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Gollop R, Kroupitski Y, Matz I, Chahar M, Shemesh M, Sela Saldinger S. Bacillus strain BX77: a potential biocontrol agent for use against foodborne pathogens in alfalfa sprouts. FRONTIERS IN PLANT SCIENCE 2024; 15:1287184. [PMID: 38313804 PMCID: PMC10834763 DOI: 10.3389/fpls.2024.1287184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 01/02/2024] [Indexed: 02/06/2024]
Abstract
Despite regulatory and technological measures, edible sprouts are still often involved in foodborne illness and are considered a high-risk food. The present study explored the potential of spore-forming Bacillus isolates to mitigate Salmonella and Escherichia coli contamination of alfalfa sprouts. Food-derived Bacillus strains were screened for antagonistic activity against S. enterica serovar Typhimurium SL1344 (STm) and enteropathogenic E. coli O55:H7. Over 4 days of sprouting, levels of STm and E. coli on contaminated seeds increased from 2.0 log CFU/g to 8.0 and 3.9 log CFU/g, respectively. Treatment of the contaminated seeds with the most active Bacillus isolate, strain BX77, at 7 log CFU/g seeds resulted in substantial reductions in the levels of STm (5.8 CFU/g) and E. coli (3.9 log CFU/g) in the sprouted seeds, compared to the control. Similarly, co-culturing STm and BX77 in sterilized sprout extract at the same ratio resulted in growth inhibition and killed the Salmonella. Confocal-microscopy experiments using seeds supplemented with mCherry-tagged Salmonella revealed massive colonization of the seed coat and the root tip of 4-day-old sprouted seeds. In contrast, very few Salmonella cells were observed in sprouted seeds grown with BX77. Ca-hypochlorite disinfection of seeds contaminated with a relatively high concentration of Salmonella (5.0 log CFU/g) or treated with BX77 revealed a mild inhibitory effect. However, disinfection followed by the addition of BX77 had a synergistic effect, with a substantial reduction in Salmonella counts (7.8 log CFU/g) as compared to untreated seeds. These results suggest that a combination of chemical and biological treatments warrants further study, toward its potential application as a multi-hurdle strategy to mitigate Salmonella contamination of sprouted alfalfa seeds.
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Affiliation(s)
- Rachel Gollop
- Department of Food Science, Institute for Postharvest and Food Science, The Volcani Institute, Agriculture Research Organization, Rishon LeZion, Israel
| | - Yulia Kroupitski
- Department of Food Science, Institute for Postharvest and Food Science, The Volcani Institute, Agriculture Research Organization, Rishon LeZion, Israel
| | - Ilana Matz
- Department of Food Science, Institute for Postharvest and Food Science, The Volcani Institute, Agriculture Research Organization, Rishon LeZion, Israel
| | - Madhvi Chahar
- Department of Food Science, Institute for Postharvest and Food Science, The Volcani Institute, Agriculture Research Organization, Rishon LeZion, Israel
- Current address: Department of Bio & Nano Technology, Guru Jambheshwar University of Science & Technology, Hisar, India
| | - Moshe Shemesh
- Department of Food Science, Institute for Postharvest and Food Science, The Volcani Institute, Agriculture Research Organization, Rishon LeZion, Israel
| | - Shlomo Sela Saldinger
- Department of Food Science, Institute for Postharvest and Food Science, The Volcani Institute, Agriculture Research Organization, Rishon LeZion, Israel
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7
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Liu X, Li Y, Micallef SA. Natural variation and drought-induced differences in metabolite profiles of red oak-leaf and Romaine lettuce play a role in modulating the interaction with Salmonella enterica. Int J Food Microbiol 2023; 385:109998. [PMID: 36371998 DOI: 10.1016/j.ijfoodmicro.2022.109998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 10/14/2022] [Accepted: 10/25/2022] [Indexed: 11/12/2022]
Abstract
Nutrients on produce surfaces are vital for successful enteric pathogen colonisation. In this study, we investigated natural variation in metabolite profiles of Romaine 'Parris Island Cos' and red oak-leaf lettuce 'Mascara' under regular and restricted watering conditions. We also investigated the impact of plant drought stress on the Salmonella - lettuce association. Salmonella Newport and Typhimurium were able to persist at higher levels on regularly watered Romaine than red oak-leaf lettuce. Drought treatment to lettuce impaired epiphytic Salmonella association, with S. Newport and Typhimurium being differentially affected. A higher log reduction of both serotypes was measured on drought-subjected red oak-leaf lettuce plants than controls, but S. Typhimurium was unaffected on water deficit-treated Romaine lettuce (p < 0.05). To assess Salmonella interaction with leaf surface metabolites, leaf washes collected from both cultivars were inoculated and found to be able to support S. Newport growth, with higher levels of Salmonella retrieved from Romaine washes (p < 0.05). The lag phase of S. Newport in washes from water restricted red oak-leaf lettuce was prolonged in relation to regularly-watered controls (p < 0.05). Untargeted plant metabolite profiling using electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) revealed natural variation between Romaine and red oak-leaf lettuce profiles for leaf tissue and leaf washes. Metabolite profile shifts were detected in both lettuce types in response to drought stress, but more unique peaks were detected in red oak-leaf than Romaine lettuce after drought treatment. Variation between the two cultivars was in part attributed to naturally higher levels of flavonoids and anthocyanins in red oak-leaf lettuce compared to Romaine. Moreover, red oak-leaf, but not Romaine lettuce, responded to drought by inducing the accumulation of proline, phenolics, flavonoids and anthocyanins. Drought stress, therefore, enhanced the functional food properties of red oak-leaf lettuce. Salmonella growth dynamics in lettuce leaf washes suggested that natural variation and drought-induced changes in metabolite profiles in lettuce could partly explain the differential susceptibility of various lettuce types to Salmonella, although the primary or secondary metabolites mediating this effect remain unknown. Regulated mild water stress should be investigated as an approach to lower Salmonella contamination risk in suitable lettuce cultivars, while simultaneously boosting the health beneficial quality of lettuce.
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Affiliation(s)
- Xingchen Liu
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD, USA
| | - Yue Li
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, USA
| | - Shirley A Micallef
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD, USA; Center for Food Safety and Security Systems, University of Maryland, College Park, MD, USA.
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8
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Foliar Roughness and Water Content Impact on Escherichia coli Attachment in Baby Leafy Greens. BIOLOGY 2023; 12:biology12010102. [PMID: 36671794 PMCID: PMC9855646 DOI: 10.3390/biology12010102] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/03/2023] [Accepted: 01/04/2023] [Indexed: 01/12/2023]
Abstract
Understanding the relation between the susceptibility of different leafy greens to human pathogen contamination and leaf traits can contribute to increase the food safety of the fresh vegetable industry. The aim of this research was to evaluate the susceptibility to E. coli ATCC 35218 attachment in 30 accessions of baby leaves, and to identify leaf traits potentially involved in the contamination. The accessions were surface inoculated with a bacterial suspension containing 1 × 107 cells/mL and the attachment was measured 1.5 h after inoculation. Significant differences in attachment were detected between the accessions for p ≤ 0.05. The three most and the three least susceptible accessions were selected and characterized for leaf micro-morphological traits (stomata density and size, surface roughness) and water content. Scanning electron microscopy was used to analyse the stomatal parameters. Roughness was measured by an innovative portable 3D digital microscope. No significant correlation between the attachment of E. coli ATCC 35218 and stomatal parameters was detected, while the attachment was positively correlated with roughness and water content. The E. coli ATCC 35218 population in surface-inoculated leaves was also measured after a UV treatment, which was found to be less effective in reducing bacterial contamination in the rougher leaves. This result suggested that roughness offers UV protection, further highlighting its impact on the microbiological safety of baby leafy greens.
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9
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Elnemr I, Mushtaha M, Sundararaju S, Hasan MR, Tsui KM, Goktepe I. Monitoring the effect of environmental conditions on safety of fresh produce sold in Qatar's wholesale market. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2022; 32:1986-2004. [PMID: 34085573 DOI: 10.1080/09603123.2021.1931050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 05/12/2021] [Indexed: 06/12/2023]
Abstract
Fresh produce imported by Qatar are mostly sold at the wholesale produce market (WPM) located in open-air and near major animal markets and slaughterhouses. This study was the first in Qatar to monitor the effect of environmental conditions on the microbial quality and safety of fresh produce sold at the WPM over 1 year. The monitoring involved the collection of 540 produce samples along with samples of air, soil, and surface swabs. Samples were analyzed for total aerobic bacteria (TAB); generic Listeria spp., Staphylococcus spp., Salmonella spp.; total coliforms and total fungi. Bacterial and fungal isolates were identified using 16S rRNA/ITS rRNA markers. Environmental/sanitary factors significantly impacted the prevalence of microorganisms in all samples tested. Produce quality was rated 'poor' during the months of November-February or May-August, with TAB and coliform counts exceeding 6 and 4 log10 CFU/g, respectively. Bacillus subtilus, Enterobacter cloacae, E. faecium, P. expansium, P. aurantiocandidum, and A. niger were the most abundant species with prevalence rate of 11-30%. The high microbial load of environmental samples indicates that the location of the WPM near livestock markets is likely impacting the microbial quality of fresh produce. Therefore, effective control measures need to be implemented at WPM to improve produce safety yearlong.
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Affiliation(s)
- I Elnemr
- Department of Biological and Environmental Sciences, College of Arts and Sciences, Qatar University, Doha, Qatar
| | - M Mushtaha
- Department of Biological and Environmental Sciences, College of Arts and Sciences, Qatar University, Doha, Qatar
| | | | - Mohammad Rubayet Hasan
- Department of Pathology, Sidra Medicine, Doha, Qatar
- Department of Clinical Pathology and Laboratory Medicine, Weill Cornell Medical College in Qatar, Doha, Qatar
| | - Kin-Ming Tsui
- Department of Pathology, Sidra Medicine, Doha, Qatar
- Department of Clinical Pathology and Laboratory Medicine, Weill Cornell Medical College in Qatar, Doha, Qatar
| | - I Goktepe
- Department of Biological and Environmental Sciences, College of Arts and Sciences, Qatar University, Doha, Qatar
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10
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Grivokostopoulos NC, Makariti IP, Tsadaris S, Skandamis PN. Impact of population density and stress adaptation on the internalization of Salmonella in leafy greens. Food Microbiol 2022; 106:104053. [PMID: 35690446 DOI: 10.1016/j.fm.2022.104053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/26/2022] [Accepted: 04/26/2022] [Indexed: 11/17/2022]
Abstract
Salmonella enterica is capable of entering the interior of leafy greens and establishing in the apoplastic area, a phenomenon known as internalization. The ability of internalized bacteria to evade common disinfection practices poses a well-established risk. Our aim was to study the effect of: i) inoculum size and ii) prior adaptation of Salmonella to sublethal stresses, on the internalization of the pathogen in four leafy vegetables. Spinach, lettuce, arugula and chicory were inoculated, by immersion for 2 min at room temperature with: i) Salmonella Enteritidis at 3.0, 4.0, 5.0, 6.0, 7.0 log CFU/mL and ii) non-adapted or adapted S. Enteritidis to acid (in TSB with 1% glucose, incubated for 24 h at 37 °C), cold (in TSB for 7 days at 4 °C), starvation (0.85% NaCl of pH 6.6, 48 h at 37 °C) or desiccation (1.5 h at 42 °C, 4 days at 21 °C) stress at appx 3.5 log CFU/mL). Inoculated leafy greens were subsequently stored at 5 °C and 20 °C for 2 h and 48 h (n = 2 × 2). Population of internalized Salmonella, after surface decontamination with 1% w/v AgNO3, was assessed on selective media. Even the lowest initial bacterial inoculum was adequate for internalization of Salmonella to occur in leafy vegetables. Non-adapted Salmonella inoculum of 7.0 (maximum) and 3.0 log CFU/mL (lowest inoculation level tested) after short storage (2 h) resulted in 3.7-4.3 and 1.3-1.5 log CFU/g internalized bacterial population, respectively. Colonization (including both attachment and internalization processes), as well as internalization process, were positively correlated to initial inoculum level. These processes reached a different plateau beyond which, no further increase in internalization was observed. Adaptation of the pathogen to mild stresses enhanced internalization (P < 0.05), with desiccation- and acid-adapted Salmonella demonstrating the highest internalization capacity, regardless of the vegetable and storage temperature. These findings could contribute to further elucidation of colonization capacity of Salmonella in leafy vegetables and assist in selecting the proper conditions that contribute to the prevention of fresh produce contamination with Salmonella.
