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Bactericidal activity of electrolyzed acid water from solution containing sodium chloride at low concentration, in comparison with that at high concentration
Abstract
Electrolyzed strong acid water (ESW) containing free chlorine at various concentrations is becoming to be available in clinical settings as a disinfectant. ESW is prepared by electrolysis of a NaCl solution, and has a corrosive activity against medical instruments. Although lower concentrations of NaCl and free chlorine are desired to eliminate corrosion, the germicidal effect of ESW with low NaCl and free-chlorine concentrations (ESW-L) has not been fully clarified. In this study, we demonstrated that ESW-L possesses bactericidal activity against Mycobacteria and spores of Bacillus subtilis. The effect was slightly weaker than that of ESW containing higher NaCl and free-chlorine concentrations (ESW-H), but acceptable as a disinfectant. To clarify the mechanism of the bactericidal activity, we investigated ESW-L-treated Pseudomonas aeruginosa by transmission electron microscopy, a bacterial enzyme assay and restriction fragment length polymorphism pattern (RFLP) assay. Since the bacterium, whose growth was completely inhibited by ESW-L, revealed the inactivation of cytoplasmic enzyme, blebs and breaks in its outer membrane and remained complete RFLP of DNA, damage of the outer membrane and inactivation of cytoplasmic enzyme are the important determinants of the bactericidal activity.
... Klorin ini akan berinteraksi dengan enzim bakteri dan menghancurkan periplasma dan membran dalam sehingga sitoplasma dapat keluar dari sel bakteri yang berakibat kematian sel bakteri. 15,16 Dari 57 subyek penelitian didapatkan hasil kuman Gram negatif dengan persentase tertinggi (77,2%). Hal ini sesuai dengan acuan pustaka yang menyatakan bahwa kuman Gram negatif sering ditemukan pada keadaan infeksi berat yang disertai adanya jaringan nekrotik atau gangren. ...
... Kuman patogen terbanyak yang ditemukan pada ulkus diabetik ialah Proteus 20 Efektivitas PHMB pada penelitian ini sesuai dengan kajian kerja PHMB sebagai bakterisidal dengan sifat basanya berikatan dengan fosfat bermuatan negatif pada membran fosfolipid bakteri, menghancurkan membran luar dan dalam dari dinding sel bakteri melalui gangguan permeabilitas, dan mengeluarkan sitoplasma sel bakteri dengan cara osmosis. 13,14 Hasil uji statistik mendapatkan perbedaan tidak bermakna dari proporsi kepekaan terhadap NaCl 20% gel ( 15 yang menyimpulkan bahwa NaCl konsentrasi tinggi mempunyai efek bakterisidal yang baik dan dapat dijelaskan dengan mengkaji kembali sifat kerja NaCl dalam menghancurkan bakteri. Pada perbandingan efek bakterisidal antara NaCl konsentrasi rendah dan konsentrasi tinggi dijelaskan bahwa NaCl dalam bentuk cairan mempunyai sifat mendilusi dan menghancurkan membran luar dari bakteri 15,16 Pada penelitian ini, NaCl yang dipakai, meskipun mempunyai konsentrasi yang tinggi (20%), namun bentuk yang tersedia ialah gel sehingga mekanisme kerja NaCl dalam bentuk cair yang dapat mendilusi membran luar bakteri, tidak bisa dicapai dalam penelitian ini. ...
... 13,14 Hasil uji statistik mendapatkan perbedaan tidak bermakna dari proporsi kepekaan terhadap NaCl 20% gel ( 15 yang menyimpulkan bahwa NaCl konsentrasi tinggi mempunyai efek bakterisidal yang baik dan dapat dijelaskan dengan mengkaji kembali sifat kerja NaCl dalam menghancurkan bakteri. Pada perbandingan efek bakterisidal antara NaCl konsentrasi rendah dan konsentrasi tinggi dijelaskan bahwa NaCl dalam bentuk cairan mempunyai sifat mendilusi dan menghancurkan membran luar dari bakteri 15,16 Pada penelitian ini, NaCl yang dipakai, meskipun mempunyai konsentrasi yang tinggi (20%), namun bentuk yang tersedia ialah gel sehingga mekanisme kerja NaCl dalam bentuk cair yang dapat mendilusi membran luar bakteri, tidak bisa dicapai dalam penelitian ini. Klorin bebas, seperti HCLO, Cl 2 , dan Clyang merupakan hasil elektrolisis dari NaCl tidak bisa berinteraksi dengan enzim bakteri atau menghancurkan periplasma dan membran dalam sehingga sitoplasma tidak dapat keluar dari sel bakteri, dan tidak berakhir dengan kematian bakteri. ...
