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Seyfferth AL, Limmer MA, Runkle BRK, Chaney RL. Mitigating Toxic Metal Exposure Through Leafy Greens: A Comprehensive Review Contrasting Cadmium and Lead in Spinach. GEOHEALTH 2024; 8:e2024GH001081. [PMID: 38887469 PMCID: PMC11181011 DOI: 10.1029/2024gh001081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 05/21/2024] [Accepted: 05/21/2024] [Indexed: 06/20/2024]
Abstract
Metals and metalloids (hereafter, metal(loid)s) in plant-based foods are a source of exposure to humans, but not all metal(loid)-food interactions are the same. Differences exist between metal(loid)s in terms of their behavior in soils and in how they are taken up by plants and stored in the edible plant tissue/food. Thus, there cannot be one consistent solution to reducing toxic metal(loid)s exposure to humans from foods. In addition, how metal(loid)s are absorbed, distributed, metabolized, and excreted by the human body differs based on both the metal(loid), other elements and nutrients in the food, and the nutritional status of the human. Initiatives like the United States Food and Drug Administration's Closer to Zero initiative to reduce the exposure of young children to the toxic elements cadmium, lead, arsenic, and mercury from foods warrant careful consideration of each metal(loid) and plant interaction. This review explores such plant-metal(loid) interactions using the example of spinach and the metals cadmium and lead. This review highlights differences in the magnitude of exposure, bioavailability, and the practicality of mitigation strategies while outlining research gaps and future needs. A focus on feasibility and producer needs, informed via stakeholder interviews, emphasizes the need for better analytical testing facilities and grower and consumer education. More research should focus on minimization of chloride inputs for leafy greens to lessen plant-availability of Cd and the role of oxalate in reducing Cd bioavailability from spinach. These findings are applicable to other leafy greens (e.g., kale, lettuce), but not for other plants or metal(loid)s.
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Affiliation(s)
| | - Matt A. Limmer
- Department of Plant and Soil SciencesUniversity of DelawareNewarkDEUSA
| | - Benjamin R. K. Runkle
- Department of Biological and Agricultural EngineeringUniversity of ArkansasFayettevilleARUSA
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Ding Q, Gu G, Nou X, Micallef SA. Cultivar was more influential than bacterial strain and other experimental factors in recovery of Escherichia coli O157:H7 populations from inoculated live Romaine lettuce plants. Microbiol Spectr 2024; 12:e0376723. [PMID: 38363139 PMCID: PMC10986467 DOI: 10.1128/spectrum.03767-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 01/22/2024] [Indexed: 02/17/2024] Open
Abstract
The varied choice of bacterial strain, plant cultivar, and method used to inoculate, retrieve, and enumerate Escherichia coli O157:H7 from live plants could affect comparability among studies evaluating lettuce-enterobacterial interactions. Cultivar, bacterial strain, incubation time, leaf side inoculated, and sample processing method were assessed for their influence in recovering and quantifying E. coli O157:H7 from live Romaine lettuce. Cultivar exerted the strongest effect on E. coli O157:H7 counts, which held up even when cultivar was considered in interactions with other factors. Recovery from the popularly grown green Romaine "Rio Bravo" was higher than from the red variety "Outredgeous." Other modulating variables were incubation time, strain, and leaf side inoculated. Sample processing method was not significant. Incubation for 24 hours post-lettuce inoculation yielded greater counts than 48 hours, but was affected by lettuce cultivar, bacterial strain, and leaf side inoculated. Higher counts obtained for strain EDL933 compared to a lettuce outbreak strain 2705C emphasized the importance of selecting relevant strains for the system being studied. Inoculating the abaxial side of leaves gave higher counts than adaxial surface inoculation, although this factor interacted with strain and incubation period. Our findings highlight the importance of studying interactions between appropriate bacterial strains and plant cultivars for more relevant research results, and of standardizing inoculation and incubation procedures. The strong effect of cultivar exerted on the E. coli O157:H7-lettuce association supports the need to start reporting cultivar information for illness outbreaks to facilitate the identification and study of plant traits that impact food safety risk.IMPORTANCEThe contamination of Romaine lettuce with Escherichia coli O157:H7 has been linked to multiple foodborne disease outbreaks, but variability in the methods used to evaluate E. coli O157:H7 association with live lettuce plants complicates the comparability of different studies. In this study, various experimental variables and sample processing methods for recovering and quantifying E. coli O157:H7 from live Romaine lettuce were assessed. Cultivar was found to exert the strongest influence on E. coli O157:H7 retrieval from lettuce. Other modulating factors were bacterial incubation time on plants, strain, and leaf side inoculated, while sample processing method had no impact. Our findings highlight the importance of selecting relevant cultivars and strains, and of standardizing inoculation and incubation procedures, in these types of assessments. Moreover, results support the need to start reporting cultivars implicated in foodborne illness outbreaks to facilitate the identification and study of plant traits that impact food safety risk.