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Affiliation(s)
- N C Grivokostopoulos
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, 118 55, Athens, Greece
| | - I P Makariti
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, 118 55, Athens, Greece
| | - S Tsadaris
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, 118 55, Athens, Greece
| | - P N Skandamis
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, 118 55, Athens, Greece.
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11
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Fratty IS, Shachar D, Katsman M, Yaron S. The activity of BcsZ of Salmonella Typhimurium and its role in Salmonella-plants interactions. Front Cell Infect Microbiol 2022; 12:967796. [PMID: 36081768 PMCID: PMC9445439 DOI: 10.3389/fcimb.2022.967796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 07/25/2022] [Indexed: 11/13/2022] Open
Abstract
Salmonella enterica is one of the most common human pathogens associated with fresh produce outbreaks. The present study suggests that expression of BcsZ, one of the proteins in the bcs complex, enhances the survival of Salmonella Typhimurium on parsley. BcsZ demonstrated glucanase activity with the substrates carboxymethylcellulose and crystalline cellulose, and was responsible for a major part of the S. Typhimurium CMCase activity. Moreover, there was constitutive expression of BcsZ, which was also manifested after exposure to plant polysaccharides and parsley-leaf extract. In an in-planta model, overexpression of BcsZ significantly improved the epiphytic and endophytic survival of S. Typhimurium on/in parsley leaves compared with the wild-type strain and bcsZ null mutant. Interestingly, necrotic lesions appeared on the parsley leaf after infiltration of Salmonella overexpressing BcsZ, while infiltration of the wild-type S. Typhimurium did not cause any visible symptoms. Infiltration of purified BcsZ enzyme, or its degradation products also caused symptoms on parsley leaves. We suggest that the BcsZ degradation products trigger the plant’s defense response, causing local necrotic symptoms. These results indicate that BcsZ plays an important role in the Salmonella-plant interactions, and imply that injured bacteria may take part in these interactions.
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12
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Chahar M, Gollop R, Kroupitski Y, Shemesh M, Sela Saldinger S. Control of Salmonella in mung bean sprouts by antagonistic spore-forming bacilli. Food Control 2022. [DOI: 10.1016/j.foodcont.2022.109276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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13
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Jung J, Schaffner DW. The role of
Salmonella
Newport cell surface structures on bacterial attachment and transfer during cucumber peeling. Lett Appl Microbiol 2022; 75:1246-1253. [DOI: 10.1111/lam.13792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 06/12/2022] [Accepted: 07/16/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Jiin Jung
- Department of Food Science Rutgers University 65 Dudley Road New Brunswick
- School of Occupational and Public Health Toronto Metropolitan University 350 Victoria Street Toronto Ontario Canada M5B 2K3
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14
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Grivokostopoulos NC, Makariti IP, Hilaj N, Apostolidou Z, Skandamis PN. Internalization of Salmonella in Leafy Greens and Impact on Acid Tolerance. Appl Environ Microbiol 2022; 88:e0224921. [PMID: 35108086 PMCID: PMC8939352 DOI: 10.1128/aem.02249-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 01/26/2022] [Indexed: 11/20/2022] Open
Abstract
Salmonella colonizes the surface or the inner part of leafy greens, while the ability of internalized bacteria to evade common disinfection practices may pose a considerable risk. Hereby, we aimed to assess how the colonization and internalization of Salmonella spp. (i) vary with the type of leafy green, the storage conditions (temperature, time), and Salmonella serovar at phenotypic and gene transcriptional level (regarding stress- and virulence- or type III secretion system [T3SS]-associated genes) and (ii) potentially impact the survival of the pathogen against subsequent exposure at lethal pH (2.7), mimicking the gastric acidity. Internalized Salmonella reached 3.0 to 5.0 log CFU/g depending on storage conditions and vegetable, with spinach and chicory allowing the highest (P < 0.05) internalization. Prolonged storage (48 h) at 20°C increased the recovery of internalized Salmonella in spinach and green amaranth by 1.0 to 1.5 log units. Colonization of Salmonella on/in leafy vegetables induced the transcription (maximum fold change [FCmax], ∼2,000) of T3SS-related genes. Interserovar variation regarding the internalization ability of Salmonella was observed only in lettuce and green amaranth in a time- and temperature-dependent manner. Attached cells exhibited higher survival rates against low pH than the internalized subpopulation; however, habituation at 20°C in lettuce and amaranth induced acid tolerance to internalized cells, manifested by the 1.5 to 2.0 log CFU/g survivors after 75 min at pH 2.7. Habituation of Salmonella in vegetable extracts sensitized it toward acid, while indigenous microbiota had limited impact on acid resistance of the organism. These findings reveal physiological aspects of Salmonella colonizing leafy vegetables that could be useful in fresh produce microbial risk assessment. IMPORTANCE Consumption of leafy greens has been increasingly associated with foodborne illnesses, and their contamination could occur at pre- and/or postharvest level. Human pathogens may become passively or actively internalized in plant tissues, thereby escaping decontamination procedures. Plant colonization may impact bacterial physiology such as stress resistance and virulence. In this study, it was demonstrated that internalization of Salmonella spp., at the postharvest level, varied with type of vegetable, serovar, and storage conditions. Attached and internalized subpopulations of Salmonella on/in leafy greens showed distinct physiological responses regarding transcriptional changes of stress- and virulence-associated genes, as well as survival capacity against subsequent exposure to lethal pH (2.7). These findings could contribute to a better understanding and potential (re)definition of the risk of enteric pathogens colonizing leafy greens, as well as to the design of intervention strategies aiming to improve the microbiological safety of fresh produce.
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Affiliation(s)
- N. C. Grivokostopoulos
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
| | - I. P. Makariti
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
| | - N. Hilaj
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
| | - Z. Apostolidou
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
| | - P. N. Skandamis
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
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15
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Enhanced inactivation of Salmonella enterica Enteritidis biofilms on the stainless steel surface by proteinase K in the combination with chlorine. Food Control 2022. [DOI: 10.1016/j.foodcont.2021.108519] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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In vitro efficiency evaluation of phage cocktail for biocontrol of Salmonella spp. in food products. Arch Microbiol 2021; 203:5445-5452. [PMID: 34406443 DOI: 10.1007/s00203-021-02522-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 08/06/2021] [Accepted: 08/09/2021] [Indexed: 10/20/2022]
Abstract
This study used a set of different bacteriophages to control contaminations of Salmonella spp., a major food pathogen. A cocktail of four phages designated based on host range and in vitro lytic assay showed a lower bacteriophage insensitive mutant frequency and considerable stability at 4 °C and 28 °C up to 60 days. The work evaluated the effectiveness of cocktail of four phages in reducing Salmonella spp. in four different food matrices (liquid egg, eggshell, milk, lettuce). A maximum of 1.7 log reduction in Salmonella spp. was achieved upon treatment of liquid eggs with phage cocktail for 72 h at 4 °C. In milk, the application of phage cocktail reduced recoverable Salmonella spp. by 1.9 log and 1.8 log at 28ºC (6 h) and 4ºC (72 h), respectively. A significant 2.9 log reduction of Salmonella spp. was obtained in eggshell after a 6 h incubation and Salmonella spp. was beyond detection level after 24 h at 28ºC. The application of cocktail also reduced Salmonella spp. beyond the detectable level in lettuce after 8 h at 28 °C. Our results indicated considerable stability of phages in different food matrices. Taken together, our findings establish the potential effectiveness of the bacteriophage cocktail as a biocontrol agent for Salmonella spp. in different food matrices.
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17
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López-Gálvez F, Rasines L, Conesa E, Gómez PA, Artés-Hernández F, Aguayo E. Reusable Plastic Crates (RPCs) for Fresh Produce (Case Study on Cauliflowers): Sustainable Packaging but Potential Salmonella Survival and Risk of Cross-Contamination. Foods 2021; 10:foods10061254. [PMID: 34205868 PMCID: PMC8228333 DOI: 10.3390/foods10061254] [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: 05/07/2021] [Revised: 05/26/2021] [Accepted: 05/28/2021] [Indexed: 01/16/2023] Open
Abstract
The handling of fresh fruits and vegetables in reusable plastic crates (RPCs) has the potential to increase the sustainability of packaging in the fresh produce supply chain. However, the utilization of multiple-use containers can have consequences related to the microbial safety of this type of food. The present study assessed the potential cross-contamination of fresh cauliflowers with Salmonella enterica via different contact materials (polypropylene from RPCs, corrugated cardboard, and medium-density fiberboard (MDF) from wooden boxes). Additionally, the survival of the pathogenic microorganism was studied in cauliflowers and the contact materials during storage. The life cycle assessment (LCA) approach was used to evaluate the environmental impact of produce handling containers made from the different food-contact materials tested. The results show a higher risk of cross-contamination via polypropylene compared with cardboard and MDF. Another outcome of the study is the potential of Salmonella for surviving both in cross-contaminated produce and in contact materials under supply chain conditions. Regarding environmental sustainability, RPCs have a lower environmental impact than single-use containers (cardboard and wooden boxes). To exploit the potential environmental benefits of RPCs while ensuring food safety, it is necessary to guarantee the hygiene of this type of container.
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Affiliation(s)
- Francisco López-Gálvez
- Postharvest and Refrigeration Group, Escuela Técnica Superior de Ingeniería Agronómica (ETSIA), Universidad Politécnica de Cartagena (UPCT), Paseo Alfonso XIII, 48, 30203 Cartagena, Spain; (F.L.-G.); (L.R.); (F.A.-H.)
