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Dorbani I, Berberian A, Riedel C, Duport C, Carlin F. Comparing resistance of bacterial spores and fungal conidia to pulsed light and UVC radiation at a wavelength of 254 nm. Food Microbiol 2024; 121:104518. [PMID: 38637080 DOI: 10.1016/j.fm.2024.104518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 02/28/2024] [Accepted: 03/08/2024] [Indexed: 04/20/2024]
Abstract
Pulsed light (PL) inactivates microorganisms by UV-rich, high-irradiance and short time pulses (250 μs) of white light with wavelengths from 200 nm to 1100 nm. PL is applied for disinfection of food packaging material and food-contact equipment. Spores of seven Bacillus ssp. strains and one Geobacillus stearothermophilus strain and conidia of filamentous fungi (One strain of Aspergillus brasiliensis, A. carbonarius and Penicillium rubens) were submitted to PL (fluence from 0.23 J/cm2 to 4.0 J/cm2) and UVC (at λ = 254 nm; fluence from 0.01 J/cm2 to 3.0 J/cm2). One PL flash at 3 J/cm2 allowed at least 3 log-reduction of all tested microorganisms. The emetic B. cereus strain F4810/72 was the most resistant of the tested spore-forming bacteria. The PL fluence to 3 log-reduction (F3 PL) of its spores suspended in water was 2.9 J/cm2 and F3 UVC was 0.21 J/cm2, higher than F3 PL and F3 UVC of spores of B. pumilus SAFR-032 2.0 J/cm2 and 0.15 J/cm2, respectively), yet reported as a highly UV-resistant spore-forming bacterium. PL and UVC sensitivity of bacterial spores was correlated. Aspergillus spp. conidia suspended in water were poorly sensitive to PL. In contrast, PL inactivated Aspergillus spp. conidia spread on a dry surface more efficiently than UVC. The F2 PL of A. brasiliensis DSM1988 was 0.39 J/cm2 and F2 UVC was 0.83 J/cm2. The resistance of spore-forming bacteria to PL could be reasonably predicted from the knowledge of their UVC resistance. In contrast, the sensitivity of fungal conidia to PL must be specifically explored.
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Affiliation(s)
- Imed Dorbani
- INRAE, Avignon Université, UMR SQPOV, Avignon, France; Claranor, 862 Rue André-Jean Boudoy, 84140, Avignon, France
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Gandhi J, Prakash H. Photo-disinfection Processes for Bacterial Inactivation and Underlying Principles for Water Constituents’ Impact: A Review. CHEMICAL ENGINEERING JOURNAL ADVANCES 2023. [DOI: 10.1016/j.ceja.2023.100482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023] Open
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Wang Z, Tang WZ, Sillanpää M, Li J. UV Disinfection sensitivity index of spores or protozoa: A model to predict the required fluence of spores or protozoa. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2022; 86:2820-2833. [PMID: 36515191 DOI: 10.2166/wst.2022.391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
During UV disinfection, the required UV dose in terms of fluence depends upon the species of bacteria spore and protozoa. To rank their UV disinfection sensitivity, spore sensitivity index (SPSI) and protozoan sensitivity index (PSI) are defined. For spores, shoulder effect exists, therefore, SPSI is defined as the ratio between the ki of any spores for the linear portion of the dose response curve to the kir of Bacillus subtilis as the reference spore. After statistical analysis, the fluence of any spore can be predicted by SPSI through equation, H = (0.8358 ± 0.126)*LogI*SPSI + H0. PSI is defined as the ratio between the inactivation rate constants of a protozoa in reference to that of Cryptosporidium parvum. The equation predicting the fluence of any protozoa in reference to Cryptosporidium parvum is: H = 107.45*(3.86 ± 2.68)*LogI/PSI. Two regression equations suggest that protozoa require significantly higher UV dose than bacteria spores.
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Affiliation(s)
- Zhao Wang
- Laboratory of Green Chemistry, School of Engineering Science, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli, Finland
| | - Walter Z Tang
- Department of Civil and Environmental Engineering, Florida International University, Miami, FL 33174, USA E-mail:
| | - Mika Sillanpää
- Institute of Research and Development, Duy Tan University, Da Nang 550000, Vietnam; Faculty of Environment and Chemical Engineering, Duy Tan University, Da Nang 550000, Vietnam; School of Civil Engineering and Surveying, Faculty of Health, Engineering and Sciences, University of Southern Queensland, West Street, Toowoomba, 4350 QLD, Australia; Department of Chemical Engineering, School of Mining, Metallurgy and Chemical Engineering, University of Johannesburg, P. O. Box 17011, Doornfontein 2028, South Africa
| | - Jinze Li
- Department of Civil and Environmental Engineering, Florida International University, Miami, FL 33174, USA E-mail:
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Rubio-Clemente A, Chica E, Peñuela G. Evaluation of the UV/H 2O 2 system for treating natural water with a mixture of anthracene and benzo[a]pyrene at ultra-trace levels. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:4381-4392. [PMID: 29872982 DOI: 10.1007/s11356-018-2411-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 05/24/2018] [Indexed: 06/08/2023]
Abstract
The presence of polycyclic aromatic hydrocarbons, such as anthracene (AN) and benzo[a]pyrene (BaP), in water has become a problem of great concern due to the detrimental health effects caused to humans and living beings. In this work, the efficiency of the UV/H2O2 system for degrading the target compounds at ultra-trace levels in surface water has been evaluated. For this purpose, a previous optimization step using a face-centered central composite experimental design has been conducted, considering the effect of the UV-C irradiance and the initial concentration of H2O2. It was evidenced that under optimal operating conditions (11 mg L-1 H2O2 and 0.63 mW cm-2 irradiance), AN and BaP removal percentages were higher than 99.8%. Additionally, 69.3% of the organic matter, in terms of total organic carbon, was mineralized without the production of transformation by-products more harmful than the parent compounds. These findings demonstrate the oxidation capacity of the examined system in a natural matrix for degrading micropollutants that cannot be converted through conventional treatment processes. Consequently, new horizons are opened for the effective use of the UV/H2O2 system for drinking water production, providing the accomplishment of other regulated parameters related to water quality.
