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Borkar SB, Negi M, Jaiswal A, Raj Acharya T, Kaushik N, Choi EH, Kaushik NK. Plasma-generated nitric oxide water: A promising strategy to combat bacterial dormancy (VBNC state) in environmental contaminant Micrococcus luteus. JOURNAL OF HAZARDOUS MATERIALS 2024; 461:132634. [PMID: 37793251 DOI: 10.1016/j.jhazmat.2023.132634] [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: 06/06/2023] [Revised: 09/08/2023] [Accepted: 09/24/2023] [Indexed: 10/06/2023]
Abstract
The viable but non-culturable (VBNC) is an inactive state, and certain bacteria can enter under adverse conditions. The VBNC state challenges the environment, food safety, and public health since VBNCs may resuscitate and pose a risk to human health. The aim of this study was to investigate the effect of plasma-generated nitric oxide water (PG-NOW) on airborne contaminant Micrococcus luteus (M. luteus) and examine its potential to induce the VBNC state. The essential conditions for bacteria to enter VBNC state are low metabolic activity and rare or no culturable counts. The results indicated that PG-NOW effectively eliminates M. luteus, and the remaining bacteria are in culturable condition. Moreover, the conventional cultured-based method combined with a propidium iodide monoazide quantitative PCR (PMAxxTM-qPCR) showed no significant VBNC induction and moderate culturable counts. Results from the qPCR revealed that gene levels in PG-NOW treated bacteria related to resuscitation-promoting factors, amino acid biosynthesis, and fatty acid metabolism were notably upregulated. PG-NOW inactivated M. luteus showed negligible VBNC formation and alleviated infection ability in lung cells. This study provides new insights into the potential use of PG-NOW reactive species for the prevention and control of the VBNC state of M. luteus.
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Affiliation(s)
- Shweta B Borkar
- Department of Electrical and Biological Physics/Plasma Bioscience Research Center, Kwangwoon University, Seoul 01897, South Korea
| | - Manorma Negi
- Department of Electrical and Biological Physics/Plasma Bioscience Research Center, Kwangwoon University, Seoul 01897, South Korea
| | - Apurva Jaiswal
- Department of Electrical and Biological Physics/Plasma Bioscience Research Center, Kwangwoon University, Seoul 01897, South Korea
| | - Tirtha Raj Acharya
- Department of Electrical and Biological Physics/Plasma Bioscience Research Center, Kwangwoon University, Seoul 01897, South Korea
| | - Neha Kaushik
- Department of Biotechnology, College of Engineering, The University of Suwon, Hwaseong 18323, South Korea.
| | - Eun Ha Choi
- Department of Electrical and Biological Physics/Plasma Bioscience Research Center, Kwangwoon University, Seoul 01897, South Korea.
| | - Nagendra Kumar Kaushik
- Department of Electrical and Biological Physics/Plasma Bioscience Research Center, Kwangwoon University, Seoul 01897, South Korea.
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Pseudomonas fluorescens Cells’ Recovery after Exposure to BAC and DBNPA Biocides. Antibiotics (Basel) 2022; 11:antibiotics11081042. [PMID: 36009911 PMCID: PMC9405490 DOI: 10.3390/antibiotics11081042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 07/28/2022] [Accepted: 08/01/2022] [Indexed: 02/01/2023] Open
Abstract
A proper assessment of the effects of biocides on bacterial cells is key to the prevention of antimicrobial resistance and the implementation of suitable biocidal programmes. It is particularly relevant regarding the ability of dead-labelled cells to recover their functional processes once the biocide is removed. In the present work, we studied how Pseudomonas fluorescens cells previously exposed to different concentrations of BAC (benzalkonium chloride) and DBNPA (2,2-Dibromo-3-nitrilopropionamide) behave upon the restoration of optimum growth conditions. The following indicators were evaluated: culturability, membrane integrity, metabolic activity (resazurin), cellular energy (ATP), and cell structure and morphology (transmission electron microscopy (TEM)). The results demonstrated that cells previously labelled as ‘dead’ recovered to a greater extent in all indicators. Only cells previously exposed to BAC at 160 mg/L (concentration above the MBC) showed significant reductions on all the evaluated indicators. However, the obtained values were much higher than the ‘death’ thresholds found for the autoclaved cells. This suggests that cells exposed to this concentration take more time to rebuild their functional processes. The recovery of DBNPA-treated cells did not seem to be related to the biocide concentration. Finally, a reflection on what kind of cells were able to recover (remaining cells below the detection limit and/or dormant cells) is also presented.
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Gao R, Liao X, Zhao X, Liu D, Ding T. The diagnostic tools for viable but nonculturable pathogens in the food industry: Current status and future prospects. Compr Rev Food Sci Food Saf 2021; 20:2146-2175. [PMID: 33484068 DOI: 10.1111/1541-4337.12695] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 12/21/2020] [Accepted: 12/28/2020] [Indexed: 12/21/2022]
Abstract
Viable but nonculturable (VBNC) microorganisms have been recognized as pathogenic contaminants in foods and environments. The failure of VBNC cells to form the visible colonies hinders the ability to use conventional media for their detection. Efficient and rapid detection of pathogens in the VBNC state is a prerequisite to ensure the food safety and public health. Despite their nonculturability, VBNC cells have distinct characteristics, such as morphology, metabolism, chemical composition, and gene and protein expression, that have been used as the basis for the development of abundant diagnostic tools. This review covers the current status and advances in various approaches for examining microorganisms in the VBNC state, including but not limited to the methodological aspects, advantages, and drawbacks of each technique. Existing methods, such as direct viable count, SYTO/PI dual staining, and propidium monoazide quantitative polymerase chain reaction (PCR), as well as some techniques with potential to be applied in the future, such as digital PCR, enhanced-surface Raman spectroscopy, and impedance-based techniques, are summarized in depth. Finally, future prospects for the one-step detection of VBNC bacteria are proposed and discussed. We believe that this review can provide more optional methods for researchers and promote the development of rapid, accurate detecting methods, and for inspectors, the diagnostic tools can provide data to undertake risk analysis of VBNC cells.
