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Racine J, Nerney A, Kilgore S, Darner J, Spets M, Critzer F, Harris LJ, Reitz S, Waters T, Waite-Cusic J. Irrigation method matters: Contamination and die-off rates of Escherichia coli on dry bulb onions after overhead and drip irrigation in Washington State (2022-2023). J Food Prot 2024:100326. [PMID: 38977079 DOI: 10.1016/j.jfp.2024.100326] [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: 03/12/2024] [Revised: 06/30/2024] [Accepted: 07/03/2024] [Indexed: 07/10/2024]
Abstract
Two U.S. outbreaks of salmonellosis in 2020 and 2021 were epidemiologically linked to red onions. The 2020 outbreak investigation implicated production agricultural water as a likely contamination source. Field trials were designed to investigate prevalence and survival of Escherichia coli (surrogate for Salmonella) on dry bulb onions after application of contaminated irrigation water at the end of the growing period. Irrigation water was inoculated at 3 log most probable number (MPN)/100 mL (2022 and 2023) or 5 log MPN/100 mL (2023, drip only) with a cocktail of rifampin-resistant E. coli and applied with the final irrigation (0.4 acre-inch/0.4 hectare-cm) to onions. Onion bulbs (40 or 80) were sampled immediately after irrigation and throughout field curing (4 weeks) and E. coli was enumerated using a MPN method. For drip irrigation, at 3 log MPN/100 mL E. coli was detected on 13% of onions at 24 h but not detected at 0 h; at 5 log MPN/100 mL for drip irrigation applied to saturated soil, E. coli was detected in 63% of onions at 0 h. Prevalence significantly (P<0.05), decreased after 7 d of curing with cell densities of 1-1,400 MPN/onion. At the end of field curing in 2023, 1/80 onions had detectable E. coli (2.04 MPN/onion). E. coli was detected in a significantly smaller percentage of onions (2022: 13%; 2023: 68%) after a contaminated drip irrigation event compared to overhead irrigation (98-100%; P<0.05). After overhead irrigation E. coli was detected in onions (1-1,000 MPN/onion) on day 0. Prevalence decreased significantly (P <0.05) after 7 d of field curing in both years (2022: 15%; 2023: 7%). E. coli was not detected on Calibra onions (80/year) at the end of field curing in either year but was detected at <12 MPN/onion in 2.5-3.75% of onions (n=80) for other cultivars. These data confirm limited contamination risk associated with drip irrigation water quality and begin to quantify contamination risks associated with overhead irrigation of dry bulb onions.
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Affiliation(s)
- Jason Racine
- Department of Food Science and Technology, Oregon State University, Corvallis, OR, USA 97331
| | - Alexandra Nerney
- Department of Food Science and Technology, Oregon State University, Corvallis, OR, USA 97331
| | - Samantha Kilgore
- Department of Food Science and Technology, Oregon State University, Corvallis, OR, USA 97331
| | - Jennifer Darner
- Franklin County Extension, College of Agricultural, Human, and Natural Resource Sciences, Washington State University, Pasco, WA, USA 99301
| | - Madeline Spets
- Franklin County Extension, College of Agricultural, Human, and Natural Resource Sciences, Washington State University, Pasco, WA, USA 99301
| | - Faith Critzer
- Department of Food Science and Technology, University of Georgia, Athens, GA, USA 30609
| | - Linda J Harris
- Department of Food Science and Technology, University of California, Davis, Davis, CA, USA 95618
| | - Stuart Reitz
- Malheur County Experiment Station, College of Agricultural Sciences, Oregon State University, Ontario, OR, USA 97914
| | - Tim Waters
- Franklin County Extension, College of Agricultural, Human, and Natural Resource Sciences, Washington State University, Pasco, WA, USA 99301
| | - Joy Waite-Cusic
- Department of Food Science and Technology, Oregon State University, Corvallis, OR, USA 97331.
