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Abstract
Human noroviruses (HuNoV) are the leading cause of foodborne disease, and poor personal hygiene practices of infected workers are the most common mode of contamination. The purpose of this study was to characterize the persistence and transferability of representative noroviruses Norwalk virus (NV), Snow Mountain virus (SMV), and murine norovirus 1 (MNV-1) on and between solid surfaces and foods. Changes in virus concentration on artificially inoculated solid surfaces (stainless steel, ceramic, and Formica) or lettuce were monitored over a period of 14 to 42 days. Virus transfer was evaluated from donor (solid surface) to recipient (food, e.g., lettuce and sliced turkey deli meat) for up to 2 h postinoculation. Viruses were recovered by elution and titered with reverse transcription quantitative PCR (RT-qPCR) and/or infectivity assay, as appropriate. Based on RTqPCR, the concentration of NV and SMV on surfaces dropped gradually over time, with an average reduction of 1.5 to 2.0 and 1.8 to 2.3 log, respectively, after 42 days, with no statistically significant differences by surface. When inoculated onto lettuce stored for 2 weeks at 4°C and room temperature, the titers of NV and SMV dropped by approximately 1.0 and 1.2 to 1.8 log, respectively. Comparatively, the RT-qPCR signal associated with purified HuNoV RNA placed on the same surfaces was more rapidly lost to degradation. Transfer efficiency ranged from 0 to 26 % for lettuce and from 55 to 95 % for sliced turkey deli meat, with statistically significant differences (P ≤ 0.05) in transferability as a function of contact pressure (100 and 1,000 g/9 cm(2)) and inoculum drying time. When similar experiments were done with MNV-1, infectious virus failed to be detected on solid surfaces after storage day 21, although the virus did persist on lettuce. This study provides much needed quantitative data for use in risk assessment efforts intended to characterize the transmission of HuNoV during food preparation and handling.
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Affiliation(s)
- B I Escudero
- Department of Food Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, NC 27695, USA
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3
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Abstract
AIMS In this article, a quantitative real-time PCR assay for detection and enumeration of the spoilage yeast Dekkera anomala in beer, cola, apple cider, and brewing wort is presented as an improvement upon existing detection methods, which are very time-consuming and not always accurate. METHODS AND RESULTS Primers were designed to exclude other organisms common in these beverages, and the assay was linear over 6 log units of cell concentrations. The addition of large amounts of non-target yeast DNA did not affect the efficiency of this assay. A standard curve of known DNA was established by plotting the C(t) values obtained from the QPCR against the log of plate counts on yeast peptone dextrose medium and unknowns showed exceptional correlation when tested against this standard curve. The assay was found to detect D. anomala at levels of 10-14 CFU ml⁻¹ in either cola or beer and at levels of 9·4-25·0 CFU ml⁻¹ in apple cider. The assay was also used to follow the growth of D. anomala in brewing wort. CONCLUSIONS The results indicate that real-time PCR is an effective tool for rapid, accurate detection and quantitation of D. anomala in beer, cola and apple cider. SIGNIFICANCE AND IMPACT OF THE STUDY This method gives a faster and more efficient technique to screen beer, cola, and cider samples and reduce spoilage by D. anomala. Faster screening may allow for significant reduction in economic loss because of reduced spoilage.
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Affiliation(s)
- S R Gray
- Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, NC 27695-7624, USA
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5
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Makarova K, Slesarev A, Wolf Y, Sorokin A, Mirkin B, Koonin E, Pavlov A, Pavlova N, Karamychev V, Polouchine N, Shakhova V, Grigoriev I, Lou Y, Rohksar D, Lucas S, Huang K, Goodstein DM, Hawkins T, Plengvidhya V, Welker D, Hughes J, Goh Y, Benson A, Baldwin K, Lee JH, Díaz-Muñiz I, Dosti B, Smeianov V, Wechter W, Barabote R, Lorca G, Altermann E, Barrangou R, Ganesan B, Xie Y, Rawsthorne H, Tamir D, Parker C, Breidt F, Broadbent J, Hutkins R, O'Sullivan D, Steele J, Unlu G, Saier M, Klaenhammer T, Richardson P, Kozyavkin S, Weimer B, Mills D. Comparative genomics of the lactic acid bacteria. Proc Natl Acad Sci U S A 2006; 103:15611-6. [PMID: 17030793 PMCID: PMC1622870 DOI: 10.1073/pnas.0607117103] [Citation(s) in RCA: 944] [Impact Index Per Article: 52.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Lactic acid-producing bacteria are associated with various plant and animal niches and play a key role in the production of fermented foods and beverages. We report nine genome sequences representing the phylogenetic and functional diversity of these bacteria. The small genomes of lactic acid bacteria encode a broad repertoire of transporters for efficient carbon and nitrogen acquisition from the nutritionally rich environments they inhabit and reflect a limited range of biosynthetic capabilities that indicate both prototrophic and auxotrophic strains. Phylogenetic analyses, comparison of gene content across the group, and reconstruction of ancestral gene sets indicate a combination of extensive gene loss and key gene acquisitions via horizontal gene transfer during the coevolution of lactic acid bacteria with their habitats.