- Food Quality and Health Group, Institute of Plant Biotechnology (UPCT), Campus Muralla del Mar, 30202 Cartagena, Spain;
| | - Laura Rasines
- Postharvest and Refrigeration Group, Escuela Técnica Superior de Ingeniería Agronómica (ETSIA), Universidad Politécnica de Cartagena (UPCT), Paseo Alfonso XIII, 48, 30203 Cartagena, Spain; (F.L.-G.); (L.R.); (F.A.-H.)
- Food Quality and Health Group, Institute of Plant Biotechnology (UPCT), Campus Muralla del Mar, 30202 Cartagena, Spain;
| | - Encarnación Conesa
- Plant Production Department, ETSIA, Institute of Plant Biotechnology (UPCT), Paseo Alfonso XIII, 48, 30203 Cartagena, Spain;
| | - Perla A. Gómez
- Food Quality and Health Group, Institute of Plant Biotechnology (UPCT), Campus Muralla del Mar, 30202 Cartagena, Spain;
| | - Francisco Artés-Hernández
- Postharvest and Refrigeration Group, Escuela Técnica Superior de Ingeniería Agronómica (ETSIA), Universidad Politécnica de Cartagena (UPCT), Paseo Alfonso XIII, 48, 30203 Cartagena, Spain; (F.L.-G.); (L.R.); (F.A.-H.)
- Food Quality and Health Group, Institute of Plant Biotechnology (UPCT), Campus Muralla del Mar, 30202 Cartagena, Spain;
| | - Encarna Aguayo
- Postharvest and Refrigeration Group, Escuela Técnica Superior de Ingeniería Agronómica (ETSIA), Universidad Politécnica de Cartagena (UPCT), Paseo Alfonso XIII, 48, 30203 Cartagena, Spain; (F.L.-G.); (L.R.); (F.A.-H.)
- Food Quality and Health Group, Institute of Plant Biotechnology (UPCT), Campus Muralla del Mar, 30202 Cartagena, Spain;
- Correspondence:
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18
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Reid AN, Conklin C, Beaton K, Donahue N, Jackson E, LoCASCIO B, Marsocci C, Szemreylo E, Szemreylo K. Inoculum Preparation Conditions Influence Adherence of Salmonella enterica Serovars to Red Leaf Lettuce (Lactuca sativa). J Food Prot 2021; 84:857-868. [PMID: 33411904 DOI: 10.4315/jfp-20-301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 12/21/2020] [Indexed: 11/11/2022]
Abstract
ABSTRACT Salmonella enterica has been increasingly linked to outbreaks involving consumption of fresh produce. Although researchers have identified genes whose products are involved in mediating S. enterica-plant interactions, the use of various experimental approaches, serovars, and plant types has generated variable and conflicting data. The purpose of this study was to determine whether conditions under which inocula are prepared for in vitro plant interaction studies influence the outcome of these studies. Seven S. enterica serovars were grown in media that differed in salinity and physical state with incubation at 25 or 37°C. These cultures were then used to inoculate red leaf lettuce, and adherent microbes were subsequently recovered. Although all Salmonella serovars were influenced by inoculum preparation conditions, the amount of variation differed. Analysis of pooled serovar data revealed that inocula prepared from either agar plates or biphasic cultures had higher levels of interaction with red leaf lettuce than those prepared from broth cultures. Incubation at 37°C enhanced adherence after 30 s or 5 days of contact time, and adherence after 1 h of contact time was increased in low-salt medium. Broth inoculum cultures were highly influenced by medium salinity and incubation temperature, whereas plate and biphasic inoculum cultures were only minimally affected. Therefore, inocula prepared from bacteria grown on plates or in biphasic culture would be most suitable for evaluation of strategies used to interfere with plant-Salmonella interactions. However, pooled data mask serovar-specific responses, and care should be taken when extrapolating these findings to individual serovars. The previous association of a serovar with outbreaks involving leafy greens was not correlated with levels of interaction with red leaf lettuce, suggesting that the occurrence of these serovars in or on these commodities does not reflect their fitness in the plant environment. HIGHLIGHTS
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Affiliation(s)
- Anne N Reid
- Department of Biology and Biomedical Sciences, Salve Regina University, 100 Ochre Point Avenue, Newport, Rhode Island 02840, USA
| | - Courtney Conklin
- Department of Biology and Biomedical Sciences, Salve Regina University, 100 Ochre Point Avenue, Newport, Rhode Island 02840, USA
| | - Kimberly Beaton
- Department of Biology and Biomedical Sciences, Salve Regina University, 100 Ochre Point Avenue, Newport, Rhode Island 02840, USA
| | - Nora Donahue
- Department of Biology and Biomedical Sciences, Salve Regina University, 100 Ochre Point Avenue, Newport, Rhode Island 02840, USA
| | - Emily Jackson
- Department of Biology and Biomedical Sciences, Salve Regina University, 100 Ochre Point Avenue, Newport, Rhode Island 02840, USA
| | - Brianna LoCASCIO
- Department of Biology and Biomedical Sciences, Salve Regina University, 100 Ochre Point Avenue, Newport, Rhode Island 02840, USA
| | - Cristina Marsocci
- Department of Biology and Biomedical Sciences, Salve Regina University, 100 Ochre Point Avenue, Newport, Rhode Island 02840, USA
| | - Emily Szemreylo
- Department of Biology and Biomedical Sciences, Salve Regina University, 100 Ochre Point Avenue, Newport, Rhode Island 02840, USA
| | - Katlin Szemreylo
- Department of Biology and Biomedical Sciences, Salve Regina University, 100 Ochre Point Avenue, Newport, Rhode Island 02840, USA
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19
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Sarron E, Gadonna-Widehem P, Aussenac T. Ozone Treatments for Preserving Fresh Vegetables Quality: A Critical Review. Foods 2021; 10:605. [PMID: 33809297 PMCID: PMC8000956 DOI: 10.3390/foods10030605] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 03/04/2021] [Accepted: 03/08/2021] [Indexed: 01/23/2023] Open
Abstract
Ozone is recognized as an antimicrobial agent for vegetables storage, washing, and processing. This strong disinfectant is now being used in the food industry. In this review, the chemical and physical properties of ozone, its generation, and factors affecting ozone processing efficiency were explained as well as recent regulatory developments in the food industry. By then selecting three vegetables, we show that ozone avoids and controls biological growth on vegetables, keeping their attractive appearance and sensorial qualities, assuring nutritional characteristics' retention and maintaining and increasing the shelf-life. In liquid solution, ozone can be used to disinfect processing water and vegetables, and in gaseous form, ozone helps to sanitize and preserve vegetables during storage. The multifunctionality of ozone makes it a promising food processing agent. However, if ozone is improperly used, it causes some deleterious effects on products, such as losses in their sensory quality. For an effective and a safe use of ozone, specific treatment conditions should be determined for all kinds of vegetables. In a last step, we propose highlighting the different essential characteristics of ozone treatment in order to internationally harmonize the data relating to the treatments carried-out.
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Affiliation(s)
| | | | - Thierry Aussenac
- Institut Polytechnique UniLaSalle, Université d’Artois, ULR 7519, 19 Rue Pierre Waguet, BP 30313, 60026 Beauvais, France; (E.S.); (P.G.-W.)
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20
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Oblessuc PR, Melotto M. A Simple Assay to Assess Salmonella enterica Persistence in Lettuce Leaves After Low Inoculation Dose. Front Microbiol 2020; 11:1516. [PMID: 32765443 PMCID: PMC7381196 DOI: 10.3389/fmicb.2020.01516] [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: 01/17/2020] [Accepted: 06/10/2020] [Indexed: 11/17/2022] Open
Abstract
Salmonella enterica is an enterobacterium associated with numerous foodborne illnesses worldwide. Leafy greens have been a common vehicle for disease outbreaks caused by S. enterica. This human pathogen can be introduced into crop fields and potentially contaminate fresh produce. Several studies have shown that S. enterica can survive for long periods in the plant tissues. Often, S. enterica population does not reach high titers in leaves; however, it is still relevant for food safety due to the low infective dose of the pathogen. Thus, laboratory procedures to study the survival of S. enterica in fresh vegetables should be adjusted accordingly. Here, we describe a protocol to assess the population dynamics of S. enterica serovar Typhimurium 14028s in the leaf apoplast of three cultivars of lettuce (Lactuca sativa L.). By comparing a range of inoculum concentrations, we showed that vacuum infiltration of a bacterium inoculum level in the range of 3.4 Log CFU ml–1 (with a recovery of approximately 170 cells per gram of fresh leaves 2 h post inoculation) allows for a robust assessment of bacterial persistence in three lettuce cultivars using serial dilution plating and qPCR methods. We anticipate that this method can be applied to other leaf–human pathogen combinations in an attempt to standardize the procedure for future efforts to screen for plant phenotypic variability, which is useful for breeding programs.
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Affiliation(s)
| | - Maeli Melotto
- Department of Plant Sciences, University of California, Davis, Davis, CA, United States
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21
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Lee KH, Lee JY, Roy PK, Mizan MFR, Hossain MI, Park SH, Ha SD. Viability of Salmonella Typhimurium biofilms on major food-contact surfaces and eggshell treated during 35 days with and without water storage at room temperature. Poult Sci 2020; 99:4558-4565. [PMID: 32868000 PMCID: PMC7598110 DOI: 10.1016/j.psj.2020.05.055] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 04/22/2020] [Accepted: 05/22/2020] [Indexed: 11/30/2022] Open
Abstract
Salmonella is one of the main foodborne pathogens that affect humans and farm animals. The Salmonella genus comprises a group of food-transmitted pathogens that cause highly prevalent foodborne diseases throughout the world. The aim of this study was to appraise the viability of Salmonella Typhimurium biofilm under water treatment at room temperature on different surfaces, specifically stainless steel (SS), plastic (PLA), rubber (RB), and eggshell (ES). After 35 D, the reduction of biofilm on SS, PLA, RB, and ES was 3.35, 3.57, 3.22, and 2.55 log CFU/coupon without water treatment and 4.31, 4.49, 3.50, and 1.49 log CFU/coupon with water treatment, respectively. The dR value (time required to reduce bacterial biofilm by 99% via Weibull modeling) of S. Typhimurium without and with water treatment was the lowest on PLA (176.86 and 112.17 h, respectively) and the highest on ES (485.37 and 2,436.52 h, respectively). The viability of the S. Typhimurium on ES and the 3 food-contact surfaces was monitored for 5 wk (35 D). The results of this study provide valuable information for the control of S. Typhimurium on different surfaces in the food industry, which could reduce the risk to consumers.