The prevalence of diabetes mellitus (DM) is increased globally every year, especially in developed countries. In Indonesia, the prevalence of diabetic ulcers is amounted to 15%. Mortality and amputation are as high as 32.5% and 23.5% and are the most common cause of diabetic patient care in the hospital. This study was aimed to compare the sensitivity of diabetic ulcers’ bacteria to PHMB gel with 0.9% saline gel. This was a descriptive analytical study. Subjects were 57 patients of diabetic ulcer associated with infection. Pus samples obtained from the diabetic ulcers were cultured and were further evaluated for the sensitivity test to PHMB gel and saline gel. Data were analyzed by using the ƻ test. The results showed that the proportion of bacteria’ sensitivity to PHMB was significantly different (P <0.05) meanwhile to 20% saline gel was not significantly different (P <0.05). Conclusion: Application of PHMB gel could improve the process of wound healing of diabetic ulcer with infection.Keywords: PHMB gel, Na Cl gel, diabetic ulcer with infectionAbstrak: Prevalensi penyandang diabetes melitus (DM) secara global semakin meningkat setiap tahunnya terutama di negara berkembang. Di Indonesia, prevalensi ulkus diabetik pada penyandang DM sebesar 15%. Angka kematian dan amputasi sangat tinggi yaitu sebesar 32,5% dan 23,5% yang merupakan penyebab terbanyak perawatan di rumah sakit. Penelitian ini bertujuan untuk mendapatkan pola kuman pada ulkus diabetik serta membandingkan kepekaan kuman terhadap PHMB gel dan NaCl gel. Jenis penelitian ialah deskriptif analitik. Subyek penelitian ialah 57 pasien dengan ulkus diabetik disertai infeksi. Sampel pus dari ulkus diabetik dibuat kultur kemudian dilanjutkan dengan uji kepekaan kuman terhadap PHMB gel dan NaCl gel. Data dianalisis menggunakan uji ƻ. Hasil uji statistik mendapatkan perbedaan proporsi kepekaan kuman terhadap PHMB yang bermakna (P < 0,05) sedangkan perbedaan proporsi kepekaan kuman terhadap NaCl gel 20% tidak bermakna (P >0,05). Simpulan: Pemberian PHMB gel dapat meningkatkan proses penyembuhan luka pada penyandang DM dengan ulkus yang disertai infeksi.Kata kunci: PHMB gel, Na Cl gel, ulkus diabetik dengan infeksi
... The electrolysis of diluted solution of salts (e.g., NaCl, KCl, and MgCl 2 ) leads to dissociation of salt ions, and formation of anion and cations at anode and cathode, negative and positive electrodes, respectively [94]. The physical properties and chemical composition of EW vary depending on the concentration of salt solution (e.g., NaCl), electrical current, length of electrolysis, and water flow rate [95]. Most previous studies assessed electrolyzing parameters (flow rate, current intensity, and time for electrolyzing) effect on free chlorine, electric conductivity, and pH of the resulted EW [96][97][98], while very few studied the effect of electrolyzing parameters on the ability of electrolyzed water to deactivate pathogen unit [17]. ...
... The role of pH is believed to make the cells more sensitive to active chlorine by erupting their outer membrane and facilitating the entry of HOCl [106]. Previous papers have studied the effect of electrolyzing parameters on the electrolyzed water characteristics [17,95]. Recently, acidic electrolyzed water has shown higher biocidal activity toward P. digitatum, P. italicum, and P. ulaiense causing green, blue, and whisker moulds, respectively. ...
... Since the anolyte has the non-destructive properties of other organic materials, it is not harmful and can be used in food sanitation. Anolyte is effective and harmless, not only for the disinfection of food contact surfaces but also for the treatment (washing and spraying) of the products (vegetables, fruits, seafood and meat products) [3][4][5][6]. ...