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Affiliation(s)
- K. Makarova
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894
| | - A. Slesarev
- Fidelity Systems Inc., 7961 Cessna Avenue, Gaithersburg, MD 20879
| | - Y. Wolf
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894
| | - A. Sorokin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894
| | - B. Mirkin
- School of Information Systems and Computer Science, Birkbeck College, University of London, Malet Street, London WC1E 7HX, United Kingdom
| | - E. Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894
- To whom correspondence may be addressed. E-mail:
, , , or
| | - A. Pavlov
- Fidelity Systems Inc., 7961 Cessna Avenue, Gaithersburg, MD 20879
| | - N. Pavlova
- Fidelity Systems Inc., 7961 Cessna Avenue, Gaithersburg, MD 20879
| | - V. Karamychev
- Fidelity Systems Inc., 7961 Cessna Avenue, Gaithersburg, MD 20879
| | - N. Polouchine
- Fidelity Systems Inc., 7961 Cessna Avenue, Gaithersburg, MD 20879
| | - V. Shakhova
- Fidelity Systems Inc., 7961 Cessna Avenue, Gaithersburg, MD 20879
| | - I. Grigoriev
- U.S. Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598
| | - Y. Lou
- U.S. Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598
| | - D. Rohksar
- U.S. Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598
| | - S. Lucas
- U.S. Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598
| | - K. Huang
- U.S. Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598
| | - D. M. Goodstein
- U.S. Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598
| | - T. Hawkins
- U.S. Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598
| | - V. Plengvidhya
- Department of Food Science, North Carolina State University, Raleigh, NC 27695
- North Carolina Agricultural Research Service, U.S. Department of Agriculture, Raleigh, NC 27695; Departments of
| | | | | | - Y. Goh
- Department of Food Science and Technology, University of Nebraska, Lincoln, NE 68583
| | - A. Benson
- Department of Food Science and Technology, University of Nebraska, Lincoln, NE 68583
| | - K. Baldwin
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN 55108
| | - J.-H. Lee
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN 55108
| | - I. Díaz-Muñiz
- Department of Food Science, University of Wisconsin, Madison, WI 53706
| | - B. Dosti
- Department of Food Science, University of Wisconsin, Madison, WI 53706
| | - V. Smeianov
- Department of Food Science, University of Wisconsin, Madison, WI 53706
| | - W. Wechter
- Department of Food Science, University of Wisconsin, Madison, WI 53706
| | - R. Barabote
- Department of Biology, University of California at San Diego, La Jolla, CA 92093
| | - G. Lorca
- Department of Biology, University of California at San Diego, La Jolla, CA 92093
| | - E. Altermann
- Department of Food Science, North Carolina State University, Raleigh, NC 27695
| | - R. Barrangou
- Department of Food Science, North Carolina State University, Raleigh, NC 27695
| | - B. Ganesan
- Center for Integrated BioSystems, Utah State University, Logan, UT 84322
| | - Y. Xie
- Nutrition and Food Science and
- Center for Integrated BioSystems, Utah State University, Logan, UT 84322
| | - H. Rawsthorne
- Department of Viticulture and Enology, University of California, Davis, CA 95616; and
| | | | | | - F. Breidt
- Department of Food Science, North Carolina State University, Raleigh, NC 27695
- North Carolina Agricultural Research Service, U.S. Department of Agriculture, Raleigh, NC 27695; Departments of
| | | | - R. Hutkins
- Department of Food Science and Technology, University of Nebraska, Lincoln, NE 68583
| | - D. O'Sullivan
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN 55108
| | - J. Steele
- Department of Food Science, University of Wisconsin, Madison, WI 53706
| | - G. Unlu
- Department of Food Science and Toxicology, University of Idaho, Moscow, ID 83844
| | - M. Saier
- Department of Biology, University of California at San Diego, La Jolla, CA 92093
| | - T. Klaenhammer
- Department of Food Science, North Carolina State University, Raleigh, NC 27695
- To whom correspondence may be addressed. E-mail:
, , , or
| | - P. Richardson
- U.S. Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598
| | - S. Kozyavkin
- Fidelity Systems Inc., 7961 Cessna Avenue, Gaithersburg, MD 20879
| | - B. Weimer
- Nutrition and Food Science and
- Center for Integrated BioSystems, Utah State University, Logan, UT 84322
- To whom correspondence may be addressed. E-mail:
, , , or
| | - D. Mills
- Department of Viticulture and Enology, University of California, Davis, CA 95616; and
- To whom correspondence may be addressed. E-mail:
, , , or
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