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Chon JW, Jung JY, Ahn Y, Bae D, Khan S, Seo KH, Kim H, Sung K. Detection of Campylobacter jejuni from Fresh Produce: Comparison of Culture- and PCR-based Techniques, and Metagenomic Approach for Analyses of the Microbiome before and after Enrichment. J Food Prot 2021; 84:1704-1712. [PMID: 33878155 DOI: 10.4315/jfp-20-408] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 04/14/2021] [Indexed: 11/11/2022]
Abstract
ABSTRACT In this study, we compared the efficiency of culture-based methods with or without membrane filtration, real-time PCR, and digital droplet PCR (ddPCR) for the detection of Campylobacter in fresh produce. Alfalfa sprouts, clover sprouts, coleslaw, and lettuce salad spiked with Campylobacter jejuni were enriched in Bolton broth for 48 h, and enrichment cultures were either directly inoculated onto modified charcoal-cefoperazone-deoxycholate agar or applied on membrane filters placed on the surface of plating media. In parallel, 2-mL Bolton broth cultures were taken to extract DNA for real-time PCR and ddPCR assays and bacterial community analysis. A developed primer set for ddPCR and real-time PCR was evaluated for its inclusivity and exclusivity using pure culture of C. jejuni and non-C. jejuni strains, respectively. In pure culture, the primer set reacted only with C. jejuni strains and showed negative reaction to non-C. jejuni strains. There was no significant difference (P > 0.05) in the detection efficiency of positive Campylobacter isolates from coleslaw and lettuce salad using four detection methods. However, for sprout samples, the detection efficiency of the culture method was significantly (P < 0.05) lower than those of the two PCR assays and the filtration method. The analysis also revealed the presence of Pseudomonas and Acinetobacter as the most prevalent competing microbiota in enriched culture and only Acinetobacter on agar plates in the selective culture step. HIGHLIGHTS
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Affiliation(s)
- Jung-Whan Chon
- Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas 72079, USA
| | - Ji Young Jung
- Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas 72079, USA
| | - Youngbeom Ahn
- Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas 72079, USA
| | - Dongryeoul Bae
- Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas 72079, USA
| | - Saeed Khan
- Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas 72079, USA
| | - Kun-Ho Seo
- Center for One Health, College of Veterinary Medicine, Konkuk University, Hwayang-dong, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Hyunsook Kim
- Department of Food & Nutrition, College of Human Ecology, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 04763, Republic of Korea
| | - Kidon Sung
- Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas 72079, USA
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Rubin J, Mussio K, Xu Y, Suh J, Riley LW. Prevalence of Antimicrobial Resistance Genes and Integrons in Commensal Gram-Negative Bacteria in a College Community. Microb Drug Resist 2020; 26:1227-1235. [PMID: 31985343 DOI: 10.1089/mdr.2019.0279] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Although the human intestinal microbiome has been shown to harbor antimicrobial drug resistance genes (ARGs), the prevalence of such genes in a healthy population and their impact on extraintestinal infections that occur in that community are not well established. This study sought to identify ARG prevalence and their mobile elements in the intestines of a healthy community population at a California University, and compared these genes to those previously identified among uropathogenic Escherichia coli isolated from patients with urinary tract infection from the same community. We isolated Gram-negative bacteria (GNB) from fecal samples of healthy volunteers and screened them by polymerase chain reaction for class 1 integron cassette sequences and ARGs encoding resistance against ampicillin, trimethoprim-sulfamethoxazole, gentamicin, and colistin. We found antimicrobial-resistant GNB from 83 (81%) of 102 nonredundant rectal swab samples. Seventy-four (72%) of these samples contained β-lactamase genes (blaTEM, blaSHV, blaCTX-M, blaOXA, and blaOXY), dihydrofolate reductase (DHFR) genes (dhfr-A17, dhfr-A12, dhfr-A7, dhfr-A5, dhfr-A21, dhfr-A1, dhfr-A13, and dhfr-7), and aminoglycoside resistance genes (aadA5, aadA2, aadA1, and aadB). Integron sequences were found in 37 (36%) fecal samples. These genes were found in 11 different GNB species. The high prevalence of clinically common ARGs and integrons harbored by GNB in the intestine of a healthy population suggest that human intestines may serve as a major reservoir of these mobile ARGs that appear in E. coli strains causing extraintestinal infections in the same community.