... The bactericidal effect, although greatly reduced, carries over to spores as well [9,10]. These findings were in line with research conducted by Kiura et al. [4] who found that electrolyzed strong acid water (ESW) created breaks and blebs in the cell membranes of Pseudomonas aeruginosa. These breaks, as well as the destruction of DNA, increased with growing concentrations of free chlorine concentrations. ...
In this paper, anolyte is considered as a possible disinfectant for inhibiting the growth of bacteria in meat (beef cuts and minced pork). Meat cuts were contaminated with two concentrations of L. monocytogenes and S. Typhimurium, as these are the most common meat pathogens that are closely regulated by the EU, and treated with two different concentrations of anolyte: 20% for beef cuts and 18% for minced pork. Then, the total viable count (TVC), L. monocytogenes count and S. Typhimurium count were determined. In meat cuts and minced pork, anolyte was able to reduce TVC, S. Typhimurium and L. monocytogenes counts effectively, significantly decreasing L. monocytogenes and S. Typhimurium counts after spraying and throughout 29 days of incubation at 0–4 °C. TVC was reduced after spraying and for 10 days of incubation but later increased to be the same as before spraying with anolyte. Anolyte was effective when spraying beef cuts with a 20% solution for 60 s against pathogenic bacteria L. monocytogenes and Salmonella spp. and also when using it at a concentration of 18% from the minced meat mass. Initially, anolyte significantly decreased TVC, however during the storage period (10–29 days) TVC increased but remained significantly lower compared to control. Anolyte was effective in reducing L. monocytogenes and S. Typhimurium counts throughout the study, and after 29 days of incubation, these bacteria could not be detected in the samples treated with anolyte.
... satisfactory increase in the pH range suitable for the generation of SAEW. Several authors have reported a linear correlation between the concentration of salt and the concentration of ACC generated by the electrolysis generator [24,92,96,97]. Kiura et al. [97] reported a strong correlation between the amount of salt, duration of electrolysis, and ACC production. ...
... Several authors have reported a linear correlation between the concentration of salt and the concentration of ACC generated by the electrolysis generator [24,92,96,97]. Kiura et al. [97] reported a strong correlation between the amount of salt, duration of electrolysis, and ACC production. A study by Ezeike and Hung [98] reported that a higher ORP and ACC of EW could be achieved with a higher salt concentration. ...
Currently, electrolyzed water, a sustainable and environmentally friendly disinfectant produced through electrolysis of an acid or salt, has become very popular because of its applications in various sectors such as health, agriculture, and food. Influencing factors are important for optimizing the electrolyzed water production process and maximizing application efficiency. Factors that influence the production and efficiency of electrolyzed water, including water and electrolyte properties, electrode material, current, storage, and application factors, were reviewed in this study. Moreover, some commercially available generator models, their specifications, and issues are discussed along with future recommendations. This work summarizes the available literature from January 2000 to December 2020, reporting studies that can assist in understanding various parameters affecting the production and stability of electrolyzed water. This can provide further insights and aid researchers in optimizing the process and address the issues faced by the existing systems by offering new perspectives in future studies.
... The current results indicated LcEW was pretty effective while at low concentrations as Kiura et al. (2002) demonstrated the germicidal effect on Mycobacteria and spores of Bacillus subtilis. The effect was only slightly weaker than that of 50 mg/L FAC EW. ...
... In addition, for the LcEW treated groups, the fluorescence intensity showed a declining trend with an increase in temperature. ROS such as ·OH − and O 3 have been reported as bactericidal agents in EW, which may inactivate bacteria by reducing activities of dehydrogenase and nitrate reductase (Kiura et al., 2002). In the present study, accounting for the results of fluorescence intensity for LcEW at different temperatures and the disinfection efficacy of the treatments, considering the extreme low chlorine concentration of EW, the accumulated ROS rather than the chlorine compounds might play a key role in the disinfection by LcEW. ...