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Affiliation(s)
- Rui Gao
- Key Laboratory for Agro-Products Postharvest Handling of Ministry of Agriculture, Zhejiang Key Laboratory for Agro-Food Processing, Department of Food Science and Nutrition, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xinyu Liao
- Key Laboratory for Agro-Products Postharvest Handling of Ministry of Agriculture, Zhejiang Key Laboratory for Agro-Food Processing, Department of Food Science and Nutrition, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xihong Zhao
- Research Center for Environmental Ecology and Engineering, Key Laboratory for Green Chemical Process of Ministry of Education, Hubei Key Laboratory of Novel Reactor and Green Chemical Technology, School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan, China
| | - Donghong Liu
- Key Laboratory for Agro-Products Postharvest Handling of Ministry of Agriculture, Zhejiang Key Laboratory for Agro-Food Processing, Department of Food Science and Nutrition, Zhejiang University, Hangzhou, Zhejiang, China
| | - Tian Ding
- Key Laboratory for Agro-Products Postharvest Handling of Ministry of Agriculture, Zhejiang Key Laboratory for Agro-Food Processing, Department of Food Science and Nutrition, Zhejiang University, Hangzhou, Zhejiang, China
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Selvam D, Thangarasu A, Shyu DJH, Neelamegam R, Muthukalingan K, Nagarajan K. Antimicrobial Substance Produced by Pseudomonas aeruginosa Isolated from Slaughterhouse Sediment: Physicochemical Characterization, Purification, and Identification. Int J Pept Res Ther 2020. [DOI: 10.1007/s10989-020-10135-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Conte-Junior CA, Monteiro MLG, Patrícia R, Mársico ET, Lopes MM, Alvares TS, Mano SB. The Effect of Different Packaging Systems on the Shelf Life of Refrigerated Ground Beef. Foods 2020; 9:E495. [PMID: 32295229 PMCID: PMC7230568 DOI: 10.3390/foods9040495] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/06/2020] [Accepted: 04/08/2020] [Indexed: 11/24/2022] Open
Abstract
Abstract: The aim of this study was to investigate the effects of different packaging systems on the shelf life of refrigerated ground beef. The ground beef samples were packaged as follows: AA (100% ambient air), 90O2:10CO2 (90% O2 and 10% CO2), 80O2:20CO2 (80% O2 and 20% CO2), 70O2:30CO2 (70% O2 and 30% CO2), 60O2:40CO2 (60% O2 and 40% CO2), 50O2:50CO2 (50% O2 and 50% CO2), 100O2 (100% O2), and VP (vacuum packaging). All treatments were analyzed daily for O2 and CO2 levels, pH, filtration time, total volatile basic nitrogen (TVB-N), aerobic mesophilic heterotrophic bacteria (AMHB), and aerobic psychrotrophic heterotrophic bacteria (APHB) over 20 days at 2 °C. All MAP systems had a decrease of O2 and an increase of CO2 levels during storage period (p < 0.05). Overall, the MAP systems were similarly able to decrease the pH and retard the increase of TVB-N and filtration time over the storage period (p > 0.05). Moreover, the MAP systems increased the lag phase and/or the generation time of both AMHB and APHB, extending the shelf life by 3 (90O2:10CO2), 4 (70O2:30CO2 and 100O2), and 5 days (80O2:20CO2, 60O2:40CO2, 50O2:50CO2, and VP). All MAP systems were equally effective in retarding physicochemical degradation; however, 80O2:20CO2, 60O2:40CO2, 50O2:50CO2, and VP were the most effective in impairing bacterial growth and extending the shelf life of ground beef stored under refrigeration.
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Affiliation(s)
- Carlos A. Conte-Junior
- Instituto de Química, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro 21941-909, Brazil;
- Núcleo de Análise de Alimentos (NAL-LADETEC), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro 21941-598, Brazil
- Departamento de Tecnologia de Alimentos, Universidade Federal Fluminense (UFF), Niterói, Rio de Janeiro 24220-000, Brazil; (R.P.); (E.T.M.); (M.M.L.); (S.B.M.)
- Instituto Nacional de Controle de Qualidade em Saúde, Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro 21040-900, Brazil
| | - Maria Lúcia G. Monteiro
- Instituto de Química, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro 21941-909, Brazil;
- Núcleo de Análise de Alimentos (NAL-LADETEC), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro 21941-598, Brazil
- Departamento de Tecnologia de Alimentos, Universidade Federal Fluminense (UFF), Niterói, Rio de Janeiro 24220-000, Brazil; (R.P.); (E.T.M.); (M.M.L.); (S.B.M.)
| | - Renata Patrícia
- Departamento de Tecnologia de Alimentos, Universidade Federal Fluminense (UFF), Niterói, Rio de Janeiro 24220-000, Brazil; (R.P.); (E.T.M.); (M.M.L.); (S.B.M.)
| | - Eliane T. Mársico
- Departamento de Tecnologia de Alimentos, Universidade Federal Fluminense (UFF), Niterói, Rio de Janeiro 24220-000, Brazil; (R.P.); (E.T.M.); (M.M.L.); (S.B.M.)
| | - Márcia M. Lopes
- Departamento de Tecnologia de Alimentos, Universidade Federal Fluminense (UFF), Niterói, Rio de Janeiro 24220-000, Brazil; (R.P.); (E.T.M.); (M.M.L.); (S.B.M.)
| | - Thiago S. Alvares
- Instituto de Nutrição, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro 27979-000, Brazil;
| | - Sérgio B. Mano
- Departamento de Tecnologia de Alimentos, Universidade Federal Fluminense (UFF), Niterói, Rio de Janeiro 24220-000, Brazil; (R.P.); (E.T.M.); (M.M.L.); (S.B.M.)