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Murphy CM, Hamilton AM, Waterman K, Rock C, Schaffner DW, Strawn LK. Efficacy of Peracetic Acid and Chlorine on the Reduction of Shiga Toxin-producing Escherichia coli and a Nonpathogenic E. coli Strain in Preharvest Agricultural Water. J Food Prot 2023; 86:100172. [PMID: 37783289 DOI: 10.1016/j.jfp.2023.100172] [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: 07/29/2023] [Revised: 09/24/2023] [Accepted: 09/27/2023] [Indexed: 10/04/2023]
Abstract
Produce-borne outbreaks of Shiga toxin-producing Escherichia coli (STEC) linked to preharvest water emphasize the need for efficacious water treatment options. This study quantified reductions of STEC and generic E. coli in preharvest agricultural water using commercially available sanitizers. Water was collected from two sources in Virginia (pond, river) and inoculated with either a seven-strain STEC panel or environmental generic E. coli strain TVS 353 (∼9 log10 CFU/100 mL). Triplicate inoculated water samples were equilibrated to 12 or 32°C and treated with peracetic acid (PAA) or chlorine (Cl) [low (PAA:6ppm, Cl:2-4 ppm) or high (PAA:10 ppm, Cl:10-12 ppm) residual concentrations] for an allotted contact time (1, 5, or 10 min). Strains were enumerated, and a log-linear model was used to characterize how treatment combinations influenced reductions. All Cl treatment combinations achieved a ≥3 log10 CFU/100 mL reduction, regardless of strain (3.43 ± 0.25 to 7.05 ± 0.00 log10 CFU/100 mL). Approximately 80% (19/24) and 67% (16/24) of PAA treatment combinations achieved a ≥3 log10 CFU/100 mL for STEC and E. coli TVS 353, respectively. The log-linear model showed contact time (10 > 5 > 1 min) and sanitizer type (Cl > PAA) had the greatest impact on STEC and E. coli TVS 353 reductions (p < 0.001). E. coli TVS 353 in water samples was more resistant to sanitizer treatment (p < 0.001) indicating applicability as a good surrogate. Results demonstrated Cl and PAA can be effective agricultural water treatment strategies when sanitizer chemistry is managed. These data will assist with the development of in-field validation studies and may identify suitable candidates for the registration of antimicrobial pesticide products for use against foodborne pathogens in preharvest agricultural water treatment.
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Affiliation(s)
- Claire M Murphy
- Department of Food Science and Technology, Virginia Tech, Blacksburg, VA, USA; School of Food Science, Washington State University - Irrigated Agriculture Research and Extension Center, Prosser, WA, USA
| | - Alexis M Hamilton
- Department of Food Science and Technology, Virginia Tech, Blacksburg, VA, USA
| | - Kim Waterman
- Department of Food Science and Technology, Virginia Tech, Blacksburg, VA, USA
| | - Channah Rock
- Department of Environmental Science, University of Arizona - Maricopa Agricultural Center, Maricopa, AZ, USA
| | - Donald W Schaffner
- Department of Food Science, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA
| | - Laura K Strawn
- Department of Food Science and Technology, Virginia Tech, Blacksburg, VA, USA.
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Moyne AL, Waite-Cusic J, Harris LJ. Water Application Method Influences Survival or Growth of Escherichia coli on Bulb Onions during Field Curing. J Food Prot 2022; 85:961-972. [PMID: 35333326 DOI: 10.4315/jfp-21-394] [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: 10/20/2021] [Accepted: 03/19/2022] [Indexed: 11/11/2022]
Abstract
ABSTRACT The impact of water application method on bacterial survival at or after the final irrigation was evaluated in bulb onions during commercially relevant field drying (curing). A three-strain rifampin-resistant cocktail of Escherichia coli was introduced to onions via a single overhead spray application in two separate trials (5.22 [trial 1] or 2.40 [trial 2] log CFU per onion) 2 to 3 days after the final irrigation. Onions were lifted from the soil 8 days after spray inoculation and, in some cases, foliage was removed (topping); onions remained in the field for an additional ca. 2 weeks (total ca. 3 weeks of curing). E. coli populations declined on the onions in the first 4 h after spray inoculation. E. coli was recovered from 38 (48%) or 28 (35%) of 80 whole-onion enrichments at the end of curing in trials 1 or 2, respectively. Topping did not significantly impact the percentage of E. coli-positive onions detected at the end of curing. From 8 h to 21 days, E. coli populations on positive onions ranged from 1 CFU per onion to 7 log CFU per onion in both trials, representing a potential risk of E. coli growth with overhead application of contaminated water at the end of onion production. In trial 2, additional rows of onions were inoculated via a 22-cm subsurface or surface drip irrigation line (1.94 log CFU/mL for 2.5 h). E. coli was detected in 0 (subsurface) and 4 (surface) of 50 whole-onion enrichments 3 h after the initiation of drip irrigation. Positive onions were detected at days 1 (4 of 50) and 7 (1 of 50) with subsurface drip inoculation, and at days 1 (7 of 50), 7 (2 of 50), and 14 (2 of 50) with surface drip inoculation. E. coli was not detected in whole-onion enrichments at the end of curing when inoculated by subsurface (0 of 50) or surface (0 of 50) drip irrigation. Application of contaminated water through drip irrigation, when coupled with field curing, results in low rates of contamination of bulb onions at the time of harvest. HIGHLIGHTS