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Affiliation(s)
- Qiao Ding
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, Maryland, USA
| | - Ganyu Gu
- Environmental Microbial and Food Safety Laboratory, USDA ARS, Beltsville, Maryland, USA
| | - Xiangwu Nou
- Environmental Microbial and Food Safety Laboratory, USDA ARS, Beltsville, Maryland, USA
| | - Shirley A. Micallef
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, Maryland, USA
- Center for Food Safety and Security Systems, University of Maryland, College Park, Maryland, USA
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Topalcengiz Z, Chandran S, Gibson KE. A comprehensive examination of microbial hazards and risks during indoor soilless leafy green production. Int J Food Microbiol 2024; 411:110546. [PMID: 38157635 DOI: 10.1016/j.ijfoodmicro.2023.110546] [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: 08/14/2023] [Revised: 10/26/2023] [Accepted: 12/16/2023] [Indexed: 01/03/2024]
Abstract
Produce grown under controlled environment agriculture (CEA) is often assumed to have a reduced risk of pathogen contamination due to the low chance of exposure to outdoor contaminant factors. However, the 2021 outbreak and numerous recalls of CEA-grown lettuce and microgreens demonstrate the possibility of pathogen introduction during indoor production when there is a failure in the implementation of food safety management systems. Indoor production of commercial leafy greens, such as lettuce and microgreens, is performed across a range of protective structures from primitive household setups to advanced and partially automatized growing systems. Indoor production systems include hydroponic, aquaponic, and aeroponic configurations. Hydroponic systems such as deep water culture and nutrient film technique comprised of various engineering designs represent the main system types used by growers. Depending on the type of leafy green, the soilless substrate, and system selection, risk of microbial contamination will vary during indoor production. In this literature review, science-based pathogen contamination risks and mitigation strategies for indoor production of microgreens and more mature leafy greens are discussed during both pre-harvest and post-harvest stages of production.
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Affiliation(s)
- Zeynal Topalcengiz
- Department of Food Science, Center for Food Safety, University of Arkansas System Division of Agriculture, Fayetteville, AR 72704, USA; Department of Food Engineering, Faculty of Engineering and Architecture, Muş Alparslan University, 49250 Muş, Türkiye
| | - Sahaana Chandran
- Department of Food Science, Center for Food Safety, University of Arkansas System Division of Agriculture, Fayetteville, AR 72704, USA
| | - Kristen E Gibson
- Department of Food Science, Center for Food Safety, University of Arkansas System Division of Agriculture, Fayetteville, AR 72704, USA.
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Pimentel C, Pina CM, Müller N, Lara LA, Melo Rodriguez G, Orlando F, Schoelkopf J, Fernández V. Mineral Particles in Foliar Fertilizer Formulations Can Improve the Rate of Foliar Uptake. PLANTS (BASEL, SWITZERLAND) 2023; 13:71. [PMID: 38202379 PMCID: PMC10780703 DOI: 10.3390/plants13010071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 12/19/2023] [Accepted: 12/20/2023] [Indexed: 01/12/2024]
Abstract
The application of foliar sprays of suspensions of relatively insoluble essential element salts is gradually becoming common, chiefly with the introduction of nano-technology approaches in agriculture. However, there is controversy about the effectiveness of such sparingly soluble nutrient sources as foliar fertilizers. In this work, we focussed on analysing the effect of adding Ca-carbonate (calcite, CaCO3) micro- and nano-particles as model sparingly soluble mineral compounds to foliar fertilizer formulations in terms of increasing the rate of foliar absorption. For these purposes, we carried out short-term foliar application experiments by treating leaves of species with variable surface features and wettability rates. The leaf absorption efficacy of foliar formulations containing a surfactant and model soluble nutrient sources, namely Ca-chloride (CaCl2), magnesium sulphate (MgSO4), potassium nitrate (KNO3), or zinc sulphate (ZnSO4), was evaluated alone or after addition of calcite particles. In general, the combination of the Ca-carbonate particles with an essential element salt had a synergistic effect and improved the absorption of Ca and the nutrient element provided. In light of the positive effects of using calcite particles as foliar formulation adjuvants, dolomite nano- and micro-particles were also tested as foliar formulation additives, and the results were also positive in terms of increasing foliar uptake. The observed nutrient element foliar absorption efficacy can be partially explained by geochemical modelling, which enabled us to predict how these formulations will perform at least in chemical terms. Our results show the major potential of adding mineral particles as foliar formulation additives, but the associated mechanisms of action and possible additional benefits to plants should be characterised in future investigations.