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Combined effect of oxygen-scavenger packaging and UV-C radiation on shelf life of refrigerated tilapia (Oreochromis niloticus) fillets. Sci Rep 2020; 10:4243. [PMID: 32144402 PMCID: PMC7060221 DOI: 10.1038/s41598-020-61293-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 02/19/2020] [Indexed: 11/15/2022] Open
Abstract
This study investigated the physicochemical, instrumental and bacterial parameters of tilapia fillets subjected to oxygen-scavenger packaging, alone or in combination with UV-C radiation at two doses (0.102 and 0.301 J/cm2), stored at 4 ± 1 °C for 23 days. The oxygen scavenger, both UV-C doses, and the oxygen scavenger combined with UV-C, independently of the dose, extended the shelf life in 5, 6 and 7 days, respectively, by decreasing the bacterial growth rate and the formation of degradation compounds (e.g., TVB-N and ammonia). Oxygen-scavenger packaging, alone or in combination with UV-C at 0.102 J/cm2 and 0.301 J/cm2 showed lower amounts of free amino acids (FAA; 34.39, 34.49 and 34.50 mg L-lysine/kg fish tissue, 3.63, 3.57 and 3.61 mg L- ornithine/kg fish tissue, 27.52, 27.63 and 27.67 mg L-arginine/kg fish tissue), biogenic amines (BA; 3.81, 3.87 and 3.89 mg cadaverine/kg fish tissue, 12.88, 12.91 and 12.86 mg putrescine/kg fish tissue, 2.41, 2.44 and 2.47 mg spermidine/kg fish tissue), redness (2.53, 2.55 and 2.59), yellowness (6.65, 6.69 and 6.72), lipid oxidation (1.52, 1.53 and 1.58 mg malondialdehyde/kg fish tissue) and protein oxidation (5.06, 5.11 and 5.18 nmol carbonyls/mg protein), with higher hardness (3273.41, 2652.98 and 2687.57 g) than control (air packaging; 41.97 mg L-lysine/kg fish tissue, 4.83 mg L- ornithine/kg fish tissue, 37.33 mg L-arginine/kg fish tissue, 4.82 mg cadaverine/kg fish tissue, 16.56 mg putrescine/kg fish tissue, 3.21 mg spermidine/kg fish tissue, 4.26 of redness, 8.17 of yellowness, 2.88 mg malondialdehyde/kg fish tissue, 9.44 nmol carbonyls/mg protein and 2092.58 g of hardness), respectively, on day 13 of storage when the control fillets were unfit for consumption (7 log CFU/g) (p < 0.05). However, in the same day of storage, both UV-C doses had similar values for BA (p > 0.05), higher amounts of FAA (44.28 and 44.13 mg L-lysine/kg fish tissue, 5.16 and 5.12 mg L- ornithine/kg fish tissue, 40.20 and 40.28 mg L-arginine/kg fish tissue), redness (4.86 and 5.33), yellowness (9.32 and 10.01), lipid oxidation (3.09 and 3.52 mg malondialdehyde/kg fish tissue) and protein oxidation (10.27 and 11.93 nmol carbonyls/mg protein), as well as lower hardness (1877.54 and 1767.39 g), respectively, than control fillets (p < 0.05). The combined preservation methods were the most effective in extending the shelf life and prolonging the physicochemical quality of the refrigerated tilapia fillets and the O2 scavenger proved to be a potential alternative to prevent the negative changes induced by both UV-C doses.
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Dong K, Pan H, Yang D, Rao L, Zhao L, Wang Y, Liao X. Induction, detection, formation, and resuscitation of viable but non‐culturable state microorganisms. Compr Rev Food Sci Food Saf 2019; 19:149-183. [DOI: 10.1111/1541-4337.12513] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 10/21/2019] [Accepted: 11/14/2019] [Indexed: 01/05/2023]
Affiliation(s)
- Kai Dong
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Hanxu Pan
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Dong Yang
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Lei Rao
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Liang Zhao
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Yongtao Wang
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Xiaojun Liao
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
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Murugan K, Vasudevan N. Intracellular toxicity exerted by PCBs and role of VBNC bacterial strains in biodegradation. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 157:40-60. [PMID: 29605643 DOI: 10.1016/j.ecoenv.2018.03.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 02/22/2018] [Accepted: 03/06/2018] [Indexed: 06/08/2023]
Abstract
Polychlorinated biphenyls (PCBs) are xenobiotic compounds that persists in the environment for long-term, though its productivity is banned. Abatement of the pollutants have become laborious due to it's recalcitrant nature in the environment leading to toxic effects in humans and other living beings. Biphenyl degrading bacteria co-metabolically degrade low chlorinated PCBs using the active metabolic pathway. bph operon possess different genetic arrangements in gram positive and gram negative bacteria. The binding ability of the genes and the active sites were determined by PCB docking studies. The active site of bphA gene with conserved amino acid residues determines the substrate specificity and biodegradability. Accumulation of toxic intermediates alters cellular behaviour, biomass production and downturn the metabolic activity. Several bacteria in the environment attain unculturable state which is viable and metabolically active but not cultivable (VBNC). Resuscitation-promoting factor (Rpf) and Rpf homologous protein retrieve the culturability of the so far uncultured bacteria. Recovery of this adaptive mechanism against various physical and chemical stressors make a headway in understanding the functionality of both environmental and medically important unculturable bacteria. Thus, this paper review about the general aspects of PCBs, cellular toxicity exerted by PCBs, role of unculturable bacterial strains in biodegradation, genes involved and degradation pathways. It is suggested to extrapolate the research findings on extracellular organic matters produced in culture supernatant of VBNC thus transforming VBNC to culturable state.