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Affiliation(s)
- Anne-Laure Moyne
- Department of Food Science and Technology, University of California, Davis, One Shields Avenue, Davis, California 95616-5270.,Western Center for Food Safety, University of California, Davis, One Shields Avenue, Davis, California 95618
| | - Joy Waite-Cusic
- Department of Food Science and Technology, Oregon State University, Corvallis, Oregon, USA
| | - Linda J Harris
- Department of Food Science and Technology, University of California, Davis, One Shields Avenue, Davis, California 95616-5270.,Western Center for Food Safety, University of California, Davis, One Shields Avenue, Davis, California 95618
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Lieberman VM, Morgan EW, Harris LJ. Reduction of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella on Whole Yellow Onions (Allium cepa) Exposed to Hot Water. J Food Prot 2021; 84:1965-1972. [PMID: 34265051 DOI: 10.4315/jfp-21-242] [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: 06/09/2021] [Accepted: 07/13/2021] [Indexed: 11/11/2022]
Abstract
ABSTRACT In-home or food service antimicrobial treatment options for fresh produce are limited. Hot water treatments for whole (unpeeled) produce have been proposed, but data to support this practice for onions are not available. Separate cocktails of rifampin-resistant Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella were cultured on agar and suspended in sterile water. The outer papery skin at the equator or root or stem ends of the whole yellow onions was spot inoculated at 6 log CFU per onion. After drying for 30 min and, in some cases, storage at 4°C for 6 days, onions were immersed in water at ca. 100°C for 5 s or 85°C for 10 to 180 s. No significant difference (P > 0.05) in the mean decline of Salmonella was found on onions that were exposed to hot water after drying the inoculum for 30 min or after storage at 4°C for 6 days. Exposure of whole onions at 100°C for 5 s reduced E. coli O157:H7 and L. monocytogenes populations by >5 log CFU per onion at all inoculum sites and Salmonella populations by >5 log CFU per onion at the stem end and equator but not consistently at the root end. Mean root-end reductions of ≥5 log CFU per onion of E. coli O157:H7, L. monocytogenes, and Salmonella were achieved consistently when the root end was fully immersed in 85°C hot water for 45 or 60 s except in a small number of cases (4 of 57; 7%) when the root end was oriented upward and above the water line during treatment. When onions were held at 85°C for 180 s with the root end above the water line in an uncovered water bath, no significant declines in Salmonella populations were observed; significant mean declines in Salmonella were achieved (mean, 5 log CFU per onion; range, 3.49 to 6.25 log CFU per onion) when the water bath was covered. Short exposure to hot water can significantly reduce pathogens on the surface of whole onions. Reductions are more consistent when the root end is submerged and when the water bath is covered. HIGHLIGHTS
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Affiliation(s)
- Vanessa M Lieberman
- Department of Food Science and Technology and Western Center for Food Safety, University of California-Davis, One Shields Avenue, Davis, California 95616-8598, USA
| | - Ethan W Morgan
- Department of Food Science and Technology and Western Center for Food Safety, University of California-Davis, One Shields Avenue, Davis, California 95616-8598, USA
| | - Linda J Harris
- Department of Food Science and Technology and Western Center for Food Safety, University of California-Davis, One Shields Avenue, Davis, California 95616-8598, USA
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Zhao XX, Lin FJ, Li H, Li HB, Wu DT, Geng F, Ma W, Wang Y, Miao BH, Gan RY. Recent Advances in Bioactive Compounds, Health Functions, and Safety Concerns of Onion ( Allium cepa L.). Front Nutr 2021; 8:669805. [PMID: 34368207 PMCID: PMC8339303 DOI: 10.3389/fnut.2021.669805] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 06/28/2021] [Indexed: 12/19/2022] Open
Abstract