In the present study, the synergistic disinfection efficacy of low concentration electrolyzed water (LcEW) (free available chlorine, 4mg/L) combined with brief heat enhancement was evaluated and the bactericidal mechanism was investigated by atomic force microscopy (AFM). The inactivation kinetics of Escherichia coli O157:H7 and Salmonella Typhimurium on organic carrot were fitted with Weibull model to evaluate the synergistic effects. LcEW is effective at inactivating E. coli O157:H7 and S. Typhimurium on organic carrots, and the efficacy is dependent on the temperature. The combined treatment with LcEW at 80°C resulted in decimal reductiontime(TR)of7.42and3.27sforE.coliO157:H7andS.Typhimurium,respectively.Thereactiveoxygen species generated from LcEW were responsible for the microbial inactivation. In addition, AFM observation of E. coli O157:H7 and S. Typhimurium revealed morphological alterations in the bacterial cell structure, which illustrated the damage of cell membrane injury and intracellular component leakage. Quality attributes of carrot treated with LcEW and short-time heating (70°C, 1min) were not significantly different from controls. Compared to the control group, the combined treatment exhibited significantly (P < 0.05) greater inhibition of naturally occurring microbiota on organic carrots during storage at 4°C. Consequently, the application of LcEW combined with short-time heat improved safety of organic carrot, without negatively affecting the sensory properties, which can be explored by the organic industry.
... Huang et al. (2006b) reported that EW containing 50 or 100 mg/L chlorine with CO gas treatment in tuna fish steak would be an effective method for enhancing the freshness quality for tuna meat and extending refrigerated storage time. EW was found to be especially effective in reducing population of E. coli and V. parahaemolyticus on tilapia (Huang et al. 2006a), as well as Pseudomonas aeruginosa (Kiura et al. 2002;Vorobjeva et al. 2004). Based on these positive bactericidal and preservative effects of EW, and its comparative safety to human health (Park et al. 2002a, b), EW is also thought be effective in suppressing spoilage bacteria in fresh fish in the distribution chain. ...
... EW has been reported to exhibit very strong bactericidal properties against many pathogenic bacteria including Pseudomonas aeruginosa (Kiura et al. 2002;Vorobjeva et al. 2004), Escherichia coli 0157:H7, Salmonella enteritidis, Listeria monocytogenes, Compylobacter jejuni, Enterobacter aerogenes and Staphylococcus aureus (Kim et al. 2000b;Park et al. 2002a, b;Venkitanarayanan et al. 1999). Many studies have demonstrated the potential use of EW as an effective disinfectant to reduce microbial contamination on vegetables (Izumi 1999;Koseki et al. 2001Koseki et al. , 2004; poultry (Fabrizio et al. 2002;Park et al. 2002a); cutting boards (Venkitanarayanan et al. 1999); seafood (Kim et al. 2006;Pudtikajorn et al. 2009); surface like glass, stainless steel, glazed and unglazed ceramic tiles and vitreous china (Park et al. 2002b). ...
The efficacy of electrolyzed water (EW) against surface bacteria for increased freshness of fish during distribution was investigated and its efficiency was compared with chlorinated water (CW) and some natural herbal extracts. Fresh oil sardine (Sardinella longiceps), Pacific mackerel (Scomber japonicas) and horse mackerel (Trachurus trachurus) were dipped into variable concentrations of EW, CW, EW-mix (EW + bamboo extract + garlic extract at 60:1:1), sterile distilled water, tap water, garlic extract and bamboo extract for 0, 1, 3, 5, 10, 15, 20, 25 and 30 min, respectively. Aerobic plate count (APC) was done, biochemical properties were studied and freshness of fish was measured using quality assessment tool. Iso-chlorine EW, CW and EW-mix were found to be effective in reducing APC at 25 °C. Fish treated with EW and CW showed better keeping quality in terms of bacterial load and physical properties of fish compared to other solutions. So, EW can be effectively used to reduce bacterial spoilage and extend shelf life of fish during distribution and marketing. Keywords Electrolyzed water · Chlorinated water · Bamboo and garlic extracts · Fish spoilage bacteria · Aerobic plate count · Shelf life of wet fish
... Huang et al. (2006b) reported that EW containing 50 or 100 mg/L chlorine with CO gas treatment in tuna fish steak would be an effective method for enhancing the freshness quality for tuna meat and extending refrigerated storage time. EW was found to be especially effective in reducing population of E. coli and V. parahaemolyticus on tilapia (Huang et al. 2006a), as well as Pseudomonas aeruginosa (Kiura et al. 2002;Vorobjeva et al. 2004). Based on these positive bactericidal and preservative effects of EW, and its comparative safety to human health (Park et al. 2002a, b), EW is also thought be effective in suppressing spoilage bacteria in fresh fish in the distribution chain. ...