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Affiliation(s)
- Ki-Hoon Lee
- Department of Food Science and Technology, Advanced Food Safety Research Group, Chung-Ang University, Anseong, Gyeonggi-do 456-756, South Korea
| | - Ji-Young Lee
- Department of Food Science and Technology, Advanced Food Safety Research Group, Chung-Ang University, Anseong, Gyeonggi-do 456-756, South Korea
| | - Pantu Kumar Roy
- Department of Food Science and Technology, Advanced Food Safety Research Group, Chung-Ang University, Anseong, Gyeonggi-do 456-756, South Korea
| | - Md Furkanur Rahaman Mizan
- Department of Food Science and Technology, Advanced Food Safety Research Group, Chung-Ang University, Anseong, Gyeonggi-do 456-756, South Korea
| | - Md Iqbal Hossain
- Department of Food Science and Technology, Advanced Food Safety Research Group, Chung-Ang University, Anseong, Gyeonggi-do 456-756, South Korea
| | - Si Hong Park
- Department of Food Science and Technology, Oregon State University, Corvallis, OR 97331, USA
| | - Sang-Do Ha
- Department of Food Science and Technology, Advanced Food Safety Research Group, Chung-Ang University, Anseong, Gyeonggi-do 456-756, South Korea.
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22
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Kabir MN, Aras S, Wadood S, Chowdhury S, Fouladkhah AC. Fate and Biofilm Formation of Wild-Type and Pressure-Stressed Pathogens of Public Health Concern in Surface Water and on Abiotic Surfaces. Microorganisms 2020; 8:microorganisms8030408. [PMID: 32183203 PMCID: PMC7143952 DOI: 10.3390/microorganisms8030408] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/10/2020] [Accepted: 03/11/2020] [Indexed: 01/26/2023] Open
Abstract
Since the historic outbreak near Broad Street in London, which serves as cornerstone of modern epidemiology, infectious diseases spread in surface and sub-surface water has been a persisting public health challenge. The current study investigated persistence of wild-type and pressure-stressed Listeria monocytogenes, Escherichia coli O157:H7, and non-typhoidal Salmonella enterica serovars in surface water stored aerobically for up to 28 days at 5, 25, and 37 °C. Additionally, biofilm formation of wild-type and pressure-stressed non-typhoidal Salmonella serovars were monitored on surface of stainless steel and rubber coupons for 28 days at 25 and 37 °C. While L. monocytogenes exhibited a lower (p < 0.05) survival rate at 5 °C, relative to the two Gram-negative pathogens, at higher temperatures of 25 and 37 °C, all three pathogens exhibited similar (p ≥ 0.05) trends for survival in surface water. Both wild-type and pressure-stressed Salmonella serovars in the vast majority of tested times, temperatures, and surfaces exhibited comparable (p ≥ 0.05) persistence and biofilm formation capability. Our study thus indicates the occurrence of contamination could lead to prolonged survival of these microorganisms in low-nutrient environments and highlights the need for preventive measures such as those articulated under Produce Safety Rule of the U.S. Food Safety Modernization Act.
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Affiliation(s)
- Md Niamul Kabir
- Public Health Microbiology Laboratory, Tennessee State University, Nashville, TN 37209, USA; (M.N.K.); (S.A.); (S.W.); (S.C.)
| | - Sadiye Aras
- Public Health Microbiology Laboratory, Tennessee State University, Nashville, TN 37209, USA; (M.N.K.); (S.A.); (S.W.); (S.C.)
| | - Sabrina Wadood
- Public Health Microbiology Laboratory, Tennessee State University, Nashville, TN 37209, USA; (M.N.K.); (S.A.); (S.W.); (S.C.)
| | - Shahid Chowdhury
- Public Health Microbiology Laboratory, Tennessee State University, Nashville, TN 37209, USA; (M.N.K.); (S.A.); (S.W.); (S.C.)
| | - Aliyar Cyrus Fouladkhah
- Public Health Microbiology Laboratory, Tennessee State University, Nashville, TN 37209, USA; (M.N.K.); (S.A.); (S.W.); (S.C.)
- Cooperative Extension Program, Tennessee State University, Nashville, TN 37209, USA
- Correspondence: ; Tel.: +1-970-690-7392
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23
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Oblessuc PR, Matiolli CC, Melotto M. Novel molecular components involved in callose-mediated Arabidopsis defense against Salmonella enterica and Escherichia coli O157:H7. BMC PLANT BIOLOGY 2020; 20:16. [PMID: 31914927 PMCID: PMC6950905 DOI: 10.1186/s12870-019-2232-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 12/30/2019] [Indexed: 05/26/2023]
Abstract
BACKGROUND Food contamination with Salmonella enterica and enterohemorrhagic Escherichia coli is among the leading causes of foodborne illnesses worldwide and crop plants are associated with > 50% of the disease outbreaks. However, the mechanisms underlying the interaction of these human pathogens with plants remain elusive. In this study, we have explored plant resistance mechanisms against these enterobacteria and the plant pathogen Pseudomonas syringae pv. tomato (Pst) DC3118, as an opportunity to improve food safety. RESULTS We found that S. enterica serovar Typhimurium (STm) transcriptionally modulates stress responses in Arabidopsis leaves, including induction of two hallmark processes of plant defense: ROS burst and cell wall modifications. Analyses of plants with a mutation in the potentially STm-induced gene EXO70H4 revealed that its encoded protein is required for stomatal defense against STm and E. coli O157:H7, but not against Pst DC3118. In the apoplast however, EXO70H4 is required for defense against STm and Pst DC3118, but not against E. coli O157:H7. Moreover, EXO70H4 is required for callose deposition, but had no function in ROS burst, triggered by all three bacteria. The salicylic acid (SA) signaling and biosynthesis proteins NPR1 and ICS1, respectively, were involved in stomatal and apoplastic defense, as well as callose deposition, against human and plant pathogens. CONCLUSIONS The results show that EXO70H4 is involved in stomatal and apoplastic defenses in Arabidopsis and suggest that EXO70H4-mediated defense play a distinct role in guard cells and leaf mesophyll cells in a bacteria-dependent manner. Nonetheless, EXO70H4 contributes to callose deposition in response to both human and plant pathogens. NPR1 and ICS1, two proteins involved in the SA signaling pathway, are important to inhibit leaf internalization and apoplastic persistence of enterobacteria and proliferation of phytopathogens. These findings highlight the existence of unique and shared plant genetic components to fight off diverse bacterial pathogens providing specific targets for the prevention of foodborne diseases.
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Affiliation(s)
- Paula Rodrigues Oblessuc
- Department of Plant Sciences, University of California, One Shields Avenue, Davis, CA, 95616, USA
| | | | - Maeli Melotto
- Department of Plant Sciences, University of California, One Shields Avenue, Davis, CA, 95616, USA.
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Rossi C, Chaves-López C, Možina SS, Di Mattia C, Scuota S, Luzzi I, Jenič T, Paparella A, Serio A. Salmonella enterica adhesion: Effect of Cinnamomum zeylanicum essential oil on lettuce. Lebensm Wiss Technol 2019. [DOI: 10.1016/j.lwt.2019.05.026] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Wong CWY, Wang S, Lévesque RC, Goodridge L, Delaquis P. Fate of 43 Salmonella Strains on Lettuce and Tomato Seedlings. J Food Prot 2019; 82:1045-1051. [PMID: 31124714 DOI: 10.4315/0362-028x.jfp-18-435] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 02/15/2019] [Indexed: 11/11/2022]
Abstract
HIGHLIGHTS
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Affiliation(s)
- Catherine W Y Wong
- Department of Food Science, University of British Columbia, 2205 East Mall, Vancouver, British Columbia, Canada V6R 1Z4 (ORCID: https://orcid.org/0000-0002-1239-6677 [C.W.Y.W.]; https://orcid.org/0000-0003-2468-2483 [S.W.])
| | - Siyun Wang
- Department of Food Science, University of British Columbia, 2205 East Mall, Vancouver, British Columbia, Canada V6R 1Z4 (ORCID: https://orcid.org/0000-0002-1239-6677 [C.W.Y.W.]; https://orcid.org/0000-0003-2468-2483 [S.W.])
| | - Roger C Lévesque
- Institute for Integrative and Systems Biology, Université Laval, Québec City, Québec, Canada G1V 0A7
| | - Lawrence Goodridge
- Department of Food Science and Agricultural Chemistry, McGill University, Montréal, Québec, Canada H3A 1E3
| | - Pascal Delaquis
- Agriculture and Agri-Food Canada, 4200 Highway 97, Summerland, British Columbia, Canada V0H 1Z0
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El-Nemr I, Mushtaha M, Irungu P, Asim H, Tang P, Hasan M, Goktepe I. Assessment of Food Safety Knowledge, Self-Reported Practices, and Microbiological Hand Hygiene Levels of Produce Handlers in Qatar. J Food Prot 2019; 82:561-569. [PMID: 30907666 DOI: 10.4315/0362-028x.jfp-18-191] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
HIGHLIGHTS Workers' hygiene is one of the most important risk factors in transferring pathogens to foods. Produce handlers lacked basic knowledge on personal hygiene and food safety. Produce handlers' hand hygiene levels were below set standards. This study is the first of its kind in the region; thus, it helps fill an existing knowledge gap.
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Affiliation(s)
- Israa El-Nemr
- 1 Department of Biological and Environmental Sciences, College of Arts & Sciences, Qatar University, P.O. Box 2713, Doha, Qatar
| | - Mohanad Mushtaha
- 1 Department of Biological and Environmental Sciences, College of Arts & Sciences, Qatar University, P.O. Box 2713, Doha, Qatar
| | - Patrick Irungu
- 2 College of Business & Economics, Qatar University, P.O. Box 2713, Doha, Qatar (ORCID: http://orcid.org/0000-0002-1419-143X [I.G.])
| | - Hammad Asim
- 1 Department of Biological and Environmental Sciences, College of Arts & Sciences, Qatar University, P.O. Box 2713, Doha, Qatar
| | - Patrick Tang
- 3 Department of Pathology, Sidra Medicine, P.O. Box 26999, Doha, Qatar.,4 Weill Cornell Medical College in Qatar, P.O. Box 24144, Doha, Qatar
| | - Mohammad Hasan
- 3 Department of Pathology, Sidra Medicine, P.O. Box 26999, Doha, Qatar.,4 Weill Cornell Medical College in Qatar, P.O. Box 24144, Doha, Qatar
| | - Ipek Goktepe
- 1 Department of Biological and Environmental Sciences, College of Arts & Sciences, Qatar University, P.O. Box 2713, Doha, Qatar
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Čabarkapa I, Čolović R, Đuragić O, Popović S, Kokić B, Milanov D, Pezo L. Anti-biofilm activities of essential oils rich in carvacrol and thymol against Salmonella Enteritidis. BIOFOULING 2019; 35:361-375. [PMID: 31088182 DOI: 10.1080/08927014.2019.1610169] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 03/12/2019] [Accepted: 04/16/2019] [Indexed: 06/09/2023]
Abstract
The aim of the present study was to determine the bioactive compounds in four essential oils (EO's) from Origanum heracleoticum, Origanum vulgare, Thymus vulgaris and Thymus serpyllum and to assess their antimicrobial and anti-biofilm activity against Salmonella Enteritidis. Strains were previously characterized depending on the expression of the extracellular matrix components cellulose and curli fimbriae as rdar (red, dry and rough) and bdar morphotype (brown, dry and rough). This study revealed that the EO's and EOC's (carvacrol and thymol) investigated showed inhibition of biofilm formation at sub-minimum inhibitory concentration. Comparing the efficacy of EO's and EOC's in the inhibition of biofilm formation between the strains with different morphotype (rdar and bdar) did not show a statistically significant difference. Results related to the effectiveness of EO's and EOC's (the essential oil components, carvacrol and thymol) on eradication of preformed 48 h old biofilms indicated that biofilm reduction occurred in a dose-dependent manner over time.
