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Dias T, Santos VS, Zorgani T, Ferreiro N, Rodrigues AI, Zaghdoudi K, Veloso ACA, Peres AM. A Lab-Made E-Nose-MOS Device for Assessing the Bacterial Growth in a Solid Culture Medium. BIOSENSORS 2022; 13:19. [PMID: 36671854 PMCID: PMC9855957 DOI: 10.3390/bios13010019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 12/02/2022] [Accepted: 12/22/2022] [Indexed: 06/17/2023]
Abstract
The detection and level assessment of microorganisms is a practical quality/contamination indicator of food and water samples. Conventional analytical procedures (e.g., culture methods, immunological techniques, and polymerase chain reactions), while accurate and widely used, are time-consuming, costly, and generate a large amount of waste. Electronic noses (E-noses), combined with chemometrics, provide a direct, green, and non-invasive assessment of the volatile fraction without the need for sample pre-treatments. The unique olfactory fingerprint generated during each microorganism's growth can be a vehicle for its detection using gas sensors. A lab-made E-nose, comprising metal oxide semiconductor sensors was applied, to analyze solid medium containing Gram-positive (Enterococcus faecalis and Staphylococcus aureus) or Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. The electrical-resistance signals generated by the E-nose coupled with linear discriminant analysis allowed the discrimination of the four bacteria (90% of correct classifications for leave-one-out cross-validation). Furthermore, multiple linear regression models were also established allowing quantifying the number of colony-forming units (CFU) (0.9428 ≤ R2 ≤ 0.9946), with maximum root mean square errors lower than 4 CFU. Overall, the E-nose showed to be a powerful qualitative-quantitative device for bacteria preliminary analysis, being envisaged its possible application in solid food matrices.
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Affiliation(s)
- Teresa Dias
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal
- Laboratório Associado para a Sustentabilidade e Tecnologia em Região de Montanha (SusTEC), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal
| | - Vítor S. Santos
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal
- Laboratório Associado para a Sustentabilidade e Tecnologia em Região de Montanha (SusTEC), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal
- Departamento de Medicina Veterinária, Universidade Federal de Mato Grosso, Campus Sinop, Avenida Alexandre Ferronato, nº 1200, Bairro Residencial Cidade Jardim, Sinop 78550-728, MT, Brazil
| | - Tarek Zorgani
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal
- Laboratório Associado para a Sustentabilidade e Tecnologia em Região de Montanha (SusTEC), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal
- Département Génie Chimique, Université Libre de Tunis, Avenue Khéreddine—Pacha Tunis, 30, Tunis 1002, Tunisia
| | - Nuno Ferreiro
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal
- Laboratório Associado para a Sustentabilidade e Tecnologia em Região de Montanha (SusTEC), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal
| | - Ana I. Rodrigues
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal
- Laboratório Associado para a Sustentabilidade e Tecnologia em Região de Montanha (SusTEC), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal
| | - Khalil Zaghdoudi
- Département Génie Chimique, Université Libre de Tunis, Avenue Khéreddine—Pacha Tunis, 30, Tunis 1002, Tunisia
| | - Ana C. A. Veloso
- Instituto Politécnico de Coimbra, ISEC, DEQB, Rua Pedro Nunes, Quinta da Nora, 3030-199 Coimbra, Portugal
- CEB—Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
- LABBELS–Associate Laboratory, 4800-058 Braga/Guimarães, Portugal
| | - António M. Peres
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal
- Laboratório Associado para a Sustentabilidade e Tecnologia em Região de Montanha (SusTEC), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal
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Farjami A, Jalilzadeh S, Siahi-Shadbad M, Lotfipour F. The anti-biofilm activity of hydrogen peroxide against Escherichia coli strain FL-Tbz isolated from a pharmaceutical water system. JOURNAL OF WATER AND HEALTH 2022; 20:1497-1505. [PMID: 36308494 DOI: 10.2166/wh.2022.061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Biofilms are considered a significant reason for the failure of disinfection strategies in industrial water systems due to their resistance to antimicrobial agents. This study is designed to investigate the anti-biofilm activity of hydrogen peroxide (H2O2) at combinations of temperatures and contact times. For this purpose, an in vitro microtiter plate (MTP)-based model system was used for biofilm formation using Escherichia coli (E. coli) strain FL-Tbz isolated from the water system of a pharmaceutical plant. To investigate the anti-biofilm activity of H2O2, it was added at different concentrations (2-7% v/v) to biofilms and incubated at different temperatures (20-60 °C) for 10-40 min to find effective conditions to eradicate biofilms. Maximum biofilms were formed when bacterial suspensions were incubated at 37 °C for 96 h. The rate of biofilm formation using an environmental isolate was higher than that of standard strain. H2O2 at concentrations of ≥6.25% (v/v) at temperatures of ≥40 °C incubated for ≥25 min significantly eradicated the biofilms.