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Affiliation(s)
- Julia Rubin
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, California, USA
| | - Kaitlyn Mussio
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, California, USA
| | - Yuqi Xu
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Peking University, Beijing, China
| | - Joy Suh
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, California, USA
| | - Lee W Riley
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, California, USA
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Keshri J, Krouptiski Y, Abu-Fani L, Achmon Y, Bauer TS, Zarka O, Maler I, Pinto R, Sela Saldinger S. Dynamics of bacterial communities in alfalfa and mung bean sprouts during refrigerated conditions. Food Microbiol 2019; 84:103261. [PMID: 31421775 DOI: 10.1016/j.fm.2019.103261] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 06/07/2019] [Accepted: 07/05/2019] [Indexed: 02/08/2023]
Abstract
Sprouts are considered a healthy ready-to-eat food and has gained popularity in recent years. The objective of the present study was to determine the dynamics of sprouts' microbiome during cold storage to the end of their shelf-life at home. The microbiological quality of fresh alfalfa (Medicago sativa) and mung bean (Vigna radiata) sprouts from two commercial brands was tested and the number of APC ranges from 5.0 to 8.7 log CFU/g in alfalfa and 6.7 to 9.3 log CFU/g in mung bean sprouts. In the case of alfalfa, but not mung beans, there were differences in the mean numbers of APC between the two brands. The number of coliform bacteria ranges from 4.3 to 7.7 log CFU/g in alfalfa and 4.1 to 8.1 log CFU/g in mung bean sprouts. Four independent batches of sprouts were used for DNA preparation and were sampled immediately after purchase and once a week during subsequent storage in refrigerator until the end of their shelf-life. Microbial population of the sprouts was determined using next generation sequencing of 16S rRNA amplicons. Alfalfa sprouts were dominated by Pseudomonas throughout the storage time with relative abundance of >60% at 3 weeks. Fresh mung bean sprouts were dominated by both Pseudomonas and Pantoea, but Pantoea became the dominant taxa after 2 weeks of storage, with >46% of relative abundance. The bacterial communities associated with sprouts were largely dependent on the sprout type, and less dependent on the brand. The species richness and diversity declined during storage and the development of spoilage. Among the 160 genera identified on sprouts, 23 were reported to contain known spoilage-associated species and 30 genera comprise potential human pathogenic species. This study provides new insight into the microbiome dynamics of alfalfa and mung bean sprouts during cold storage.
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Affiliation(s)
- Jitendra Keshri
- Department of Food Science, Institute for Postharvest and Food Sciences, The Volcani Center, Agriculture Research Organization, Rishon-LeZion, Israel; College of Veterinary Medicine, Western University of Health Sciences, Pomona, CA, 91766, USA
| | - Yulia Krouptiski
- Department of Food Science, Institute for Postharvest and Food Sciences, The Volcani Center, Agriculture Research Organization, Rishon-LeZion, Israel
| | - Lareen Abu-Fani
- Department of Food Science, Institute for Postharvest and Food Sciences, The Volcani Center, Agriculture Research Organization, Rishon-LeZion, Israel
| | - Ygal Achmon
- Department of Food Science, Institute for Postharvest and Food Sciences, The Volcani Center, Agriculture Research Organization, Rishon-LeZion, Israel; Department of Biotechnology and Food Engineering, Guangdong Technion Israel Institute of Technology, Shantou, China
| | - Tal Stern Bauer
- Department of Food Science, Institute for Postharvest and Food Sciences, The Volcani Center, Agriculture Research Organization, Rishon-LeZion, Israel; Department of Biochemistry and Food Science, Hebrew University of Jerusalem, Israel
| | - Omri Zarka
- Department of Food Science, Institute for Postharvest and Food Sciences, The Volcani Center, Agriculture Research Organization, Rishon-LeZion, Israel
| | - Ilana Maler
- The Laboratory of Food Microbiology, Kimron Veterinary Institute, P.O. Box 12, Bet Dagan, 50250, Israel
| | - Riky Pinto
- Department of Food Science, Institute for Postharvest and Food Sciences, The Volcani Center, Agriculture Research Organization, Rishon-LeZion, Israel
| | - Shlomo Sela Saldinger
- Department of Food Science, Institute for Postharvest and Food Sciences, The Volcani Center, Agriculture Research Organization, Rishon-LeZion, Israel.