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Affiliation(s)
- Ivana Čabarkapa
- a University of Novi Sad, Institute of Food Technology , Novi Sad , Serbia
| | - Radmilo Čolović
- a University of Novi Sad, Institute of Food Technology , Novi Sad , Serbia
| | - Olivera Đuragić
- a University of Novi Sad, Institute of Food Technology , Novi Sad , Serbia
| | - Sanja Popović
- a University of Novi Sad, Institute of Food Technology , Novi Sad , Serbia
| | - Bojana Kokić
- a University of Novi Sad, Institute of Food Technology , Novi Sad , Serbia
| | - Dubravka Milanov
- b Scientific Veterinary Institute "Novi Sad", Rumenački put bb , Novi Sad , Serbia
| | - Lato Pezo
- c University of Belgrade, Institute of General and Physical Chemistry , Belgrade , Serbia
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Dhakal J, Sharma CS, Nannapaneni R, McDANIEL CD, Kim T, Kiess A. Effect of Chlorine-Induced Sublethal Oxidative Stress on the Biofilm-Forming Ability of Salmonella at Different Temperatures, Nutrient Conditions, and Substrates. J Food Prot 2019; 82:78-92. [PMID: 30586327 DOI: 10.4315/0362-028x.jfp-18-119] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The present study was conducted to evaluate the effect of chlorine-induced oxidative stress on biofilm formation by various Salmonella strains on polystyrene and stainless steel (SS) surfaces at three temperatures (30, 25 [room temperature], and 4°C) in tryptic soy broth (TSB) and 1/10 TSB. Fifteen Salmonella strains (six serotypes) were exposed to a sublethal chlorine concentration (150 ppm of total chlorine) in TSB for 2 h at the predetermined temperatures. The biofilm-forming ability of the Salmonella strains was determined in 96-well polystyrene microtiter plates by using a crystal violet staining method and on SS coupons in 24-well tissue culture plates. All tested strains of Salmonella produced biofilms on both surfaces tested at room temperature and at 30°C. Of the 15 strains tested, none (chlorine stressed and nonstressed) formed biofilm at 4°C. At 30°C, Salmonella Heidelberg (ID 72), Salmonella Newport (ID 107), and Salmonella Typhimurium (ATCC 14028) formed more biofilm than did their respective nonstressed controls on polystyrene ( P ≤ 0.05). At room temperature, only stressed Salmonella Reading (ID 115) in 1/10 TSB had significantly more biofilm formation than did the nonstressed control cells ( P ≤ 0.05). Salmonella strains formed more biofilm in nutrient-deficient medium (1/10 TSB) than in full-strength TSB. At 25°C, chlorine-stressed Salmonella Heidelberg (ATCC 8326) and Salmonella Enteritidis (ATCC 4931) formed stronger biofilms on SS coupons ( P ≤ 0.05) than did the nonstressed cells. These findings suggest that certain strains of Salmonella can produce significantly stronger biofilms on plastic and SS upon exposure to sublethal chlorine.
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Affiliation(s)
- Janak Dhakal
- 1 Department of Grain Science and Industry, Kansas State University, Manhattan, Kansas 66506
| | - Chander S Sharma
- 2 Department of Poultry Science, Mississippi State University, Starkville, Mississippi 39762
| | - Ramakrishna Nannapaneni
- 3 Department of Food, Nutrition, and Health Promotion, Mississippi State University, Starkville, Mississippi 39762
| | - Christopher D McDANIEL
- 2 Department of Poultry Science, Mississippi State University, Starkville, Mississippi 39762
| | - Taejo Kim
- 4 Food and Nutrition Department, University of Wisconsin, Menomonie, Wisconsin 54751, USA
| | - Aaron Kiess
- 2 Department of Poultry Science, Mississippi State University, Starkville, Mississippi 39762
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Mogren L, Windstam S, Boqvist S, Vågsholm I, Söderqvist K, Rosberg AK, Lindén J, Mulaosmanovic E, Karlsson M, Uhlig E, Håkansson Å, Alsanius B. The Hurdle Approach-A Holistic Concept for Controlling Food Safety Risks Associated With Pathogenic Bacterial Contamination of Leafy Green Vegetables. A Review. Front Microbiol 2018; 9:1965. [PMID: 30197634 PMCID: PMC6117429 DOI: 10.3389/fmicb.2018.01965] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Accepted: 08/02/2018] [Indexed: 01/24/2023] Open
Abstract
Consumers appreciate leafy green vegetables such as baby leaves for their convenience and wholesomeness and for adding a variety of tastes and colors to their plate. In Western cuisine, leafy green vegetables are usually eaten fresh and raw, with no step in the long chain from seed to consumption where potentially harmful microorganisms could be completely eliminated, e.g., through heating. A concerning trend in recent years is disease outbreaks caused by various leafy vegetable crops and one of the most important foodborne pathogens in this context is Shiga toxin-producing Escherichia coli (STEC). Other pathogens such as Salmonella, Shigella, Yersinia enterocolitica and Listeria monocytogenes should also be considered in disease risk analysis, as they have been implicated in outbreaks associated with leafy greens. These pathogens may enter the horticultural value network during primary production in field or greenhouse via irrigation, at harvest, during processing and distribution or in the home kitchen/restaurant. The hurdle approach involves combining several mitigating approaches, each of which is insufficient on its own, to control or even eliminate pathogens in food products. Since the food chain system for leafy green vegetables contains no absolute kill step for pathogens, use of hurdles at critical points could enable control of pathogens that pose a human health risk. Hurdles should be combined so as to decrease the risk due to pathogenic microbes and also to improve microbial stability, shelf-life, nutritional properties and sensory quality of leafy vegetables. The hurdle toolbox includes different options, such as physical, physiochemical and microbial hurdles. The goal for leafy green vegetables is multi-target preservation through intelligently applied hurdles. This review describes hurdles that could be used for leafy green vegetables and their biological basis, and identifies prospective hurdles that need attention in future research.
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Affiliation(s)
- Lars Mogren
- Microbial Horticulture, Department of Biosystems and Technology, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Sofia Windstam
- Microbial Horticulture, Department of Biosystems and Technology, Swedish University of Agricultural Sciences, Alnarp, Sweden
- Department of Biological Sciences, SUNY Oswego, Oswego, NY, United States
| | - Sofia Boqvist
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Ivar Vågsholm
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Karin Söderqvist
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Anna K. Rosberg
- Microbial Horticulture, Department of Biosystems and Technology, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Julia Lindén
- Microbial Horticulture, Department of Biosystems and Technology, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Emina Mulaosmanovic
- Microbial Horticulture, Department of Biosystems and Technology, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Maria Karlsson
- Microbial Horticulture, Department of Biosystems and Technology, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Elisabeth Uhlig
- Department of Food Technology, Engineering and Nutrition, Lund University, Lund, Sweden
| | - Åsa Håkansson
- Department of Food Technology, Engineering and Nutrition, Lund University, Lund, Sweden
| | - Beatrix Alsanius
- Microbial Horticulture, Department of Biosystems and Technology, Swedish University of Agricultural Sciences, Alnarp, Sweden
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Alegbeleye OO, Singleton I, Sant'Ana AS. Sources and contamination routes of microbial pathogens to fresh produce during field cultivation: A review. Food Microbiol 2018; 73:177-208. [PMID: 29526204 PMCID: PMC7127387 DOI: 10.1016/j.fm.2018.01.003] [Citation(s) in RCA: 245] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 12/31/2017] [Accepted: 01/02/2018] [Indexed: 12/17/2022]
Abstract
Foodborne illness resulting from the consumption of contaminated fresh produce is a common phenomenon and has severe effects on human health together with severe economic and social impacts. The implications of foodborne diseases associated with fresh produce have urged research into the numerous ways and mechanisms through which pathogens may gain access to produce, thereby compromising microbiological safety. This review provides a background on the various sources and pathways through which pathogenic bacteria contaminate fresh produce; the survival and proliferation of pathogens on fresh produce while growing and potential methods to reduce microbial contamination before harvest. Some of the established bacterial contamination sources include contaminated manure, irrigation water, soil, livestock/ wildlife, and numerous factors influence the incidence, fate, transport, survival and proliferation of pathogens in the wide variety of sources where they are found. Once pathogenic bacteria have been introduced into the growing environment, they can colonize and persist on fresh produce using a variety of mechanisms. Overall, microbiological hazards are significant; therefore, ways to reduce sources of contamination and a deeper understanding of pathogen survival and growth on fresh produce in the field are required to reduce risk to human health and the associated economic consequences.
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Affiliation(s)
| | - Ian Singleton
- School of Applied Sciences, Sighthill Campus, Edinburgh Napier University, Edinburgh, UK
| | - Anderson S Sant'Ana
- Department of Food Science, Faculty of Food Engineering, University of Campinas, Campinas, São Paulo, Brazil.
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31
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Lamas A, Regal P, Vázquez B, Miranda JM, Cepeda A, Franco CM. Salmonella and Campylobacter biofilm formation: a comparative assessment from farm to fork. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2018; 98:4014-4032. [PMID: 29424050 DOI: 10.1002/jsfa.8945] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 01/16/2018] [Accepted: 02/02/2018] [Indexed: 06/08/2023]
Abstract
It takes several steps to bring food from the farm to the fork (dining table), and contamination with food-borne pathogens can occur at any point in the process. Campylobacter spp. and Salmonella spp. are the main microorganisms responsible for foodborne disease in the EU. These two pathogens are able to persist throughout the food supply chain thanks to their ability to form biofilms. Owing to the high prevalence of Salmonella and especially of Campylobacter in the food supply chain and the huge efforts of food authorities to reduce these levels, it is of great importance to fully understand their mechanisms of persistence. Diverse studies have evaluated the biofilm-forming capacity of foodborne pathogens isolated at different steps of food production. Nonetheless, the principal obstacle of these studies is to reproduce the real conditions that microorganisms encounter in the food supply chain. While there are a wide number of Salmonella biofilm studies, information on Campylobacter biofilms is still limited. A comparison between the two microorganisms could help to develop new research in the field of Campylobacter biofilms. Therefore, this review evaluates relevant work in the field of Salmonella and Campylobacter biofilms and the applicability of the data obtained from these studies to real working conditions. © 2018 Society of Chemical Industry.