Onion (Allium cepa L.) is a common vegetable, widely consumed all over the world. Onion contains diverse phytochemicals, including organosulfur compounds, phenolic compounds, polysaccharides, and saponins. The phenolic and sulfur-containing compounds, including onionin A, cysteine sulfoxides, quercetin, and quercetin glucosides, are the major bioactive constituents of onion. Accumulated studies have revealed that onion and its bioactive compounds possess various health functions, such as antioxidant, antimicrobial, anti-inflammatory, anti-obesity, anti-diabetic, anticancer, cardiovascular protective, neuroprotective, hepatorenal protective, respiratory protective, digestive system protective, reproductive protective, and immunomodulatory properties. Herein, the main bioactive compounds in onion are summarized, followed by intensively discussing its major health functions as well as relevant molecular mechanisms. Moreover, the potential safety concerns about onion contamination and the ways to mitigate these issues are also discussed. We hope that this paper can attract broader attention to onion and its bioactive compounds, which are promising ingredients in the development of functional foods and nutraceuticals for preventing and managing certain chronic diseases.
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Affiliation(s)
- Xin-Xin Zhao
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, China
- Chengdu National Agricultural Science and Technology Center, Chengdu, China
| | - Fang-Jun Lin
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, United States
| | - Hang Li
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, China
| | - Hua-Bin Li
- Guangdong Provincial Key Laboratory of Food, Nutrition, and Health, Department of Nutrition, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Ding-Tao Wu
- Key Laboratory of Coarse Cereal Processing (Ministry of Agriculture and Rural Affairs), Sichuan Engineering and Technology Research Center of Coarse Cereal Industralization, Chengdu University, Chengdu, China
| | - Fang Geng
- Key Laboratory of Coarse Cereal Processing (Ministry of Agriculture and Rural Affairs), Sichuan Engineering and Technology Research Center of Coarse Cereal Industralization, Chengdu University, Chengdu, China
| | - Wei Ma
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, China
- Chengdu National Agricultural Science and Technology Center, Chengdu, China
| | - Yu Wang
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, China
- Chengdu National Agricultural Science and Technology Center, Chengdu, China
| | - Bao-He Miao
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, China
- Chengdu National Agricultural Science and Technology Center, Chengdu, China
| | - Ren-You Gan
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, China
- Chengdu National Agricultural Science and Technology Center, Chengdu, China
- Key Laboratory of Coarse Cereal Processing (Ministry of Agriculture and Rural Affairs), Sichuan Engineering and Technology Research Center of Coarse Cereal Industralization, Chengdu University, Chengdu, China
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Harrand AS, Kovac J, Carroll LM, Guariglia-Oropeza V, Kent DJ, Wiedmann M. Assembly and Characterization of a Pathogen Strain Collection for Produce Safety Applications: Pre-growth Conditions Have a Larger Effect on Peroxyacetic Acid Tolerance Than Strain Diversity. Front Microbiol 2019; 10:1223. [PMID: 31231329 PMCID: PMC6558390 DOI: 10.3389/fmicb.2019.01223] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Accepted: 05/16/2019] [Indexed: 12/21/2022] Open
Abstract
Effective control of foodborne pathogens on produce requires science-based validation of interventions and control strategies, which typically involves challenge studies with a set of bacterial strains representing the target pathogens or appropriate surrogates. In order to facilitate these types of studies, a produce-relevant strain collection was assembled to represent strains from produce outbreaks or pre-harvest environments, including Listeria monocytogenes (n = 11), Salmonella enterica (n = 23), shiga-toxin producing Escherichia coli (STEC) (n = 13), and possible surrogate organisms (n = 8); all strains were characterized by whole genome sequencing (WGS). Strain diversity was assured by including the 10 most common S. enterica serotypes, L. monocytogenes lineages I-IV, and E. coli O157 as well as selected "non-O157" STEC serotypes. As it has previously been shown that strains and genetic lineages of a pathogen may differ in their ability to survive different stress conditions, a subset of representative strains for each "pathogen group" (e.g., Salmonella, STEC) was selected and assessed for survival of exposure to peroxyacetic acid (PAA) using strains pre-grown under different conditions including (i) low pH, (ii) high salt, (iii) reduced water activity, (iv) different growth phases, (v) minimal medium, and (vi) different temperatures (21°C, 37°C). The results showed that across the three pathogen groups pre-growth conditions had a larger effect on bacterial reduction after PAA exposure as compared to strain diversity. Interestingly, bacteria exposed to salt stress (4.5% NaCl) consistently showed the least reduction after exposure to PAA; however, for STEC, strains pre-grown at 21°C were as tolerant to PAA exposure as strains pre-grown under salt stress. Overall, our data suggests that challenge studies conducted with multi-strain cocktails (pre-grown under a single specific condition) may not necessarily reflect the relevant phenotypic range needed to appropriately assess different intervention strategies.