... EW has been reported to exhibit very strong bactericidal properties against many pathogenic bacteria including Pseudomonas aeruginosa (Kiura et al. 2002;Vorobjeva et al. 2004), Escherichia coli 0157:H7, Salmonella enteritidis, Listeria monocytogenes, Compylobacter jejuni, Enterobacter aerogenes and Staphylococcus aureus (Kim et al. 2000b;Park et al. 2002a, b;Venkitanarayanan et al. 1999). Many studies have demonstrated the potential use of EW as an effective disinfectant to reduce microbial contamination on vegetables (Izumi 1999;Koseki et al. 2001Koseki et al. , 2004; poultry (Fabrizio et al. 2002;Park et al. 2002a); cutting boards (Venkitanarayanan et al. 1999); seafood (Kim et al. 2006;Pudtikajorn et al. 2009); surface like glass, stainless steel, glazed and unglazed ceramic tiles and vitreous china (Park et al. 2002b). ...
The efficacy of electrolyzed water (EW) against surface bacteria for increased freshness of fish during distribution was investigated and its efficiency was compared with chlorinated water (CW) and some natural herbal extracts. Fresh oil sardine (Sardinella longiceps), Pacific mackerel (Scomber japonicas) and horse mackerel (Trachurus trachurus) were dipped into variable concentrations of EW, CW, EW-mix (EW + bamboo extract + garlic extract at 60:1:1), sterile distilled water, tap water, garlic extract and bamboo extract for 0, 1, 3, 5, 10, 15, 20, 25 and 30 min, respectively. Aerobic plate count (APC) was done, biochemical properties were studied and freshness of fish was measured using quality assessment tool. Iso-chlorine EW, CW and EW-mix were found to be effective in reducing APC at 25 °C. Fish treated with EW and CW showed better keeping quality in terms of bacterial load and physical properties of fish compared to other solutions. So, EW can be effectively used to reduce bacterial spoilage and extend shelf life of fish during distribution and marketing.
... Conversely, the poor germicidal activity of the OCl − specie is because penetration of this ion is prevented by the hydrophobic layer of microbe's plasma membrane (Fukuzaki, 2006). Nan et al. (2010), Kim et al. (2019) and Kiura et al. (2002) analyzed the bacterial cellular morphology before and after treatment with solutions containing free chlorine by transmission electron microscopy. Nan et al. (2010) and Kim et al. (2019) found that E. coli cells were remarkably damaged, destroyed or deformed after exposure to SAEW with free chlorine concentrations between 10 and 60 mg/L. ...
... Nan et al. (2010) and Kim et al. (2019) found that E. coli cells were remarkably damaged, destroyed or deformed after exposure to SAEW with free chlorine concentrations between 10 and 60 mg/L. Kiura et al. (2002) observed damage of the outer membrane of P. aeruginosa and inactivation of cytoplasmic enzyme after exposure to free chlorine concentration solutions, which, according to this research team, are clear indicators of the bactericidal activity of free chlorine solutions. The bactericidal effect of SAEW lies in the synergy between high oxidation-reduction potential (ORP, equal to or greater than 900 mV) and HOCl. ...
Bacterial inactivation is a crucial aspect of sanitation and hygiene. The effectiveness of slightly acidic electrolyzed water (SAEW) for reduction or removal of Escherichia coli , Pseudomonas aeruginosa and Staphylococcus epidermidis was evaluated. The bactericidal activity of SAEW and sodium hypochlorite (NaOCl) against E. coli and P. aeruginosa were compared through in vitro experiments. The effectiveness of SAEW spray was tested against S. epidermidis . Results showed that SAEW had a more powerful bactericidal activity than NaOCl at the same available chlorine concentrations. For E. coli , SAEW decreased the bacterial counts from 8.4 log 10 CFU/mL to less than 3.9 log 10 CFU/mL; NaOCl with the same available chlorine of 0.5 mg/L, caused a decrease from 8.4 log 10 CFU/mL to 7.1 log 10 CFU/mL. For P. aeruginosa , SAEW caused bacterial counts to decrease from 8.5 log 10 CFU/mL to less than 4.1 log 10 CFU/mL against 8.5 log 10 CFU/mL to 6.2 log 10 CFU/mL for NaOCl with the same available chlorine of 0.5 mg/L. Spray experiments showed that 10 mg/L of SAEW spray decreased the bacterial counts of S. epidermidis from 3.7 log 10 CFU/m ³ to 2.8 log 10 CFU/m ³ , with 20 mg/L causing a reduction from 3.8 log 10 CFU/m ³ to 0 CFU/m ³ . The overall findings of this study indicate that SAEW may be a promising disinfectant agent either as a solution or spray.