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Affiliation(s)
- Karuvelan Murugan
- Centre for Environmental Studies, Anna University, CEG Campus, Chennai, Tamil Nadu, India.
| | - Namasivayam Vasudevan
- Centre for Environmental Studies, Anna University, CEG Campus, Chennai, Tamil Nadu, India.
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Arroyo MG, Ferreira AM, Frota OP, Rigotti MA, de Andrade D, Brizzotti NS, Peresi JTM, Castilho EM, de Almeida MTG. Effectiveness of ATP bioluminescence assay for presumptive identification of microorganisms in hospital water sources. BMC Infect Dis 2017; 17:458. [PMID: 28666419 PMCID: PMC5493863 DOI: 10.1186/s12879-017-2562-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 06/22/2017] [Indexed: 11/10/2022] Open
Abstract
Background Laboratory analysis of organisms in water include arduous methods, such as the multiple tube and membrane filter. The ATP bioluminescence system, proposes a new way of measuring cellular material in water by measuring adenosine triphosphate (ATP) levels, which are expressed in relative light units (RLU). The ATP bioluminescence assay has been increasingly used to assess the microbiological safety of the hospital environment. However, there are few studies investigating the use of this methodology to evaluate the microbiological quality of water. The objective of the present study was to verify whether ATP, as measured by the 3 M™ Clean-Trace Water™ ATP test, can be used as an alternative tool for presumptive testing for the presence of microorganisms in hospital water. Methods Water samples (N = 88) were collected from faucets (74) and water purifiers (14) in a university hospital. The sample were filtered by the membrane filter technique (100 mL for bacterial analysis and 100 mL for fungal analysis) and then submitted to ATP bioluminescence assay to the determine quantity of RLU in each sample. In order to compare RLU and the presence of microorganisms, a receiver operating characteristic (ROC) curve was used to calculate sensitivity and specificity (levels higher than 90% were considered significant). In addition, control tests were conducted to compare RLU to the quantities of bacterial and fungal organisms added to distilled water (ANOVA and Tukey’s tests; p ≤ 0.05). This inoculum was compared to RLU emission, and the data were analyzed by calculating the Pearson’s correlation coefficient, with a 95% confidence interval. Results In the present study, 94.3% of the water samples presented bacterial growth. Of these, 15.6% showed heterotrophic bacteria above recommended levels and fungal contamination was detected in 55.6% of samples. Sensitivity and specificity of the samples were not significant (< 90%), and the correlation between ATP and the presence of these microorganisms in the samples (hospital water) was not significant, whereas, in distilled water, the results revealed a significant difference (p < 0.0001). Conclusions These results demonstrated that the ATP test cannot be used as an alternative tool for presumptive assessment of the presence of microorganisms in water.
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Affiliation(s)
- Máira Gazzola Arroyo
- Graduate Program in Microbiology, São Paulo State University, Street Cristóvão Colombo, 2265, 15054-000, São José do Rio Preto, São Paulo, Brazil.
| | - Adriano Menis Ferreira
- Master and Doctoral Graduate Program in Health and Development in the West Central Region and Master Graduate Program in Nursing, Federal University of Mato Grosso do Sul, Av. Costa and Silva, s/n, 79070-900, Campo Grande, Mato Grosso do Sul, Brazil
| | - Oleci Pereira Frota
- Master and Doctoral Graduate Program in Health and Development in the West Central Region and Master Graduate Program in Nursing, Federal University of Mato Grosso do Sul, Av. Costa and Silva, s/n, 79070-900, Campo Grande, Mato Grosso do Sul, Brazil
| | - Marcelo Alessandro Rigotti
- Undergraduate Program in Nursing, Federal University of Mato Grosso do Sul, Av. Ranulpho Marques Leal, 3484, 79610-100, Três Lagoas, Mato Grosso do Sul, Brazil
| | - Denise de Andrade
- Department of General and Specialized Nursing, Ribeirão Preto College of Nursing, WHO Collaborating Centre for Nursing Research Development, University of São Paulo, Av. Bandeirantes, 3900, 14040-902, Ribeirão Preto, São Paulo, Brazil
| | - Natalia Seron Brizzotti
- Department of Infectious and Parasitic Diseases, Faculty of Medicine of São José do Rio Preto, Av. Brg. Faria Lima, 5416, 15090-000, São José do Rio Preto, São Paulo, Brazil
| | - Jacqueline Tanury Macruz Peresi
- Center of Regional Laboratory of São José do Rio Preto, Adolfo Lutz Institute, Street Rua Alberto Sufredini Bertoni, 2325, 15060-020, São José do Rio Preto, São Paulo, Brazil
| | - Elza Maria Castilho
- Department of Infectious and Parasitic Diseases, Faculty of Medicine of São José do Rio Preto, Av. Brg. Faria Lima, 5416, 15090-000, São José do Rio Preto, São Paulo, Brazil
| | - Margarete Teresa Gottardo de Almeida
- Department of Infectious and Parasitic Diseases, Faculty of Medicine of São José do Rio Preto, Av. Brg. Faria Lima, 5416, 15090-000, São José do Rio Preto, São Paulo, Brazil
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Su X, Guo L, Ding L, Qu K, Shen C. Induction of Viable but Nonculturable State in Rhodococcus and Transcriptome Analysis Using RNA-seq. PLoS One 2016; 11:e0147593. [PMID: 26808070 PMCID: PMC4725852 DOI: 10.1371/journal.pone.0147593] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 01/06/2016] [Indexed: 11/23/2022] Open
Abstract
Viable but nonculturable (VBNC) bacteria, which maintain the viability with loss of culturability, universally exist in contaminated and non-contaminated environments. In this study, two strains, Rhodococcus sp. TG13 and TN3, which were isolated from PCB-contaminated sediment and non-contaminated sediment respectively, were investigated under low temperature and oligotrophic conditions. The results indicated that the two strains TG13 and TN3 could enter into the VBNC state with different incubation times, and could recover culturability by reversal of unfavourable factors and addition of resuscitation-promoting factor (Rpf), respectively. Furthermore, the gene expression variations in the VBNC response were clarified by Illumina high throughput RNA-sequencing. Genome-wide transcriptional analysis demonstrated that up-regulated genes in the VBNC cells of the strain TG13 related to protein modification, ATP accumulation and RNA polymerase, while all differentially expressed genes (DEGs) in the VBNC cells of the strain TN3 were down-regulated. However, the down-regulated genes in both the two strains mainly encoded NADH dehydrogenase subunit, catalase, oxidoreductase, which further verified that cold-induced loss of ability to defend oxidative stress may play an important role in induction of the VBNC state. This study further verified that the molecular mechanisms underlying the VBNC state varied with various bacterial species. Study on the VBNC state of non-pathogenic bacteria will provide new insights into the limitation of environmental micro-bioremediation and the cultivation of unculturable species.