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Affiliation(s)
- Carlos Pimentel
- Université Grenoble Alpes, Université Savoie Mont Blanc, CNRS, IRD, Université Gustave Eiffel, ISTerre, 38000 Grenoble, France
| | - Carlos M. Pina
- Departamento de Mineralogía y Petrología, Facultad de Ciencias Geológicas, Universidad Complutense de Madrid, 28040 Madrid, Spain;
- Instituto de Geociencias (UCM-CSIC), 28040 Madrid, Spain
| | - Nora Müller
- New Applications Research Group, Research and Development Services, Omya International AG, 4622 Egerkingen, Switzerland; (N.M.); (G.M.R.); (F.O.); (J.S.)
| | - Luis Adrián Lara
- Systems and Natural Resources Department, School of Forest Engineering, Polytechnic University of Madrid, 28040 Madrid, Spain;
| | - Gabriela Melo Rodriguez
- New Applications Research Group, Research and Development Services, Omya International AG, 4622 Egerkingen, Switzerland; (N.M.); (G.M.R.); (F.O.); (J.S.)
| | - Fabrizio Orlando
- New Applications Research Group, Research and Development Services, Omya International AG, 4622 Egerkingen, Switzerland; (N.M.); (G.M.R.); (F.O.); (J.S.)
| | - Joachim Schoelkopf
- New Applications Research Group, Research and Development Services, Omya International AG, 4622 Egerkingen, Switzerland; (N.M.); (G.M.R.); (F.O.); (J.S.)
| | - Victoria Fernández
- Systems and Natural Resources Department, School of Forest Engineering, Polytechnic University of Madrid, 28040 Madrid, Spain;
- Centro para la Conservación de la Biodiversidad y el Desarrollo Sostenible, School of Forest Engineering, Polytechnic University of Madrid, 28040 Madrid, Spain
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Pizzo JS, Pelvine RA, da Silva ALBR, Mikcha JMG, Visentainer JV, Rodrigues C. Use of Essential Oil Emulsions to Control Escherichia coli O157:H7 in the Postharvest Washing of Lettuce. Foods 2023; 12:2571. [PMID: 37444307 DOI: 10.3390/foods12132571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/22/2023] [Accepted: 06/27/2023] [Indexed: 07/15/2023] Open
Abstract
Essential oils (EOs) have strong antibacterial properties and can be potential sanitizers to reduce pathogen load and prevent cross-contamination during postharvest washing. The objective of this study was to investigate the efficacy of emulsions containing oregano (OR; Origanum vulgare) and winter savory (WS; Satureja montana) EOs at different concentrations (0.94 and 1.88 µL/mL) and storage times (0 h, 24 h, and 7 days), in reducing Escherichia coli O157:H7 on the surface of three types of lettuce (romaine, crisphead, and butterhead). The EO emulsions were compared with one no-rinse treatment and three rinse treatments using water, 200 ppm chlorine, and 80 ppm peroxyacetic acid (PAA), respectively, in a simulated washing system. The results showed that while the EO emulsions significantly reduced E. coli O157:H7 on crisphead lettuce over time, not all treatments were effective for romaine and butterhead lettuce. The mixture of OR and WS at concentrations of 0.94 and 1.88 µL/mL was found to be the most effective in reducing E. coli O157:H7 on inoculated lettuce, resulting in reductions of 3.52 and 3.41 log CFU/g, respectively. Furthermore, the PAA and the mixture of OR and WS at 1.88 µL/mL effectively limited bacterial cross-contamination close to the detection limit for all lettuce types during all storage times. These results suggest that OR and WS EOs could serve as potential alternatives to chemical sanitizers for postharvest lettuce washing.
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Affiliation(s)
| | | | | | - Jane Martha Graton Mikcha
- Center for Agricultural Sciences, Postgraduate Program of Food Science, State University of Maringa, Maringa 87020-900, PR, Brazil
| | | | - Camila Rodrigues
- Department of Horticulture, Auburn University, Auburn, AL 36849, USA
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