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Chon JW, Kim DH, Bae D, Song KY, Kim H, Sung K, Seo KH. Comparison of Direct Syringe Filtration and Membrane Filtration for the Selective Isolation of Campylobacter jejuni from Ready-to-Eat Sprouts. Foodborne Pathog Dis 2019; 16:371-375. [PMID: 30864872 DOI: 10.1089/fpd.2018.2546] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Culture method using enrichment broth and selective agar is one of the most common isolation methods for detecting Campylobacter jejuni from food. However, the overgrowth of competing bacteria in enrichment culture complicates the selective isolation of C. jejuni. In this study, we compared an enrichment/plating method for the isolation of C. jejuni from sprout samples with an enrichment/plating method with syringe or membrane filtration when transferring enriched broths to plates. Four types of sprout samples were artificially contaminated with various levels of C. jejuni and incubated in 100 mL of Bolton broth for 48 h. Enrichment broths were either directly transferred onto modified charcoal-cefoperazone-deoxycholate agar or filtered through membrane or with a syringe. A significantly higher (p < 0.05) isolation rate of Campylobacter positives was obtained with both filtration methods (58-61%) than with the method without filtration (10%). Membrane filtrations yielded 61%, whereas syringe yielded 58% positives. In most cases of unfiltered samples (98%), high competing flora covered most of the plate, making differentiation and picking of suspicious colonies difficult. However, less plates were contaminated with competing flora in both filtration methods. Only 5% of plates were contaminated in the syringe filtration method, whereas no competing flora was observed in membrane filtration (0%).
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Affiliation(s)
- Jung-Whan Chon
- 1 Center for One Health, College of Veterinary Medicine, Konkuk University, Seoul, Korea
| | - Dong-Hyeon Kim
- 1 Center for One Health, College of Veterinary Medicine, Konkuk University, Seoul, Korea
| | - Dongryeoul Bae
- 2 Arkansas Regional Laboratory, Office of Regulatory, U.S. Food and Drug Administration, Jefferson, Arkansas
| | - Kwang-Young Song
- 1 Center for One Health, College of Veterinary Medicine, Konkuk University, Seoul, Korea
| | - Hyunsook Kim
- 3 Department of Food and Nutrition, College of Human Ecology, Hanyang University, Seoul, Korea
| | - Kidon Sung
- 4 Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas
| | - Kun-Ho Seo
- 1 Center for One Health, College of Veterinary Medicine, Konkuk University, Seoul, Korea
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Margot H, Stephan R, Tasara T. Mungo bean sprout microbiome and changes associated with culture based enrichment protocols used in detection of Gram-negative foodborne pathogens. MICROBIOME 2016; 4:48. [PMID: 27600392 PMCID: PMC5012049 DOI: 10.1186/s40168-016-0193-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 08/31/2016] [Indexed: 06/06/2023]
Abstract
BACKGROUND Fresh sprouted seeds have been associated with a number of large outbreaks caused by Salmonella and Shiga toxin-producing E. coli. However, the high number of commensal bacteria found on sprouted seeds hampers the detection of these pathogens. Knowledge about the composition of the sprout microbiome is limited. In this study, the microbiome of mungo bean sprouts and the impact of buffered peptone water (BPW) and Enterobacteriaceae enrichment broth (EE-broth)-based enrichment protocols on this microbiome were investigated. RESULTS Assessments based on aerobic mesophilic colony counts showed similar increases in mungo bean sprout background flora levels independent of the enrichment protocol used. 16S rRNA sequencing revealed a mungo bean sprout microbiome dominated by Proteobacteria and Bacteroidetes. EE-broth enrichment of such samples preserved and increased Proteobacteria dominance while reducing Bacteroidetes and Firmicutes relative abundances. BPW enrichment, however, increased Firmicutes relative abundance while decreasing Proteobacteria and Bacteroidetes levels. Both enrichments also lead to various genus level changes within the Protobacteria and Firmicutes phyla. CONCLUSIONS New insights into the microbiome associated with mungo bean sprout and how it is influenced through BPW and EE-broth-based enrichment strategies used for detecting Gram-negative pathogens were generated. BPW enrichment leads to Firmicutes and Proteobacteria dominance, whereas EE-broth enrichment preserves Proteobacteria dominance in the mungo bean sprout samples. By increasing the relative abundance of Firmicutes, BPW also increases the abundance of Gram-positive organisms including some that might inhibit recovery of Gram-negative pathogens. The use of EE-broth, although preserving and increasing the dominance of Proteobacteria, can also hamper the detection of lowly abundant Gram-negative target pathogens due to outgrowth of such organisms by the highly abundant non-target Proteobacteria genera comprising the mungo bean sprout associated background flora.