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Affiliation(s)
- Xiaomei Su
- Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
- Key Laboratory for Water Pollution Control and Environmental Safety in Zhejiang Province, Hangzhou 310058, China
| | - Li Guo
- Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
- Key Laboratory for Water Pollution Control and Environmental Safety in Zhejiang Province, Hangzhou 310058, China
| | - Linxian Ding
- College of Geography and Environmental Science, Zhejiang Normal University, Jinhua 321004, China
| | - Kun Qu
- School of Medicine, Stanford Universtiy, Stanford, California 94305, USA
| | - Chaofeng Shen
- Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
- Key Laboratory for Water Pollution Control and Environmental Safety in Zhejiang Province, Hangzhou 310058, China
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Identification, characterization and molecular analysis of the viable but nonculturable Rhodococcus biphenylivorans. Sci Rep 2015; 5:18590. [PMID: 26687808 PMCID: PMC4685647 DOI: 10.1038/srep18590] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 11/20/2015] [Indexed: 01/26/2023] Open
Abstract
Numerous bacteria, including pollutant-degrading bacteria can enter the viable but nonculturable state (VBNC) when they encounter harsh environmental conditions. VBNC bacteria, as a vast majority of potent microbial resource can be of great significance in environmental rehabilitation. It is necessary to study the VBNC state of pollutant-degrading bacteria under various stress conditions. The aim of this study was to determine whether Rhodococcus biphenylivorans could enter the VBNC state under oligotrophic and low temperature conditions, and to examine the changes of morphology, enzymatic activity and gene expressions that might underline such state. The obtained results indicated that R. biphenylivorans TG9(T) could enter into the VBNC state and recover culturability under favorable environmental conditions. Results from Illumina high throughput RNA-sequencing revealed that the up-regulated genes related to ATP accumulation, protein modification, peptidoglycan biosynthesis and RNA polymerase were found in the VBNC cells, and the down-regulated genes mainly encoded hypothetical protein, membrane protein and NADH dehydrogenase subunit, which render VBNC cells more tolerant to survive under inhospitable conditions. This study provides new insights into prevention and control of the VBNC state of pollutant-degrading bacteria for their better capabilities in environmental rehabilitation.
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Jones TH, Vail KM, McMullen LM. Filament formation by foodborne bacteria under sublethal stress. Int J Food Microbiol 2013; 165:97-110. [PMID: 23727653 DOI: 10.1016/j.ijfoodmicro.2013.05.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 04/26/2013] [Accepted: 05/01/2013] [Indexed: 11/28/2022]
Abstract
A number of studies have reported that pathogenic and nonpathogenic foodborne bacteria have the ability to form filaments in microbiological growth media and foods after prolonged exposure to sublethal stress or marginal growth conditions. In many cases, nucleoids are evenly spaced throughout the filamentous cells but septa are not visible, indicating that there is a blockage in the early steps of cell division but the mechanism behind filament formation is not clear. The formation of filamentous cells appears to be a reversible stress response. When filamentous cells are exposed to more favorable growth conditions, filaments divide rapidly into a number of individual cells, which may have major health and regulatory implications for the food industry because the potential numbers of viable bacteria will be underestimated and may exceed tolerated levels in foods when filamentous cells that are subjected to sublethal stress conditions are enumerated. Evidence suggests that filament formation under a number of sublethal stresses may be linked to a reduced energy state of bacterial cells. This review focuses on the conditions and extent of filament formation by foodborne bacteria under conditions that are used to control the growth of microorganisms in foods such as suboptimal pH, high pressure, low water activity, low temperature, elevated CO2 and exposure to antimicrobial substances as well as lack a of nutrients in the food environment and explores the impact of the sublethal stresses on the cell's inability to divide.
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Affiliation(s)
- Tineke H Jones
- Agriculture and Agri-Food Canada, Lacombe Research Centre, 6000 C&E Trail, Lacombe, Alberta T4L 1W1, Canada.