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Affiliation(s)
- Alexandre Lamas
- Laboratorio de Higiene Inspección y Control de Alimentos, Departamento de Química Analítica, Nutrición y Bromatología, Universidad de Santiago de Compostela, Lugo, Spain
| | - Patricia Regal
- Laboratorio de Higiene Inspección y Control de Alimentos, Departamento de Química Analítica, Nutrición y Bromatología, Universidad de Santiago de Compostela, Lugo, Spain
| | - Beatriz Vázquez
- Laboratorio de Higiene Inspección y Control de Alimentos, Departamento de Química Analítica, Nutrición y Bromatología, Universidad de Santiago de Compostela, Lugo, Spain
| | - José M Miranda
- Laboratorio de Higiene Inspección y Control de Alimentos, Departamento de Química Analítica, Nutrición y Bromatología, Universidad de Santiago de Compostela, Lugo, Spain
| | - Alberto Cepeda
- Laboratorio de Higiene Inspección y Control de Alimentos, Departamento de Química Analítica, Nutrición y Bromatología, Universidad de Santiago de Compostela, Lugo, Spain
| | - Carlos M Franco
- Laboratorio de Higiene Inspección y Control de Alimentos, Departamento de Química Analítica, Nutrición y Bromatología, Universidad de Santiago de Compostela, Lugo, Spain
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32
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Li D, Uyttendaele M. Potential of Human Norovirus Surrogates and Salmonella enterica Contamination of Pre-harvest Basil ( Ocimum basilicum) via Leaf Surface and Plant Substrate. Front Microbiol 2018; 9:1728. [PMID: 30105013 PMCID: PMC6077253 DOI: 10.3389/fmicb.2018.01728] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 07/11/2018] [Indexed: 12/14/2022] Open
Abstract
Fresh produce has been identified as an important vehicle for foodborne pathogen transmission and fresh culinary herbs have occasionally been associated with human pathogens and illness. In this study, the fate of human NoV surrogates [murine norovirus 1 (MNV-1) and Tulane virus (TV)] and three strains of Salmonella enterica on pre-harvest basil (Ocimum basilicum) was investigated. The persistence after contamination via either leaf surface or plant substrate was tested respectively. After 3 days, both MNV-1 and TV on pre-harvest leaves were at non-detectable levels (>5.5-log reduction for MNV-1 and >3.3-log reduction for TV). The three Salmonella strains showed consistent reductions of 3- to 4-log. At day 6 and 9, all the tested samples showed low levels of infectivity which were close or below the detection limits (1.7-log PFU/sample leaf for MNV-1 and TV, 0.7-log CFU/sample leaf for Salmonella) except for S. Thompson FMFP 899, one out of three samples showed to maintain present at exceptional high levels (day 6: 5.5-log CFU/sample leaf; day 9: 6.7-log CFU/sample leaf). Possibilities of microbial internalization into the edible parts of basil via the roots was demonstrated with both MNV-1 and S. enterica Thompson FMFP 899. The infectivity of internalized MNV-1 and S. enterica both decreased to non-detectable levels within 9 days after inoculation. Moreover, it should be noticed that very high microbial inoculation was used in the experimental set-up (8.46-log PFU/ml of MNV-1, 8.60-log CFU/ml of S. enterica), which is abnormal in the real-life expected contamination scenario. Within the tested scenarios in this study, S. enterica contaminated on the adaxial leaf surface of basil plants while in growth, and remained/reached a high population of over 6-log CFU/sample leaf after 9 days in one out of three samples, thus showed the highest potential for causing foodborne infection.
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Affiliation(s)
- Dan Li
- Food Microbiology and Food Preservation Research Unit, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
- Food Science and Technology Programme, Department of Chemistry, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - 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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Liu H, Whitehouse CA, Li B. Presence and Persistence of Salmonella in Water: The Impact on Microbial Quality of Water and Food Safety. Front Public Health 2018; 6:159. [PMID: 29900166 PMCID: PMC5989457 DOI: 10.3389/fpubh.2018.00159] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 05/10/2018] [Indexed: 01/23/2023] Open
Abstract
Salmonella ranks high among the pathogens causing foodborne disease outbreaks. According to the Centers for Disease Control and Prevention, Salmonella contributed to about 53.4% of all foodborne disease outbreaks from 2006 to 2017, and approximately 32.7% of these foodborne Salmonella outbreaks were associated with consumption of produce. Trace-back investigations have suggested that irrigation water may be a source of Salmonella contamination of produce and a vehicle for transmission. Presence and persistence of Salmonella have been reported in surface waters such as rivers, lakes, and ponds, while ground water in general offers better microbial quality for irrigation. To date, culture methods are still the gold standard for detection, isolation and identification of Salmonella in foods and water. In addition to culture, other methods for the detection of Salmonella in water include most probable number, immunoassay, and PCR. The U.S. Food and Drug Administration (FDA) issued the Produce Safety Rule (PSR) in January 2013 based on the Food Safety Modernization Act (FSMA), which calls for more efforts toward enhancing and improving approaches for the prevention of foodborne outbreaks. In the PSR, agricultural water is defined as water used for in a way that is intended to, or likely to, contact covered produce, such as spray, wash, or irrigation. In summary, Salmonella is frequently present in surface water, an important source of water for irrigation. An increasing evidence indicates irrigation water as a source (or a vehicle) for transmission of Salmonella. This pathogen can survive in aquatic environments by a number of mechanisms, including entry into the viable but nonculturable (VBNC) state and/or residing within free-living protozoa. As such, assurance of microbial quality of irrigation water is critical to curtail the produce-related foodborne outbreaks and thus enhance the food safety. In this review, we will discuss the presence and persistence of Salmonella in water and the mechanisms Salmonella uses to persist in the aquatic environment, particularly irrigation water, to better understand the impact on the microbial quality of water and food safety due to the presence of Salmonella in the water environment.
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Affiliation(s)
- Huanli Liu
- Branch of Microbiology, Arkansas Laboratory, Office of Regulatory Affairs, United States Food and Drug Administration, Jefferson, AR, United States
| | - Chris A. Whitehouse
- Division of Molecular Biology, Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, Laurel, MD, United States
| | - Baoguang Li
- Division of Molecular Biology, Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, Laurel, MD, United States
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De Abrew Abeysundara P, Dhowlaghar N, Nannapaneni R, Schilling MW, Mahmoud B, Sharma CS, Ma DP. Salmonella enterica growth and biofilm formation in flesh and peel cantaloupe extracts on four food-contact surfaces. Int J Food Microbiol 2018; 280:17-26. [PMID: 29763755 DOI: 10.1016/j.ijfoodmicro.2018.04.042] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/26/2018] [Accepted: 04/30/2018] [Indexed: 11/29/2022]
Abstract
Salmonella enterica is responsible for the highest number of foodborne disease outbreaks pertaining to cantaloupe industry. The objective of this study was to examine the growth and biofilm formation by outbreak strains of S. enterica ser. Poona (S. Poona), S. enterica ser. Stanley (S. Stanley) and S. enterica ser. Montevideo (S. Montevideo) on different food-contact processing surfaces in cantaloupe flesh and peel extracts at 22 °C and 10 °C. The generation time of all S. enterica strains tested was shorter in the high concentration (50 mg/ml) of cantaloupe extract and high temperature. In 50 mg/ml of cantaloupe flesh or peel extract, the populations of S. enterica were increased by 5 log CFU/ml in 24 h at 22 °C and 1 log CFU/ml in 72 h at 10 °C. In 2 mg/ml of cantaloupe flesh or peel extracts, the populations of S. enterica were increased by 3.5 log CFU/ml in 56 h at 22 °C, but there were no changes in 72 h at 10 °C. The biofilm production of S. enterica was greater at 50 mg/ml of cantaloupe extract and 22 °C, but no major differences (P ≥ 0.05) were found among the strains tested. In 50 mg/ml cantaloupe extract, S. enterica produced 5-6 log CFU/cm2 biofilm in 4-7 d at 22 °C and approximately 3.5-4 log CFU/cm2 in 7 d at 10 °C. In 2 mg/ml of cantaloupe extract, S. enterica produced 4-4.5 log CFU/cm2 biofilms in 4-7 d at 22 °C and 3 log CFU/cm2 in 7 d at 10 °C. Biofilm formation by S. Poona (01A4754) was lowest on buna-n rubber compared to stainless steel, polyethylene and polyurethane surfaces under the majority of conditions tested. Overall, these findings show that S. enterica strains can grow rapidly and form biofilms on different cantaloupe processing surfaces in the presence of low concentrations of cantaloupe flesh or peel extracts.
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Affiliation(s)
- Piumi De Abrew Abeysundara
- Department of Food Science, Nutrition and Health Promotion, Mississippi State University, Mississippi State, MS 39762, USA
| | - Nitin Dhowlaghar
- Department of Food Science, Nutrition and Health Promotion, Mississippi State University, Mississippi State, MS 39762, USA
| | - Ramakrishna Nannapaneni
- Department of Food Science, Nutrition and Health Promotion, Mississippi State University, Mississippi State, MS 39762, USA.
| | - Mark W Schilling
- Department of Food Science, Nutrition and Health Promotion, Mississippi State University, Mississippi State, MS 39762, USA
| | - Barakat Mahmoud
- Department of Food Science, Nutrition and Health Promotion, Mississippi State University, Mississippi State, MS 39762, USA
| | - Chander S Sharma
- Poultry Science Department, Mississippi State University, Mississippi State, MS 39762, USA
| | - Din-Pow Ma
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Mississippi State, MS 39762, USA
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35
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Biofilm formation by Salmonella spp. in catfish mucus extract under industrial conditions. Food Microbiol 2018; 70:172-180. [DOI: 10.1016/j.fm.2017.09.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 08/22/2017] [Accepted: 09/23/2017] [Indexed: 11/18/2022]
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36
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Perez-Lewis KL, Yegin Y, Cisneros-Zevallos L, Castillo A, Kerth CR, Akbulut M, Taylor TM. Geraniol-Loaded Polymeric Nanoparticles Inhibit Enteric Pathogens on Spinach during Posttreatment Refrigerated and Temperature Abuse Storage. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2018. [DOI: 10.3389/fsufs.2018.00004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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37
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Iliadis I, Daskalopoulou A, Simões M, Giaouris E. Integrated combined effects of temperature, pH and sodium chloride concentration on biofilm formation by Salmonella enterica ser. Enteritidis and Typhimurium under low nutrient food-related conditions. Food Res Int 2018; 107:10-18. [PMID: 29580466 DOI: 10.1016/j.foodres.2018.02.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Revised: 02/02/2018] [Accepted: 02/03/2018] [Indexed: 01/03/2023]
Abstract
Salmonella enterica is a major foodborne bacterial pathogen. This forms biofilms on surfaces and persists, depending on the strain and the environment. The integrative interaction of temperature (T; 13-39 °C), pH (5-8) and sodium chloride (NaCl) concentration (0.5-8.5%) on biofilm formation by two S. enterica strains (ser. Enteritidis and Typhimurium) was here evaluated under low nutrient conditions. This was achieved using response surface methodology to model the combined effect of each factor on the response, through mathematical quadratic fitting of the outcomes of a sequence of designed experiments. These last were executed by incubating stainless steel coupons carrying sessile bacteria, for 24 h, in 1:10 diluted tryptone soya broth, under 15 different combinations of three independent factors (T, pH and NaCl). For each strain, a second order polynomial model, describing the relationship between biofilm formation (log CFU/cm2) and the factors (T, pH and NaCl), was developed using least square regression analysis. Both derived models predicted the combined influences of these factors on biofilm formation, with agreement between predictions and experimental observations (R2 ≥ 0.96, P ≤ 0.0001). For both strains, the increase of NaCl content restricted their sessile growth, while under low salinity conditions (NaCl < 4%) biofilm formation was favored as pH increased, regardless of T. Interestingly, under low salt content, and depending on the strain, biofilm formation was either favored or hindered by increasing T. Thus, 34.5 and 13 °C were the T predicted to maximize biofilm formation by strains Enteritidis and Typhimurium, respectively, something which was also experimentally verified. To sum, these models can predict the interactive influences of crucial food-related factors on biofilm growth of a significant foodborne pathogen towards the efforts to limit its persistence in food industry.