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Affiliation(s)
- Heike Margot
- Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich, Winterthurerstrasse 272, 8057 Zurich, Switzerland
| | - Roger Stephan
- Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich, Winterthurerstrasse 272, 8057 Zurich, Switzerland
| | - Taurai Tasara
- Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich, Winterthurerstrasse 272, 8057 Zurich, Switzerland
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6
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Effects of different media on the enrichment of low numbers of Shiga toxin-producing Escherichia coli in mung bean sprouts and on the development of the sprout microbiome. Int J Food Microbiol 2016; 232:26-34. [DOI: 10.1016/j.ijfoodmicro.2016.05.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 05/02/2016] [Accepted: 05/03/2016] [Indexed: 11/15/2022]
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7
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Asakura H, Tachibana M, Taguchi M, Hiroi T, Kurazono H, Makino SI, Kasuga F, Igimi S. Seasonal and Growth-Dependent Dynamics of Bacterial Community in Radish Sprouts. J Food Saf 2016. [DOI: 10.1111/jfs.12256] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Hiroshi Asakura
- Division of Biomedical Food Research; National Institute of Health Sciences; Kamiyoga 1-18-1 Setagaya-ku Tokyo Japan
| | - Masato Tachibana
- Division of Biomedical Food Research; National Institute of Health Sciences; Kamiyoga 1-18-1 Setagaya-ku Tokyo Japan
| | - Masumi Taguchi
- Department of Bacteriology; Osaka Prefectural Institute of Public Health; Nakamichi 1-3-69 Higashinari-ku, Osaka Osaka Japan
| | - Toyoko Hiroi
- Department of Animal and Food Hygiene; Obihiro University of Agriculture and Veterinary Medicine; Nishi 2-11 Inada-cho Obihiro Hokkaido Japan
| | - Hisao Kurazono
- Department of Animal and Food Hygiene; Obihiro University of Agriculture and Veterinary Medicine; Nishi 2-11 Inada-cho Obihiro Hokkaido Japan
| | - Sou-Ichi Makino
- Department of Domestic Science; Kyoto Seibo College; Fukakusa taya-cho, Fushimi-ku, Kyoto Kyoto Japan
| | - Fumiko Kasuga
- Division of Safety Information on Food; Drugs, and Chemicals, National Institute of Health Sciences; Kamiyoga 1-18-1 Setagaya-ku Tokyo Japan
| | - Shizunobu Igimi
- Division of Biomedical Food Research; National Institute of Health Sciences; Kamiyoga 1-18-1 Setagaya-ku Tokyo Japan
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Brehm-Stecher B, Bisha B. Flow Cytometry for Rapid Detection of Salmonella spp. in Seed Sprouts. SCIENCEOPEN RESEARCH 2014. [DOI: 10.14293/s2199-1006.1.sor-life.aj19wr.v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Seed sprouts (alfalfa, mung bean, radish, etc.) have been implicated in several recent national and international outbreaks of salmonellosis. Conditions used for sprouting are also conducive to the growth of Salmonella. As a result, this pathogen can quickly grow to very high cell densities during sprouting without any detectable organoleptic impact. Seed sprouts typically also support heavy growth (~108 CFU g-1) of a heterogeneous microbiota consisting of various bacterial, yeast and mold species, often dominated by non-pathogenic members of the family Enterobacteriaceae. This heavy background may present challenges to the detection of Salmonella, especially if this pathogen is present in relatively low numbers. We combined DNA-based fluorescence in situ hybridization (FISH) with flow cytometry (FCM) for the rapid molecular detection of Salmonella enterica Ser. Typhimurium in artificially contaminated alfalfa and other seed sprouts. Components of the assay included a set of cooperatively binding probes, a chemical blocking treatment intended to reduce non-specific background and sample concentration via tangential flow filtration (TFF). We were able to detect S. Typhimurium in sprout wash at levels as low as 103 CFU ml-1 sprout wash (104 CFU g-1 sprouts) against high microbial backgrounds (~108 CFU g-1 sprouts). Hybridization times were typically 30 min, with additional washing, but we ultimately found that S. Typhimurium could be readily detected using hybridization times as short as 2 min, without a wash step. These results clearly demonstrate the potential of combined DNA-FISH and FCM for rapid detection of Salmonella in this challenging food matrix and provides industry with a useful tool for compliance with sprout production standards proposed in the Food Safety Modernization Act (FSMA).