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13
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Studies on the pathogenesis and survival of different culture forms of Listeria monocytogenes to pulsed UV-light irradiation after exposure to mild-food processing stresses. Food Microbiol 2012; 30:330-9. [DOI: 10.1016/j.fm.2011.12.024] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 12/27/2011] [Accepted: 12/28/2011] [Indexed: 12/22/2022]
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14
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Shama G, Malik DJ. The uses and abuses of rapid bioluminescence-based ATP assays. Int J Hyg Environ Health 2012; 216:115-25. [PMID: 22541898 DOI: 10.1016/j.ijheh.2012.03.009] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 03/20/2012] [Accepted: 03/20/2012] [Indexed: 01/19/2023]
Abstract
Bioluminescence-based ATP testing of solid surfaces has become well established in the food processing industry as part of general hazard analysis and critical control points (HACCP) measures. The rise in healthcare associated infections (HAIs) at the turn of the century focussed attention on the environment as a potential reservoir of the agents responsible for such infections. In response to the need for objective methods of assessing the efficiency of cleaning in healthcare establishments and for rapid methods for detecting the presence of the pathogens responsible for HAIs, it was proposed that ATP testing of environmental surfaces be introduced. We examine the basis behind the assumptions inherent in these proposals. Intracellular ATP levels are shown to vary between microbial taxa and according to environmental conditions. Good correlations between microbial numbers and ATP levels have been obtained under certain specific conditions, but never within healthcare settings. Notwithstanding, ATP testing may still have a role in providing reassurance that cleaning regimes are being carried out satisfactorily. However, ATP results should not be interpreted as surrogate indicators for the presence of microbial pathogens.
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Affiliation(s)
- G Shama
- Department of Chemical Engineering, Loughborough University, Loughborough LE11 3TU, United Kingdom.
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Nicolò MS, Gioffrè A, Carnazza S, Platania G, Silvestro ID, Guglielmino SPP. Viable But Nonculturable State of Foodborne Pathogens in Grapefruit Juice: A Study of Laboratory. Foodborne Pathog Dis 2011; 8:11-7. [DOI: 10.1089/fpd.2009.0491] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Marco Sebastiano Nicolò
- Dipartimento di Scienze della Vita “Marcello Malpighi,” Sezione di Scienze Microbiologiche, Genetiche e Molecolari, Università di Messina, Messina, Italy
| | - Angela Gioffrè
- Dipartimento di Scienze della Vita “Marcello Malpighi,” Sezione di Scienze Microbiologiche, Genetiche e Molecolari, Università di Messina, Messina, Italy
| | - Santina Carnazza
- Dipartimento di Scienze della Vita “Marcello Malpighi,” Sezione di Scienze Microbiologiche, Genetiche e Molecolari, Università di Messina, Messina, Italy
| | - Giuseppe Platania
- A.A.T. SpA—Agroindustry Advanced Technologies, Contrada Zona Industriale Blocco Palma I, Catania, Italy
| | - Isabella Di Silvestro
- A.A.T. SpA—Agroindustry Advanced Technologies, Contrada Zona Industriale Blocco Palma I, Catania, Italy
| | - Salvatore Pietro Paolo Guglielmino
- Dipartimento di Scienze della Vita “Marcello Malpighi,” Sezione di Scienze Microbiologiche, Genetiche e Molecolari, Università di Messina, Messina, Italy
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Lindbäck T, Rottenberg ME, Roche SM, Rørvik LM. The ability to enter into an avirulent viable but non-culturable (VBNC) form is widespread among Listeria monocytogenes isolates from salmon, patients and environment. Vet Res 2009; 41:8. [PMID: 19796607 PMCID: PMC2775167 DOI: 10.1051/vetres/2009056] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Accepted: 09/30/2009] [Indexed: 11/14/2022] Open
Abstract
Media-based bacteriological testing will fail to detect non-culturable organisms and the risk of consuming viable but non-culturable (VBNC) Listeria monocytogenes is unknown. We have here studied whether L. monocytogenes obtained from seafoods, processing environment and clinical cases enter the VBNC state and assessed the virulence of the non-culturable forms of the bacteria. A number of 16 L. monocytogenes strains were starved in microcosm water at 4 °C until loss of culturability. Metabolic activity in the VBNC form was measured as ATP generation using a luciferase assay and membrane integrity was examined using the LIVE/DEAD BacLight assay. All tested L. monocytogenes strains entered the VBNC state after starvation in microcosm water. Ongoing mRNA synthesis of hly in VBNC L. monocytogenes cells re-incubated in culture medium indicated a potential virulence of these forms. Sodium pyruvate and replenishment of nutrient were used in attempts to resuscitate VBNC cells. However, VBNC L. monocytogenes were not resuscitated under these conditions. VBNC L. monocytogenes were tested for virulence in a cell plaque assay and by intraperitoneally inoculation in immunodeficient RAG1−/− mice. Inoculation of VBNC L. monocytogenes in immunodeficient mice did not cause morbidity, and plaque assay on HT-29 cells in culture indicated that the VBNC cells were avirulent. The results indicate that the risk of non-culturable L. monocytogenes in foods, when the VBNC state is induced by starvation, is negligible.
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Affiliation(s)
- Toril Lindbäck
- Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, Oslo, Norway.
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Rowan NJ, Kirf D, Tomkins P. Studies on the susceptibility of different culture morphotypes of Listeria monocytogenes to uptake and survival in human polymorphonuclear leukocytes. ACTA ACUST UNITED AC 2009; 57:183-92. [PMID: 19735470 DOI: 10.1111/j.1574-695x.2009.00597.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study demonstrated that atypical virulent filaments of Listeria monocytogenes (rough variant type II and designated FR for this study), isolated from clinical specimens or generated during exposure to pulsed-plasma gas discharge in liquids, were shown to be capable of survival when engulfed by human polymorphonuclear leukocytes (PMNLs). Factors shown to significantly influence the maximal respiratory burst response in PMNLs and survival of different internalized cell or filament forms of L. monocytogenes were bacterial strain, culture form, degree of opsonization (with and without the use of 10% serum) and composition of the bacterial growth media used before uptake by PMNLs. Opsonized regular-sized L. monocytogenes cells grown on blood agar (BA) elicited the greatest respiratory burst response and survived best in PMNLs. The filamentous (FR) and multiple cell chain (MCR) rough variants were significantly less susceptible to uptake and survival in PMNLs. Supplementation of tryptone soya agar with hemin resulted in significantly reduced chemiluminescence responses in phagocytosing PMNLs compared with the maximal levels observed from prior bacterial growth on BA or brain heart infusion agar that also contained a source of iron. The MCR variants secreting decreased levels of a peptidoglycan hydrolase CwhA protein exhibited the lowest percentage survival when internalized in PMNLs compared with wild-type smooth or FR culture variants as determined by the macrophage-killing assay.