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Affiliation(s)
- Ioannis Iliadis
- Department of Food Science and Nutrition, Faculty of the Environment, University of the Aegean, Mitropoliti Ioakeim 2, 81400 Myrina, Lemnos, Greece
| | - Aikaterini Daskalopoulou
- Department of Food Science and Nutrition, Faculty of the Environment, University of the Aegean, Mitropoliti Ioakeim 2, 81400 Myrina, Lemnos, Greece
| | - Manuel Simões
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal
| | - Efstathios Giaouris
- Department of Food Science and Nutrition, Faculty of the Environment, University of the Aegean, Mitropoliti Ioakeim 2, 81400 Myrina, Lemnos, Greece.
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38
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Han R, Klu YAK, Chen J. Attachment and Biofilm Formation by Selected Strains of
Salmonella enterica
and Entrohemorrhagic
Escherichia coli
of Fresh Produce Origin. J Food Sci 2017; 82:1461-1466. [DOI: 10.1111/1750-3841.13722] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 03/09/2017] [Accepted: 03/29/2017] [Indexed: 11/26/2022]
Affiliation(s)
- Ran Han
- Dept. of Food Science and Technology The Univ. of Georgia 1109 Experiment Street Griffin GA 30223 U.S.A
| | - Yaa Asantewaa Kafui Klu
- Dept. of Food Science and Technology The Univ. of Georgia 1109 Experiment Street Griffin GA 30223 U.S.A
| | - Jinru Chen
- Dept. of Food Science and Technology The Univ. of Georgia 1109 Experiment Street Griffin GA 30223 U.S.A
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39
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Tan MSF, Rahman S, Dykes GA. Sonication reduces the attachment of Salmonella Typhimurium ATCC 14028 cells to bacterial cellulose-based plant cell wall models and cut plant material. Food Microbiol 2017; 62:62-67. [PMID: 27889167 DOI: 10.1016/j.fm.2016.10.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 06/30/2016] [Accepted: 10/02/2016] [Indexed: 11/19/2022]
Abstract
This study investigated the removal of bacterial surface structures, particularly flagella, using sonication, and examined its effect on the attachment of Salmonella Typhimurium ATCC 14028 cells to plant cell walls. S. Typhimurium ATCC 14028 cells were subjected to sonication at 20 kHz to remove surface structures without affecting cell viability. Effective removal of flagella was determined by staining flagella of sonicated cells with Ryu's stain and enumerating the flagella remaining by direct microscopic counting. The attachment of sonicated S. Typhimurium cells to bacterial cellulose-based plant cell wall models and cut plant material (potato, apple, lettuce) was then evaluated. Varying concentrations of pectin and/or xyloglucan were used to produce a range of bacterial cellulose-based plant cell wall models. As compared to the non-sonicated controls, sonicated S. Typhimurium cells attached in significantly lower numbers (between 0.5 and 1.0 log CFU/cm2) to all surfaces except to the bacterial cellulose-only composite without pectin and xyloglucan. Since attachment of S. Typhimurium to the bacterial cellulose-only composite was not affected by sonication, this suggests that bacterial surface structures, particularly flagella, could have specific interactions with pectin and xyloglucan. This study indicates that sonication may have potential applications for reducing Salmonella attachment during the processing of fresh produce.
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Affiliation(s)
- Michelle S F Tan
- School of Science, Monash University, Jalan Lagoon Selatan, Bandar Sunway, 46150 Selangor, Malaysia
| | - Sadequr Rahman
- School of Science, Monash University, Jalan Lagoon Selatan, Bandar Sunway, 46150 Selangor, Malaysia
| | - Gary A Dykes
- School of Public Health, Curtin University, Perth, 6845 Western Australia, Australia.
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40
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Mesarich CH, Rees-George J, Gardner PP, Ghomi FA, Gerth ML, Andersen MT, Rikkerink EHA, Fineran PC, Templeton MD. Transposon insertion libraries for the characterization of mutants from the kiwifruit pathogen Pseudomonas syringae pv. actinidiae. PLoS One 2017; 12:e0172790. [PMID: 28249011 PMCID: PMC5332098 DOI: 10.1371/journal.pone.0172790] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Accepted: 02/09/2017] [Indexed: 01/15/2023] Open
Abstract
Pseudomonas syringae pv. actinidiae (Psa), the causal agent of kiwifruit canker, is one of the most devastating plant diseases of recent times. We have generated two mini-Tn5-based random insertion libraries of Psa ICMP 18884. The first, a 'phenotype of interest' (POI) library, consists of 10,368 independent mutants gridded into 96-well plates. By replica plating onto selective media, the POI library was successfully screened for auxotrophic and motility mutants. Lipopolysaccharide (LPS) biosynthesis mutants with 'Fuzzy-Spreader'-like morphologies were also identified through a visual screen. The second, a 'mutant of interest' (MOI) library, comprises around 96,000 independent mutants, also stored in 96-well plates, with approximately 200 individuals per well. The MOI library was sequenced on the Illumina MiSeq platform using Transposon-Directed Insertion site Sequencing (TraDIS) to map insertion sites onto the Psa genome. A grid-based PCR method was developed to recover individual mutants, and using this strategy, the MOI library was successfully screened for a putative LPS mutant not identified in the visual screen. The Psa chromosome and plasmid had 24,031 and 1,236 independent insertion events respectively, giving insertion frequencies of 3.65 and 16.6 per kb respectively. These data suggest that the MOI library is near saturation, with the theoretical probability of finding an insert in any one chromosomal gene estimated to be 97.5%. However, only 47% of chromosomal genes had insertions. This surprisingly low rate cannot be solely explained by the lack of insertions in essential genes, which would be expected to be around 5%. Strikingly, many accessory genes, including most of those encoding type III effectors, lacked insertions. In contrast, 94% of genes on the Psa plasmid had insertions, including for example, the type III effector HopAU1. These results suggest that some chromosomal sites are rendered inaccessible to transposon insertion, either by DNA-binding proteins or by the architecture of the nucleoid.
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Affiliation(s)
- Carl H. Mesarich
- Bioprotection Portfolio, The New Zealand Institute for Plant & Food Research Limited, Auckland, New Zealand
- Laboratory of Molecular Plant Pathology, Institute of Agriculture and Environment, Massey University, Palmerston North, New Zealand
- Bio-Protection Research Centre, New Zealand
| | - Jonathan Rees-George
- Bioprotection Portfolio, The New Zealand Institute for Plant & Food Research Limited, Auckland, New Zealand
| | - Paul P. Gardner
- Bio-Protection Research Centre, New Zealand
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Fatemeh Ashari Ghomi
- Bio-Protection Research Centre, New Zealand
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Monica L. Gerth
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Mark T. Andersen
- Bioprotection Portfolio, The New Zealand Institute for Plant & Food Research Limited, Auckland, New Zealand
| | - Erik H. A. Rikkerink
- Bioprotection Portfolio, The New Zealand Institute for Plant & Food Research Limited, Auckland, New Zealand
| | - Peter C. Fineran
- Bio-Protection Research Centre, New Zealand
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Matthew D. Templeton
- Bioprotection Portfolio, The New Zealand Institute for Plant & Food Research Limited, Auckland, New Zealand
- Bio-Protection Research Centre, New Zealand
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
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41
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Ximenes E, Hoagland L, Ku S, Li X, Ladisch M. Human pathogens in plant biofilms: Formation, physiology, and detection. Biotechnol Bioeng 2017; 114:1403-1418. [PMID: 28067424 DOI: 10.1002/bit.26247] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 01/05/2017] [Accepted: 01/05/2017] [Indexed: 12/29/2022]
Affiliation(s)
- Eduardo Ximenes
- Laboratory of Renewable Resources Engineering; Purdue University; West Lafayette Indiana 47907-2022
- Department of Agricultural and Biological Engineering; Purdue University; West Lafayette Indiana
| | - Lori Hoagland
- Horticulture and Landscape Architecture; Purdue University; West Lafayette Indiana
| | - Seockmo Ku
- Laboratory of Renewable Resources Engineering; Purdue University; West Lafayette Indiana 47907-2022
- Department of Agricultural and Biological Engineering; Purdue University; West Lafayette Indiana
| | - Xuan Li
- Laboratory of Renewable Resources Engineering; Purdue University; West Lafayette Indiana 47907-2022
| | - Michael Ladisch
- Laboratory of Renewable Resources Engineering; Purdue University; West Lafayette Indiana 47907-2022
- Department of Agricultural and Biological Engineering; Purdue University; West Lafayette Indiana
- Weldon School of Biomedical Engineering; Purdue University; West Lafayette Indiana
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42
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Tomita K, Sawai J. Preincubation of Escherichia coli ATCC 25922 with NaCl Increases Its Attachment to Lettuce Surfaces Compared with Other Chemicals. Biocontrol Sci 2017; 22:137-143. [PMID: 28954956 DOI: 10.4265/bio.22.137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
The inhibition of microbial attachment to food is important for the prevention of cross-contamination during food processing. The effect of several chemicals that were added in an Escherichia coli growth medium on the attachment of the bacterium to lettuce was investigated. E. coli ATCC 25922, which is reportedly a useful surrogate for E. coli O157:H7 in surface attachment studies, was preincubated in a nutrient broth (NB) containing sodium chloride, potassium chloride, sodium deoxycholate, sodium linear alkylbenzene sulfonate, or sorbic acid. The bacterial cells were placed in contact with cut lettuce in a saline solution at 5℃ for 24 hours. Only the addition of NaCl in the NB influenced the attachment of E. coli, Salmonella enterica subsp. Enteritidis, and Klebsiella pneumoniae to the lettuce. The attachment of E. coli showed the largest significant increase at 2% NaCl. Changes in the attachment levels were not due to surface hydrohobicity or the motility of E. coli cells. Similar results were observed for S. enterica although the variation in the degree of attachment of the latter was quite small. These results suggested that the attachment of E. coli O157:H7 to food surfaces is influenced by the bacterial growth conditions prior to food exposure and prior to the development of the biofilm; furthermore, the environmental NaCl concentration should be controlled during food processing to prevent the cross-contamination of foods with E. coli.