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Ding H, Fu TJ, Smith MA. Microbial Contamination in Sprouts: How Effective Is Seed Disinfection Treatment? J Food Sci 2013; 78:R495-501. [DOI: 10.1111/1750-3841.12064] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 12/26/2012] [Indexed: 11/30/2022]
Affiliation(s)
| | - Tong-Jen Fu
- U.S. Food and Drug Administration, Div. of Food Processing Science & Technology; Bedford Park; IL; U.S.A
| | - Michelle A. Smith
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition; College Park; MD; U.S.A
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10
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Yamazaki A, Li J, Hutchins WC, Wang L, Ma J, Ibekwe AM, Yang CH. Commensal effect of pectate lyases secreted from Dickeya dadantii on proliferation of Escherichia coli O157:H7 EDL933 on lettuce leaves. Appl Environ Microbiol 2011; 77:156-62. [PMID: 21075884 PMCID: PMC3019694 DOI: 10.1128/aem.01079-10] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Accepted: 10/31/2010] [Indexed: 11/20/2022] Open
Abstract
The outbreaks caused by enterohemorrhagic Escherichia coli O157:H7 on leafy greens have raised serious and immediate food safety concerns. It has been suggested that several phytopathogens aid in the persistence and proliferation of the human enteropathogens in the phyllosphere. In this work, we examined the influence of virulence mechanisms of Dickeya dadantii 3937, a broad-host-range phytopathogen, on the proliferation of the human pathogen E. coli O157:H7 EDL933 (EDL933) on postharvest lettuce by coinoculation of EDL933 with D. dadantii 3937 derivatives that have mutations in virulence-related genes. A type II secretion system (T2SS)-deficient mutant of D. dadantii 3937, A1919 (ΔoutC), lost the capability to promote the multiplication of EDL933, whereas Ech159 (ΔrpoS), a stress-responsive σ factor RpoS-deficient mutant, increased EDL933 proliferation on lettuce leaves. A spectrophotometric enzyme activity assay revealed that A1919 (ΔoutC) was completely deficient in the secretion of pectate lyases (Pels), which play a major role in plant tissue maceration. In contrast to A1919 (ΔoutC), Ech159 (ΔrpoS) showed more than 2-fold-greater Pel activity than the wild-type D. dadantii 3937. Increased expression of pelD (encodes an endo-pectate lyase) was observed in Ech159 (ΔrpoS) in planta. These results suggest that the pectinolytic activity of D. dadantii 3937 is the dominant determinant of enhanced EDL933 proliferation on the lettuce leaves. In addition, RpoS, the general stress response σ factor involved in cell survival in suboptimal conditions, plays a role in EDL933 proliferation by controlling the production of pectate lyases in D. dadantii 3937.