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Affiliation(s)
- Neil J Rowan
- Department of Nursing and Health Science, Athlone Institute of Technology, Athlone, Ireland.
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Saroj S, Shashidhar R, Bandekar J. Gamma radiation used as hygienization technique for foods does not induce viable but non-culturable state (VBNC) in Salmonella enterica subsp. enterica serovar Typhimurium. Curr Microbiol 2009; 59:420-4. [PMID: 19641961 DOI: 10.1007/s00284-009-9454-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2008] [Revised: 05/25/2009] [Accepted: 07/01/2009] [Indexed: 11/24/2022]
Abstract
Gamma radiation has been widely used for hygienization of food products. Whether gamma radiation stress induces VBNC state in Salmonella is of great concern. Therefore, the study was carried out to determine whether gamma radiation exposure induces VBNC state in Salmonella enterica subsp. enterica serovar Typhimurium (S. typhimurium). The parameters tested were culturability on agar medium, transcriptional activity by RT-PCR, cytoplasmic membrane integrity, and direct viable count using LIVE/DEAD BacLight bacterial viability kit. The LIVE/DEAD BacLight counts for S. typhimurium cells treated with 0.5 and 1.0 kGy radiation dose were 0.8 and 0.1% of the control, respectively. Plate counts for S. typhimurium cells treated with 0.5 and 1.0 kGy radiation dose were 0.7 and 0.05% of the control, respectively. No viable cells of S. typhimurium were detected by both plate count and LIVE/DEAD BacLight after radiation treatment with 2 kGy. No transcriptional activity was detected in cells treated with 2 kGy radiation dose. If there were VBNC cells present, then significant differences in the counts between the LIVE/DEAD BacLight microscopic counts and plate agar counts must be observed. No significant difference (P > 0.05) in the counts were observed. Thus, it can be concluded that treatment with 2 kGy results in complete killing and does not induce VBNC state in S. typhimurium.
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Affiliation(s)
- Sunil Saroj
- Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
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Dinu LD, Delaquis P, Bach S. Nonculturable response of animal enteropathogens in the agricultural environment and implications for food safety. J Food Prot 2009; 72:1342-54. [PMID: 19610353 DOI: 10.4315/0362-028x-72.6.1342] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Concerns about animal enteropathogen contamination of fresh horticultural products have,increased worldwide and are mainly due to the ability of bacteria to survive under stress conditions in the agricultural environment and during raw-vegetable processing. This review challenges the idea that the viable but nonculturable phenomenon that has been proven to occur in plant-associated environments contributes to human pathogen survival and might be correlated with foodborne infection. Factors associated with the nonculturable response of bacteria in the field and during postharvest processing and distribution are discussed, specifically for the most common animal enteropathogens linked with the consumption of raw products: Escherichia coli O157:H7, Salmonella, Listeria monocytogenes, and Shigella spp. The accurate detection of live bacterial populations is essential for pathogen screening in food and environmental safety control and in epidemiological analysis and may have to be considered for identification of critical control points at the time of food inspection.
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Affiliation(s)
- Laura-Dorina Dinu
- Agriculture and Agri-Food Canada, Pacific Agri-Food Research Centre, 4200 Highway 97 South, Summerland, British Columbia, Canada
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Van Houteghem N, Devlieghere F, Rajkovic A, Gómez SMO, Uyttendaele M, Debevere J. Effects of CO2 on the resuscitation of Listeria monocytogenes injured by various bactericidal treatments. Int J Food Microbiol 2007; 123:67-73. [PMID: 18230409 DOI: 10.1016/j.ijfoodmicro.2007.12.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Revised: 12/04/2007] [Accepted: 12/04/2007] [Indexed: 11/16/2022]
Abstract
To assure the microbiological safety and quality of a food product, a combination of preservation hurdles is often used. Therefore, the effects of carbon dioxide at concentrations of 0, 20, 40 and 60% in modified atmospheres on the resuscitation of Listeria monocytogenes cells injured by mild bactericidal treatments during storage at 7 degrees C were examined. The bactericidal treatments were intense light pulses (ILP), chlorine dioxide (ClO(2)), lactic acid (LA) and heat. The results indicated additional bactericidal effects of CO(2) on cultures treated with LA, ClO(2) and ILP, with additional reductions in viable L. monocytogenes of 0.5-1.0 log cfu/ml. Lag phase duration was significantly different between the different treatments, with non-treated cells having the shortest lag phase, followed by that of heat, intense light pulses, lactic acid and finally ClO(2) treated cells. Maximum growth rate was also estimated and results showed a negative correlation with increasing CO(2) concentrations. A relationship was found between the amount of sub-lethally damaged cells after a mild inactivation treatment and the lag phase duration in the CO(2) environment. Current findings demonstrate the possibility that combining mild decontamination treatments and packaging in a CO(2) enriched environment could reduce the risk of L. monocytogenes infections in food due to an extension of the lag phase.