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Affiliation(s)
- Afsaneh Farjami
- Food and Drug Safety Research Center, Tabriz University of Medical Sciences, Tabriz, Iran E-mail: ; Pharmaceutical Analysis Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Sina Jalilzadeh
- Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammadreza Siahi-Shadbad
- Food and Drug Safety Research Center, Tabriz University of Medical Sciences, Tabriz, Iran E-mail: ; Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Farzaneh Lotfipour
- Food and Drug Safety Research Center, Tabriz University of Medical Sciences, Tabriz, Iran E-mail: ; Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
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Abstract
A lab-made electronic nose (Enose) with vacuum sampling and a sensor array, comprising nine metal oxide semiconductor Figaro gas sensors, was tested for the quantitative analysis of vapor–liquid equilibrium, described by Henry’s law, of aqueous solutions of organic compounds: three alcohols (i.e., methanol, ethanol, and propanol) or three chemical compounds with different functional groups (i.e., acetaldehyde, ethanol, and ethyl acetate). These solutions followed a fractional factorial design to guarantee orthogonal concentrations. Acceptable predictive ridge regression models were obtained for training, with RSEs lower than 7.9, R2 values greater than 0.95, slopes varying between 0.84 and 1.00, and intercept values close to the theoretical value of zero. Similar results were obtained for the test data set: RSEs lower than 8.0, R2 values greater than 0.96, slopes varying between 0.72 and 1.10, and some intercepts equal to the theoretical value of zero. In addition, the total mass of the organic compounds of each aqueous solution could be predicted, pointing out that the sensors measured mainly the global contents of the vapor phases. The satisfactory quantitative results allowed to conclude that the Enose could be a useful tool for the analysis of volatiles from aqueous solutions containing organic compounds for which Henry’s law is applicable.
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Tap versus Bottled Water in Kampala, Uganda: Analyses of Consumers’ Perception alongside Bacteriological and Physicochemical Quality. JOURNAL OF ENVIRONMENTAL AND PUBLIC HEALTH 2022; 2022:9336247. [PMID: 35712041 PMCID: PMC9197662 DOI: 10.1155/2022/9336247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 03/24/2022] [Accepted: 04/11/2022] [Indexed: 11/17/2022]
Abstract
In Uganda, tap water is always ensured to be potable. However, people are not sure whether tap water is generally safe for drinking without being boiled. Conversely, bottled water consumption is on the increase in Uganda. The main problem lies in the cost of energy for boiling tap water or purchasing bottled water. This study analyzed results of laboratory tests and consumers’ perception for comparison of tap and bottled water in Nakawa division, Kampala. Tap water was sampled at four representative locations. At least 16 different brands of bottled water were considered. The top four most consumer-preferred bottled water brands were selected for further analysis. In our study, 28.8%, 6.06%, and 13.64% of the 142 respondents indicated that bottled water had taste, color, and smell, respectively. However, 27.5%, 25.4%, and 34.5% of the respondents agreed that tap water had taste, color, and smell, respectively. Both tap and bottled water met the World Health Organization (WHO) guidelines for pH, total dissolved solids, chloride, copper, sodium, sulfate, and nitrate. However, a tap water sample was found to contain Coliform bacteria. In this line, affected communities need to thoroughly boil the raw tap water to kill the pathogens. All tap water samples yielded iron concentrations above the WHO recommended limit. Student's t-tests showed that tap and bottled water samples were significantly
different with respect to total dissolved solids, pH, chloride, calcium, magnesium, iron, sodium, sulfate, and nitrate. We emphasize the need for routine maintenance of the water distribution system to check for leakages which can be potential source of contaminations.
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Farjami A, Hatami MS, Siahi-Shadbad M, Lotfipour F. Peracetic acid Activity on Biofilm Formed by Escherichia coli Isolated from an Industrial Water System. Lett Appl Microbiol 2022; 74:613-621. [PMID: 34984695 DOI: 10.1111/lam.13647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 12/26/2021] [Accepted: 12/28/2021] [Indexed: 11/30/2022]
Abstract
One of the major problems in industrial water systems is the generation of biofilm, which is resistant to antimicrobial agents and causes failure of sanitization policy. This work aimed to study the anti-biofilm activity of peracetic acid (PAA) at contact times and temperatures combinations. To this end, a 96 well microtiter-based calorimetric method was applied in in vitro biofilm production using Ecsherichia coli, isolated from the water supply system of a pharmaceutical plant. The phenotypic and phylogenetic tests confirmed the isolated bacteria belong to strains of Ecsherichia coli. The anti-biofilm activity of peracetic acid on formed biofilm was investigated at concentrations of 0.15-0.5% for a contact time of 5-15 min at 20°C to 60°C. The maximum biofilm formation by MTP method using an Ecsherichia coli isolate was achieved in 96 h incubation in TSB containing wells at 37°C. Biofilm formation rate showed to be high by the environmental isolate compared with that of standard strain. PAA at concentrations above 0.25%, the temperature of 40°C, and a minimum of 10 minutes of contact time was effective in the eradication of biofilm in an MPT-based system.
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Affiliation(s)
- Afsaneh Farjami
- Food and Drug Safety Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Pharmaceutical Analysis Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Mohammadreza Siahi-Shadbad
- Food and Drug Safety Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Farzaneh Lotfipour
- Food and Drug Safety Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
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Photocatalytic Inactivation as a Method of Elimination of E. coli from Drinking Water. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11031313] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The presence of microorganisms, specifically the Escherichia coli, in drinking water is of global concern. This is mainly due to the health implications of these pathogens. Several conventional methods have been developed for their removal; however, this pathogen is still found in most drinking water. In the continuous quest for a more effective removal approach, photocatalysis has been considered as an alternative method for the elimination of pathogens including E. coli from water. Photocatalysis has many advantages compared to the conventional methods. It offers the advantage of non-toxicity and utilizes the energy from sunlight, thereby making it a completely green route. Since most photocatalysts could only be active in the ultraviolet region of the solar spectrum, which is less than 5% of the entire spectrum, the challenge associated with photocatalysis is the design of a system for the effective harvest and complete utilization of the solar energy for the photocatalytic process. In this review, different photocatalysts for effective inactivation of E. coli and the mechanism involved in the process were reviewed. Various strategies that have been adopted in order to modulate the band gap energy of these photocatalysts have been explored. In addition, different methods of estimating and detecting E. coli in drinking water were presented. Furthermore, different photocatalytic reactor designs for photocatalytic inactivation of E. coli were examined. Finally, the kinetics of E. coli inactivation was discussed.
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