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Affiliation(s)
- Akihiro Yamazaki
- Department of Biological Sciences, University of Wisconsin—Milwaukee, Milwaukee, Wisconsin 53211, Department of Civil Engineering and Mechanics, University of Wisconsin—Milwaukee, Milwaukee, Wisconsin 53211, USDA-ARS U.S. Salinity Laboratory, Riverside, California 92507
| | - Jin Li
- Department of Biological Sciences, University of Wisconsin—Milwaukee, Milwaukee, Wisconsin 53211, Department of Civil Engineering and Mechanics, University of Wisconsin—Milwaukee, Milwaukee, Wisconsin 53211, USDA-ARS U.S. Salinity Laboratory, Riverside, California 92507
| | - William C. Hutchins
- Department of Biological Sciences, University of Wisconsin—Milwaukee, Milwaukee, Wisconsin 53211, Department of Civil Engineering and Mechanics, University of Wisconsin—Milwaukee, Milwaukee, Wisconsin 53211, USDA-ARS U.S. Salinity Laboratory, Riverside, California 92507
| | - Lixia Wang
- Department of Biological Sciences, University of Wisconsin—Milwaukee, Milwaukee, Wisconsin 53211, Department of Civil Engineering and Mechanics, University of Wisconsin—Milwaukee, Milwaukee, Wisconsin 53211, USDA-ARS U.S. Salinity Laboratory, Riverside, California 92507
| | - Jincai Ma
- Department of Biological Sciences, University of Wisconsin—Milwaukee, Milwaukee, Wisconsin 53211, Department of Civil Engineering and Mechanics, University of Wisconsin—Milwaukee, Milwaukee, Wisconsin 53211, USDA-ARS U.S. Salinity Laboratory, Riverside, California 92507
| | - A. Mark Ibekwe
- Department of Biological Sciences, University of Wisconsin—Milwaukee, Milwaukee, Wisconsin 53211, Department of Civil Engineering and Mechanics, University of Wisconsin—Milwaukee, Milwaukee, Wisconsin 53211, USDA-ARS U.S. Salinity Laboratory, Riverside, California 92507
| | - Ching-Hong Yang
- Department of Biological Sciences, University of Wisconsin—Milwaukee, Milwaukee, Wisconsin 53211, Department of Civil Engineering and Mechanics, University of Wisconsin—Milwaukee, Milwaukee, Wisconsin 53211, USDA-ARS U.S. Salinity Laboratory, Riverside, California 92507
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Buchholz A, Matthews K. Reduction of Salmonella on alfalfa seeds using peroxyacetic acid and a commercial seed washer is as effective as treatment with 20 000 ppm of Ca(OCl)2. Lett Appl Microbiol 2010; 51:462-8. [DOI: 10.1111/j.1472-765x.2010.02929.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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YE JIANXIONG, KOSTRZYNSKA MAGDALAENA, DUNFIELD KARI, WARRINER KEITH. Control of Salmonella on Sprouting Mung Bean and Alfalfa Seeds by Using a Biocontrol Preparation Based on Antagonistic Bacteria and Lytic Bacteriophages. J Food Prot 2010; 73:9-17. [DOI: 10.4315/0362-028x-73.1.9] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The following reports on the application of a combination of antagonistic bacteria and lytic bacteriophages to control the growth of Salmonella on sprouting mung beans and alfalfa seeds. Antagonistic bacteria were isolated from mung bean sprouts and tomatoes by using the deferred plate assay to assess anti-Salmonella activity. From the isolates screened, an Enterobacter asburiae strain (labeled “JX1”) exhibited stable antagonistic activity against a broad range of Salmonella serovars (Agona, Berta, Enteritidis, Hadar, Heidelberg, Javiana, Montevideo, Muenchen, Newport, Saint Paul, and Typhimurium). Lytic bacteriophages against Salmonella were isolated from pig or cattle manure effluent. A bacteriophage cocktail prepared from six isolates was coinoculated with E. asburiae JX1 along with Salmonella in broth culture. The combination of E. asburiae JX1 and bacteriophage cocktail reduced the levels of Salmonella by 5.7 to 6.4 log CFU/ml. Mung beans inoculated with Salmonella and sprouted over a 4-day period attained levels of 6.72 ± 0.78 log CFU/g. In contrast, levels of Salmonella were reduced to 3.31 ± 2.48 or 1.16 ± 2.14 log CFU/g when the pathogen was coinoculated with bacteriophages or E. asburiae JX1, respectively. However, by using a combination of E. asburiae JX1and bacteriophages, the levels of Salmonella associated with mung bean sprouts were only detected by enrichment. The biocontrol preparation was effective at controlling the growth of Salmonella under a range of sprouting temperatures (20 to 30°C) and was equally effective at suppressing the growth of Salmonella on sprouting alfalfa seeds. The combination of E. asburiae JX1 and bacteriophages represents a promising, chemical-free approach for controlling the growth of Salmonella on sprouting seeds.