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Affiliation(s)
- Ainhoa Rubio-Clemente
- Facultad de Ciencias de la Salud, Universidad Católica de Murcia UCAM, Avenida de los Jerónimos, s/n, Murcia, Spain.
- Grupo GDCON, Facultad de Ingeniería, Sede de Investigaciones Universitarias (SIU), Universidad de Antioquia UdeA, Calle 70, No. 52-51, Medellín, Colombia.
- Facultad de Ingeniería, Tecnológico de Antioquia-Institución Universitaria TdeA, Calle 78b, No. 72A-220, Medellín, Colombia.
| | - Edwin Chica
- Departamento de Ingeniería Mecánica, Facultad de Ingeniería, Universidad de Antioquia UdeA, Calle 70, No. 52-51, Medellín, Colombia
| | - Gustavo Peñuela
- Grupo GDCON, Facultad de Ingeniería, Sede de Investigaciones Universitarias (SIU), Universidad de Antioquia UdeA, Calle 70, No. 52-51, Medellín, Colombia
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Aguilar S, Rosado D, Moreno-Andrés J, Cartuche L, Cruz D, Acevedo-Merino A, Nebot E. Inactivation of a wild isolated Klebsiella pneumoniae by photo-chemical processes: UV-C, UV-C/H2O2 and UV-C/H2O2/Fe3+. Catal Today 2018. [DOI: 10.1016/j.cattod.2017.10.043] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Guo S, Huang R, Chen H. Application of water-assisted ultraviolet light in combination of chlorine and hydrogen peroxide to inactivate Salmonella on fresh produce. Int J Food Microbiol 2017; 257:101-109. [PMID: 28651076 DOI: 10.1016/j.ijfoodmicro.2017.06.017] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 05/17/2017] [Accepted: 06/18/2017] [Indexed: 11/23/2022]
Abstract
With the demand for fresh produce increases in recent decades, concerns for microbiological safety of fresh produce are also raised. To identify effective ultraviolet (UV) light treatment for fresh produce decontamination, we first determined the effect of three forms of UV treatment, dry UV (samples were treated by UV directly), wet UV (samples were dipped in water briefly and then exposed to UV), and water-assisted UV (samples were treated by UV while being immersed in agitated water) on inactivation of Salmonella inoculated on tomatoes and fresh-cut lettuce. In general, the water-assisted UV treatment was found to be the most effective for both produce items. Chlorine and hydrogen peroxide were then tested to determine whether they could be used to enhance the decontamination efficacy of water-assisted UV treatment and prevent transfer of Salmonella via wash water by completely eliminating it. Neither of them significantly enhanced water-assisted UV inactivation of Salmonella on tomatoes. Chlorine significantly improved the decontamination effectiveness of the water-assisted UV treatment for baby-cut carrots and lettuce, but not for spinach. In general, the single water-assisted UV treatment and the combined treatment of water-assisted UV and chlorine were similar or more effective than the chlorine washing treatment. In most of the cases, no Salmonella was detected in the wash water when the single water-assisted UV treatment was used to decontaminate tomatoes. In a few cases when Salmonella was detected in the wash water, the populations were very low,≤2CFU/mL, and the wash water contained an extremely high level of organic load and soil level. Therefore, the single water-assisted UV treatment could potentially be used as an environmentally friendly and non-chemical alternative to chlorine washing for tomatoes after validation in industrial scale. For lettuce, spinach and baby-cut carrots, the combined treatment of water-assisted UV treatment and chlorine was needed to maintain a pathogen free environment in the wash water so that cross contamination could be prevented during fresh produce washing.
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Affiliation(s)
- Shuanghuan Guo
- Department of Animal and Food Sciences, University of Delaware, Newark, DE 19716-2150, USA
| | - Runze Huang
- Department of Animal and Food Sciences, University of Delaware, Newark, DE 19716-2150, USA
| | - Haiqiang Chen
- Department of Animal and Food Sciences, University of Delaware, Newark, DE 19716-2150, USA.
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