... The alkaline solution from the cathode has a high pH and low ORP (Kumon, 1997). The physical properties and chemical composition of EOW varies dependent on concentration of NaCl, amperage level, time of electrolysis or water flow rate (Kiura et al., 2002;Hsu S. Y., 2003;Nakajima et al., 2004). ...
... Thus, the large amount of HOCl on account of the low pH of ~3 is considered the chief factor of the disinfecting efficacy of EO water (Vorobjeva et al., 2004;White, 1999). Due to the water-like structure, the low molecular weight, and the electrical neutrality, HOCl molecules can easily diffuse through the bacterial cell wall into the cytoplasm (Kiura et al., 2002;Len et al., 2000;White, 1999). The bactericidal mechanism is probably the irreversible oxidation of cytoplasmic enzymes in particular in the inner membrane and peripheral cytoplasm (Matsunaga et al., 1984). ...
... The active chlorine species in SAEW, including HOCl, Cl 2 , and OCl-, play a significant role in the inactivation of microorganisms. Generally it was reported that active chlorine can destroy membranes of the microorganisms, decarboxylate the amino acids, inhibit oxygen uptake and oxidative phosphorylation coupled with leakage of some macromolecules, inhibit glucose oxidation by chlorine-oxidizing sulfhydryl groups, form toxic N-chlorine derivatives of cytosine, disrupt protein synthesis, react with nucleic acids, purines, and pyrimidines, and unbalance metabolism of key enzymes [30,38,52]. The antimicrobial effect of SAEW mainly caused by the presence of HOCl has been extensively studied and proved [56,61]. ...
Slightly acidic electrolyzed water (SAEW) obtained by electrolyzing 2-6% dilute hydrochloric acid in a chamber without membrane is novel non-thermal sanitizer widely used in the sterilization of foods such as fruits, vegetables, and meat owing to its effective antibacterial activity and low operating costs. Despite the well-documented and validated antimicrobial and sporicidal properties of SAEW, its precise mode of action against bacteria and bacterial spores remains uncertain and subject to ongoing debate. The primary aim of this review article is to scrutinise the active constituents of SAEW that contribute to its antimicrobial properties. Additionally, the review critically elucidates the mechanisms by which SAEW effectively inactivate vegetative bacteria cells and spores, based on a comprehensive scrutiny of existing literature. It is demonstrated that the application of SAEW can kill vegetative bacterial cells by the disruption of their cellular membrane, disruption of their intracellular reactive oxygen species (ROS) balance, and lowering their ATP levels, deactivation of key enzyme and damaging DNA affecting other bacterial cells vitals. Bacterial spore inactivation by SAEW being achieved through the induction of structural modifications in the spores, including coat damage, mutagenesis, and alterations in the properties of the inner membrane (IM).
... Cl-free anions produced by the electrical dissociation of the Cl salt, a fortified NaCl salt for ROX electrolysis machine, are powerful oxidants that intervene in several biological structures and functions [38], [39], [40]. Also, the treatments by alkaline (alEW) and acidic (acEW) electrolyzed water caused irregular mycelia growth, irregular branching of hyphae in the apical part and loss of linearity in the tested fungal structures, the results showed by scanning electron microscopy (SEM). ...
... FAC is widely believed to achieve disinfection via disrupting the osmotic homeostasis within the bacterial cells whereas other findings indicate that disruption of membrane structure is also responsible for its wide-spectrum antimicrobial effects (Deza et al., 2003;Issa-Zacharia et al., 2010;Kiura et al., 2002;Wu et al., 2021). To explore the antimicrobial mechanisms of the chlorine-based sanitisers on the "big six" E. coli strains, metabolic alterations within the E. coli cells induced by the treatments must be investigated. ...