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Affiliation(s)
- Nancy Van Houteghem
- Department of Food Safety and Food Quality, Laboratory of Food Microbiology and Food Preservation, Ghent University, Coupure links 653, B-9000 Ghent, Belgium
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Giotis ES, Blair IS, McDowell DA. Morphological changes in Listeria monocytogenes subjected to sublethal alkaline stress. Int J Food Microbiol 2007; 120:250-8. [DOI: 10.1016/j.ijfoodmicro.2007.08.036] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2007] [Accepted: 08/28/2007] [Indexed: 11/30/2022]
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Hazeleger WC, Dalvoorde M, Beumer RR. Fluorescence microscopy of NaCl-stressed, elongated Salmonella and Listeria cells reveals the presence of septa in filaments. Int J Food Microbiol 2006; 112:288-90. [PMID: 16806551 DOI: 10.1016/j.ijfoodmicro.2006.04.026] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/26/2006] [Indexed: 11/30/2022]
Abstract
The cell morphology of Salmonella enteritidis and Listeria monocytogenes after the application of stress was examined. Cells were stressed by plating the bacteria on Tryptone Soya Agar (TSA) plates, with 5-10% NaCl. The plates were subsequently incubated for 6 days at 25 degrees C. Finally, the cells were harvested and subjected to different fluorescent probes in order to visualize the possible presence of septa in elongated cells. Use of the stain 4',6-Diamidino-2-phenylindole (DAPI), which is a blue fluorescent nucleic acid stain that preferentially stains double-stranded DNA, showed clearly the presence of dark spots, probably cellular partitions where no nucleic acids were present, in both Salmonella and Listeria cells. Another stain, FM 4-64, a lipophilic styryl dye for red staining of the inner membrane, showed the presence of highly fluorescent spots in Listeria cells, probably indicating the presence of membranes. For Salmonella, however, FM 4-64 was not successful in revealing septa in filaments. Double staining applied to elongated Listeria cells showed areas with high fluorescence in DAPI-staining (DNA-rich spots) which contained low fluorescence in FM 4-64-staining (membrane spots) and vice versa, which is a confirmation that the elongated cells are indeed composed of several normal size cells.
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Affiliation(s)
- Wilma C Hazeleger
- Laboratory of Food Microbiology, Wageningen University, 6700 EV Wageningen, The Netherlands.
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Ercolini D, Storia A, Villani F, Mauriello G. Effect of a bacteriocin-activated polythene film on Listeria monocytogenes as evaluated by viable staining and epifluorescence microscopy. J Appl Microbiol 2006; 100:765-72. [PMID: 16553731 DOI: 10.1111/j.1365-2672.2006.02825.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
AIMS To evaluate the effect of a bacteriocin-activated polythene film on resting and growing populations of Listeria monocytogenes. METHODS AND RESULTS The active polythene films were industrially obtained by coating a solution of bacteriocin 32Y from Lactobacillus curvatus upon the surface of the film to be in contact with the packaged material. The behaviour of live Listeria populations was examined in liquid suspensions directly in contact with the bacteriocin-activated film, packed in antimicrobial film, and in a challenge test of storage of frankfurters superficially contaminated by L. monocytogenes and packed in antimicrobial film. In all the experiments, live and dead cells of L. monocytogenes were counted in epifluorescence microscopy after viable staining, which proved to be a suitable method to evaluate the action of bacteriocins on populations of L. monocytogenes. The results showed that the direct contact between active film surface and L. monocytogenes cells is effective for a fast and irreversible inactivation of the population by determining a direct cell disruption. This was confirmed by the results of the challenge test indicating that the antimicrobial package was effective in inhibiting the growth and survival of the pathogen on the surface of frankfurters during storage. CONCLUSIONS The use of the antimicrobial film is encouraged especially for solid food products where the superficial contaminants come immediately in contact with the antimicrobial film. SIGNIFICANCE AND IMPACT OF THE STUDY A fast inactivation of the bacterial population, coupled with appropriate conditions of storage, can improve the quality and safety and prolong the shelf-life of the food products packed in antimicrobial films.
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Affiliation(s)
- D Ercolini
- Dipartimento di Scienza degli Alimenti, Università degli Studi di Napoli, Federico II, Naples, Italy
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Jydegaard-Axelsen AM, Aaes-Jørgensen A, Koch AG, Jensen JS, Knøchel S. Changes in growth, rRNA content, and cell morphology of Listeria monocytogenes induced by CO2 up- and downshift. Int J Food Microbiol 2005; 98:145-55. [PMID: 15681042 DOI: 10.1016/j.ijfoodmicro.2004.05.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2003] [Revised: 04/23/2004] [Accepted: 05/26/2004] [Indexed: 11/21/2022]
Abstract
Cell morphology, rRNA content, and growth were examined for Listeria monocytogenes LO28 and EGD, respectively, grown in brain-heart infusion (BHI) and on slices of sausage at 10 degrees C in 100% CO2, 100% N2, and air. In CO2, filamentous cells were formed by both strains on sausage slices and by L. monocytogenes EGD in BHI. Filamentation was not induced by anaerobiosis only. Fluorescent in situ rRNA hybridization (FISH) of cells grown in BHI showed that the L. monocytogenes EGD filaments consisted of chains of individual slightly elongated cells. The rods formed by L. monocytogenes LO28 had the same size in air and CO2. Septation and cell division were induced in the filaments after a CO2 downshift (i.e., exposure to air). In BHI, the number of colony forming units increased rapidly when L. monocytogenes EGD grown in CO2 was exposed to air whereas the number of L. monocytogenes LO28 remained almost unchanged. On sausage slices, the number of colony forming units also increased rapidly for both strains in response to CO2 downshift. Large variations in rRNA content of individual cells were observed in the tested scenarios. The results demonstrate the risk of underestimating the number of infectious units under circumstances where filamentation may occur. Furthermore, the study illustrates the lack of residual inhibitory effect of CO2 in this type of products after opening.
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Affiliation(s)
- Anne-Marie Jydegaard-Axelsen
- Department of Food Science, The Royal Veterinary and Agricultural University, Rolighedsvej 30, 1958 Frederiksberg C, Denmark
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