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Affiliation(s)
| | - Jasna Kovac
- Department of Food Science, Pennsylvania State University, University Park, PA, United States
| | - Laura M. Carroll
- Department of Food Science, Cornell University, Ithaca, NY, United States
| | | | - David J. Kent
- Department of Statistical Science, Cornell University, Ithaca, NY, United States
| | - Martin Wiedmann
- Department of Food Science, Cornell University, Ithaca, NY, United States
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Wall GL, Clements DP, Fisk CL, Stoeckel DM, Woods KL, Bihn EA. Meeting Report: Key Outcomes from a Collaborative Summit on Agricultural Water Standards for Fresh Produce. Compr Rev Food Sci Food Saf 2019; 18:723-737. [PMID: 33336930 DOI: 10.1111/1541-4337.12434] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 01/21/2019] [Accepted: 01/23/2019] [Indexed: 12/01/2022]
Abstract
On February 27 to 28, 2018, the Produce Safety Alliance convened a national water summit in Covington, KY to discuss the requirements of the United States Food and Drug Administration's (FDA) Food Safety Modernization Act Standards for the Growing, Harvesting, Packing, and Holding of Produce for Human Consumption (Produce Safety Rule [PSR]). The goals of the meeting were to better understand the challenges growers face in implementing the requirements in Subpart E-Agricultural Water and work collaboratively to develop practical solutions to meet fruit and vegetable production needs while protecting public health. To meet these goals, the summit engaged a diverse group of stakeholders including growers, researchers, extension educators, produce industry members, and regulatory personnel. Key outcomes included defining implementation barriers due to diversity in water sources, distribution systems, commodity types, climates, farm size, and production activities. There was an articulated need for science-based solutions, such as the use of agricultural water system assessments and sharing of federal, state, and regional water quality data, to ensure qualitative and quantitative standards reduce microbial risks. These identified challenges and needs resulted in significant debate about whether reopening the PSR-Subpart E for modification or attempting to address concerns through guidance would provide the best mechanism for alleviating concerns. In addition, training, outreach, and technical assistance were identified as vital priorities once the concerns are formally addressed by FDA. The water summit highlighted the critical need for transparency of FDA's progress on reevaluating the Subpart E requirements to help guide growers' decisions regarding the use of agricultural water.
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Affiliation(s)
- Gretchen L Wall
- Produce Safety Alliance, Dept. of Food Science, Cornell Univ., 665 W. North Street, Geneva, NY, 14456, U.S.A
| | - Donna P Clements
- Produce Safety Alliance, Dept. of Food Science, Cornell Univ., 665 W. North Street, Geneva, NY, 14456, U.S.A
| | - Connie L Fisk
- Produce Safety Alliance, Dept. of Food Science, Cornell Univ., 665 W. North Street, Geneva, NY, 14456, U.S.A
| | - Donald M Stoeckel
- Produce Safety Alliance, Dept. of Food Science, Cornell Univ., 665 W. North Street, Geneva, NY, 14456, U.S.A
| | - Kristin L Woods
- Alabama Cooperative Extension System, Auburn University, P.O. Box 40, Grove Hill, AL, 36451, U.S.A
| | - Elizabeth A Bihn
- Produce Safety Alliance, Dept. of Food Science, Cornell Univ., 665 W. North Street, Geneva, NY, 14456, U.S.A
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