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Affiliation(s)
- JIANXIONG YE
- 1Department of Food Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - MAGDALAENA KOSTRZYNSKA
- 2Food Program, Agriculture & Agri-Food Canada, 93 Stone Road West, Guelph, Ontario, Canada N1G 5C9
| | - KARI DUNFIELD
- 3Land Resource Sciences, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - KEITH WARRINER
- 1Department of Food Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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Cobo Molinos A, Abriouel H, Ben Omar N, López RL, Gálvez A. Microbial diversity changes in soybean sprouts treated with enterocin AS-48. Food Microbiol 2009; 26:922-6. [PMID: 19835782 DOI: 10.1016/j.fm.2009.06.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2009] [Revised: 06/27/2009] [Accepted: 06/29/2009] [Indexed: 11/15/2022]
Abstract
Seed sprouts may act as vehicles for foodborne pathogenic bacteria. In the present study, the effect of washing treatment with the enterococcal bacteriocin enterocin AS-48 on the microbiota of two batches of soybean sprouts was studied by culture-dependent and independent methods throughout storage at 10 degrees C. Viable cell counts of bacteriocin-treated samples revealed some modifications only for lactic acid bacteria and enterococci during storage. In the control samples from batch 1, the culture-independent DGGE analysis revealed species from genera Rahnella and Serratia as the predominant bacteria at early stages. Several bands corresponding to other genera (two Pantoea bands, one Escherichia band, and five Enterobacter bands) were also detected during storage of control samples, especially at days 3 and 5, while one Rahnella band disappeared. By contrast, some of the enterobacteria (Pantoea Escherichia and Enterobacter) were not detected or showed very faint bands in batch 1 bacteriocin-treated samples, in which two new and intense bands corresponding to genera Enterococcus and Leuconostoc were detected. Batch 2 showed a more homogeneous bacterial population, composed mainly by species of genus Enterobacter together with Pantoea. The major modifications detected in the bacteriocin-treated samples from batch 2 included the loss of one genus Enterobacter band at days 3, 5 and 7, and the detection of a new band corresponding to genus Leuconostoc at days 5 and 7. These results suggest that bacteriocin treatment disturbs the microbial balance in sprouts, producing changes in the microbial profile that cannot be detected by culture-dependent methods. The results also encourage the use of culture-independent methods to gain more insights into the global effects of bacteriocins in food systems.
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Affiliation(s)
- Antonio Cobo Molinos
- Area de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén, 23071-Jaén, Spain
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Bisha B, Brehm-Stecher BF. Flow-through imaging cytometry for characterization ofSalmonellasubpopulations in alfalfa sprouts, a complex food system. Biotechnol J 2009; 4:880-7. [DOI: 10.1002/biot.200800360] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Kim H, Lee Y, Beuchat LR, Yoon BJ, Ryu JH. Microbiological examination of vegetable seed sprouts in Korea. J Food Prot 2009; 72:856-9. [PMID: 19435238 DOI: 10.4315/0362-028x-72.4.856] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Sprouted vegetable seeds used as food have been implicated as sources of outbreaks of Salmonella and Escherichia coli O157:H7 infections. We profiled the microbiological quality of sprouts and seeds sold at retail shops in Seoul, Korea. Ninety samples of radish sprouts and mixed sprouts purchased at department stores, supermarkets, and traditional markets and 96 samples of radish, alfalfa, and turnip seeds purchased from online stores were analyzed to determine the number of total aerobic bacteria (TAB) and molds or yeasts (MY) and the incidence of Salmonella, E. coli O157:H7, and Enterobacter sakazakii. Significantly higher numbers of TAB (7.52 log CFU/g) and MY (7.36 log CFU/g) were present on mixed sprouts than on radish sprouts (6.97 and 6.50 CFU/g, respectively). Populations of TAB and MY on the sprouts were not significantly affected by location of purchase. Radish seeds contained TAB and MY populations of 4.08 and 2.42 log CFU/g, respectively, whereas populations of TAB were only 2.54 to 2.84 log CFU/g and populations of MY were 0.82 to 1.69 log CFU/g on alfalfa and turnip seeds, respectively. Salmonella and E. coli O157:H7 were not detected on any of the sprout and seed samples tested. E. sakazakii was not found on seeds, but 13.3% of the mixed sprout samples contained this potentially pathogenic bacterium.
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Affiliation(s)
- Hoikyung Kim
- Division of Human Environmental Science and Institute of Biotechnology, Wonkwang University, 344-2 Shinyong-dong, Iksan, Jeonbuk 570-749, Republic of Korea
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