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Affiliation(s)
- Kazuhisa Tomita
- Faculty of Applied Bioscience, Kanagawa Institute of Technology
| | - Jun Sawai
- Faculty of Applied Bioscience, Kanagawa Institute of Technology
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43
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Van der Linden I, Avalos Llano KR, Eriksson M, De Vos WH, Van Damme EJM, Uyttendaele M, Devlieghere F. Minimal processing of iceberg lettuce has no substantial influence on the survival, attachment and internalization of E. coli O157 and Salmonella. Int J Food Microbiol 2016; 238:40-49. [PMID: 27591385 DOI: 10.1016/j.ijfoodmicro.2016.07.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 06/17/2016] [Accepted: 07/24/2016] [Indexed: 10/21/2022]
Abstract
The influence of a selection of minimal processing techniques (sanitizing wash prior to packaging, modified atmosphere, storage conditions under light or in the dark) was investigated in relation to the survival of, attachment to and internalization of enteric pathogens in fresh produce. Cut Iceberg lettuce was chosen as a model for fresh produce, Escherichia coli O157:H7 (E. coli O157) and Salmonella enterica were chosen as pathogen models. Care was taken to simulate industrial post-harvest processing. A total of 50±0.1g of fresh-cut Iceberg lettuce was packed in bags under near ambient atmospheric air with approximately 21% O2 (NAA) conditions or equilibrium modified atmosphere with 3% O2 (EMAP). Two lettuce pieces inoculated with E. coli O157 BRMSID 188 or Salmonella Typhimurium labeled with green fluorescent protein (GFP) were added to each package. The bags with cut lettuce were stored under either dark or light conditions for 2days at 7°C. The pathogens' capacity to attach to the lettuce surface and cut edge was evaluated 2days after inoculation using conventional plating technique and the internalization of the bacteria was investigated and quantified using confocal microscopy. The effect of a sanitizing wash step (40mg/L NaClO or 40mg/L peracetic acid+1143mg/L lactic acid) of the cut lettuce prior to packaging was evaluated as well. Our results indicate that both pathogens behaved similarly under the investigated conditions. Pathogen growth was not observed, nor was there any substantial influence of the investigated atmospheric conditions or light/dark storage conditions on their attachment/internalization. The pathogens attached to and internalized via cut edges and wounds, from which they were able to penetrate into the parenchyma. Internalization through the stomata into the parenchyma was not observed, although some bacteria were found in the substomatal cavity. Washing the cut edges with sanitizing agents to reduce enteric pathogen numbers was not more effective than a rinse with precooled tap water prior to packaging. Our results confirm that cut surfaces are the main risk for postharvest attachment and internalization of E. coli O157 and Salmonella during minimal processing and that storage and packaging conditions have no important effect.
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Affiliation(s)
- Inge Van der Linden
- Ghent University (UGent), Faculty of Bioscience Engineering, Department of Food Safety and Food Quality, Laboratory of Food Microbiology and Food Preservation, Coupure links 653, B-9000 Ghent, Belgium.
| | - Karina R Avalos Llano
- Ghent University (UGent), Faculty of Bioscience Engineering, Department of Food Safety and Food Quality, Laboratory of Food Microbiology and Food Preservation, Coupure links 653, B-9000 Ghent, Belgium.
| | - Markus Eriksson
- Ghent University (UGent), Faculty of Bioscience Engineering, Department of Food Safety and Food Quality, Laboratory of Food Microbiology and Food Preservation, Coupure links 653, B-9000 Ghent, Belgium.
| | - Winnok H De Vos
- Ghent University (UGent), Faculty of Bioscience Engineering, Department of Molecular Biotechnology, Coupure links 653, B-9000 Ghent, Belgium; University of Antwerp, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Department of Veterinary Sciences, Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
| | - Els J M Van Damme
- Ghent University (UGent), Faculty of Bioscience Engineering, Department of Molecular Biotechnology, Coupure links 653, B-9000 Ghent, Belgium.
| | - Mieke Uyttendaele
- Ghent University (UGent), Faculty of Bioscience Engineering, Department of Food Safety and Food Quality, Laboratory of Food Microbiology and Food Preservation, Coupure links 653, B-9000 Ghent, Belgium.
| | - Frank Devlieghere
- Ghent University (UGent), Faculty of Bioscience Engineering, Department of Food Safety and Food Quality, Laboratory of Food Microbiology and Food Preservation, Coupure links 653, B-9000 Ghent, Belgium.
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44
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Faour-Klingbeil D, Kuri V, Todd E. The transfer rate of Salmonella Typhimurium from contaminated parsley to other consecutively chopped batches via cutting boards under different food handling scenarios. Food Res Int 2016; 89:495-503. [DOI: 10.1016/j.foodres.2016.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 08/15/2016] [Accepted: 09/01/2016] [Indexed: 10/21/2022]
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45
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Tan MSF, Moore SC, Tabor RF, Fegan N, Rahman S, Dykes GA. Attachment of Salmonella strains to a plant cell wall model is modulated by surface characteristics and not by specific carbohydrate interactions. BMC Microbiol 2016; 16:212. [PMID: 27629769 PMCID: PMC5024418 DOI: 10.1186/s12866-016-0832-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Indexed: 12/04/2022] Open
Abstract
Background Processing of fresh produce exposes cut surfaces of plant cell walls that then become vulnerable to human foodborne pathogen attachment and contamination, particularly by Salmonella enterica. Plant cell walls are mainly composed of the polysaccharides cellulose, pectin and hemicelluloses (predominantly xyloglucan). Our previous work used bacterial cellulose-based plant cell wall models to study the interaction between Salmonella and the various plant cell wall components. We demonstrated that Salmonella attachment was favoured in the presence of pectin while xyloglucan had no effect on its attachment. Xyloglucan significantly increased the attachment of Salmonella cells to the plant cell wall model only when it was in association with pectin. In this study, we investigate whether the plant cell wall polysaccharides mediate Salmonella attachment to the bacterial cellulose-based plant cell wall models through specific carbohydrate interactions or through the effects of carbohydrates on the physical characteristics of the attachment surface. Results We found that none of the monosaccharides that make up the plant cell wall polysaccharides specifically inhibit Salmonella attachment to the bacterial cellulose-based plant cell wall models. Confocal laser scanning microscopy showed that Salmonella cells can penetrate and attach within the tightly arranged bacterial cellulose network. Analysis of images obtained from atomic force microscopy revealed that the bacterial cellulose-pectin-xyloglucan composite with 0.3 % (w/v) xyloglucan, previously shown to have the highest number of Salmonella cells attached to it, had significantly thicker cellulose fibrils compared to other composites. Scanning electron microscopy images also showed that the bacterial cellulose and bacterial cellulose-xyloglucan composites were more porous when compared to the other composites containing pectin. Conclusions Our study found that the attachment of Salmonella cells to cut plant cell walls was not mediated by specific carbohydrate interactions. This suggests that the attachment of Salmonella strains to the plant cell wall models were more dependent on the structural characteristics of the attachment surface. Pectin reduces the porosity and space between cellulose fibrils, which then forms a matrix that is able to retain Salmonella cells within the bacterial cellulose network. When present with pectin, xyloglucan provides a greater surface for Salmonella cells to attach through the thickening of cellulose fibrils.
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Affiliation(s)
- Michelle Sze-Fan Tan
- School of Science, Monash University Malaysia, Jalan Lagoon Selatan, 47500, Bandar Sunway, Selangor Darul Ehsan, Malaysia
| | - Sean C Moore
- CSIRO Agriculture and Food, 671 Sneydes Road, Werribee, VIC, 3030, Australia
| | - Rico F Tabor
- School of Chemistry, Monash University, Clayton campus, Wellington Road, Clayton, VIC, 3800, Australia
| | - Narelle Fegan
- CSIRO Agriculture and Food, 671 Sneydes Road, Werribee, VIC, 3030, Australia
| | - Sadequr Rahman
- School of Science, Monash University Malaysia, Jalan Lagoon Selatan, 47500, Bandar Sunway, Selangor Darul Ehsan, Malaysia
| | - Gary A Dykes
- School of Public Health, Curtin University, Perth, WA, 6845, Australia.
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46
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Biofilm Formation by Environmental Isolates of Salmonella and Their Sensitivity to Natural Antimicrobials. Foodborne Pathog Dis 2016; 13:509-16. [DOI: 10.1089/fpd.2016.2145] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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47
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Sze-Fan Tan M, Rahman S, Dykes GA. Relationship between cell concentration and Salmonella attachment to plant cell walls. Food Control 2016. [DOI: 10.1016/j.foodcont.2016.02.039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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48
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Faour-Klingbeil D, Kuri V, Todd EC. The influence of pre-wash chopping and storage conditions of parsley on the efficacy of disinfection against S. Typhimurium. Food Control 2016. [DOI: 10.1016/j.foodcont.2016.01.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/01/2022]
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49
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Tan MSF, White AP, Rahman S, Dykes GA. Role of Fimbriae, Flagella and Cellulose on the Attachment of Salmonella Typhimurium ATCC 14028 to Plant Cell Wall Models. PLoS One 2016; 11:e0158311. [PMID: 27355584 PMCID: PMC4927157 DOI: 10.1371/journal.pone.0158311] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 06/14/2016] [Indexed: 12/29/2022] Open
Abstract
Cases of foodborne disease caused by Salmonella are frequently associated with the consumption of minimally processed produce. Bacterial cell surface components are known to be important for the attachment of bacterial pathogens to fresh produce. The role of these extracellular structures in Salmonella attachment to plant cell walls has not been investigated in detail. We investigated the role of flagella, fimbriae and cellulose on the attachment of Salmonella Typhimurium ATCC 14028 and a range of isogenic deletion mutants (ΔfliC fljB, ΔbcsA, ΔcsgA, ΔcsgA bcsA and ΔcsgD) to bacterial cellulose (BC)-based plant cell wall models [BC-Pectin (BCP), BC-Xyloglucan (BCX) and BC-Pectin-Xyloglucan (BCPX)] after growth at different temperatures (28°C and 37°C). We found that all three cell surface components were produced at 28°C but only the flagella was produced at 37°C. Flagella appeared to be most important for attachment (reduction of up to 1.5 log CFU/cm2) although both cellulose and fimbriae also aided in attachment. The csgD deletion mutant, which lacks both cellulose and fimbriae, showed significantly higher attachment as compared to wild type cells at 37°C. This may be due to the increased expression of flagella-related genes which are also indirectly regulated by the csgD gene. Our study suggests that bacterial attachment to plant cell walls is a complex process involving many factors. Although flagella, cellulose and fimbriae all aid in attachment, these structures are not the only mechanism as no strain was completely defective in its attachment.
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Affiliation(s)
| | - Aaron P. White
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Sadequr Rahman
- School of Science, Monash University, Bandar Sunway, Selangor, Malaysia
| | - Gary A. Dykes
- School of Public Health, Curtin University, Perth, Western Australia, Australia
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50
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Yang Y, Mikš-Krajnik M, Zheng Q, Lee SB, Lee SC, Yuk HG. Biofilm formation of Salmonella Enteritidis under food-related environmental stress conditions and its subsequent resistance to chlorine treatment. Food Microbiol 2016. [DOI: 10.1016/j.fm.2015.10.010] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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