Sodium chlorite (NaClO), the most commonly used sanitiser for fresh produce decontamination, is associated with the problems of pungency and corrosiveness. In search for a more environmentally- and user-friendly chlorine-based sanitiser, acidic electrolysed water (AEW), came into view in recent years. To determine whether AEW is an ideal alternative to NaClO, using ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS), this study thoroughly investigated the effectiveness of AEW and NaClO, both containing 4 mg/L of free available chlorine (FAC), in inhibiting the “big six” Escherichia coli pathogens (serotypes O26, O45, O103, O111, O121 and O145) on lettuce as well as the underlying antimicrobial mechanisms. The two sanitisers led to generally comparable E. coli cell reductions after a 10-min treatment, which indicated the decisive role of FAC in their antimicrobial effects. Among the strains, mortalities varied from approximately 0.68 log CFU/g in O111 under both treatments to 1.48 ± 0.04 log CFU/g in AEW-treated O26 and 1.23 ± 0.04
log CFU/g in NaClO-treated O45. O111’s high resistance was confirmed by its almost undisturbed metabolome whereas the high lethality of O26 and O45 could be attributed to the loss of membrane phospholipids. Besides, retarded cell growth and energy deficiency as implied by a vast depletion of nucleotide derivatives further challenged O45’s survival. Overall, the comparable sanitising efficacy and the similarity in antimicrobial
mechanisms between the two sanitisers provided a scientific basis for replacing NaClO with the “greener” AEW for fresh produce sanitisation in the future.
... Besides, the increased amino acids may also play a pivotal role in osmotic regulation of the VBNC cells. According to previous studies, osmotic stress is a secondary stress induced by chlorine treatment (Bridges, Lacombe, & Wu, 2022;Kiura et al., 2002;Q. Liu et al., 2017). ...
Facing the increasing occurrence of “big six” Escherichia coli outbreaks linked to fresh produce, chlorine-based sanitisers are widely used for fresh produce decontamination in recent years. However, latest finding that chlorine may induce E. coli cells into a viable not nonculturable (VBNC) state is bringing a new challenge to the fresh produce industry. VBNC cells are undetectable by the plate count test, and yet they retain pathogenicity and are more antibiotic-resistant than culturable cells. As a result, their eradication is critical to ensure the safety of fresh produce. Understanding VBNC cells at the metabolic level may provide a breakthrough for their eradication. Therefore, this study was carried out to collect the VBNC pathogenic E. coli (O26:H11, O121:H19, and O157:H7) cells from chlorine-treated pea sprouts and characterise them using NMR-based metabolomics. From the globally increased metabolite contents detected in the VBNC E. coli cells as compared to the culturable cells, mechanisms underlying E. coli’s VBNC induction were elucidated. These include rendering the energy generation scheme to become more compatible with the lowered energy needs, disaggregating protein aggregates to release amino acids for osmoprotection and later resuscitation, as well as increasing cAMP content to downregulate RpoS. These identified metabolic characteristics can inspire future development of targeted measures for VBNC E. coli cell inhibition. Our methods can also be applied to other pathogens to help lower the risk of overall foodborne diseases.
... At the anode, chloride ions are converted into gaseous chlorine, which then reacts with water to form hypochlorous acid, which plays a major role in disinfection, and results in the formation of EAW at pH 2.7. EAW has a broad antibacterial spectrum and has been shown to remove spore-forming bacteria [13], acid-fast bacteria [14,15], fungi [16,17], and blood-borne infection-causing viruses such as hepatitis B virus [18,19], and human immunodeficiency virus [20]. EAW has also been experimentally proven to be minimally cytotoxic [16]. ...
Glutaraldehyde, a germicide for reprocessing endoscopes that is important for hygiene in the clinic, might be hazardous to humans. Electrolyzed acid water (EAW) has a broad anti-microbial spectrum and safety profile and might be a glutaraldehyde alternative. We sought to assess EAW disinfection of flexible endoscopes in clinical otorhinolaryngological settings and its in vitro inactivation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and bacteria commonly isolated in otorhinolaryngology. Ninety endoscopes were tested for bacterial contamination before and after endoscope disinfection with EAW. The species and strains of bacteria were studied. The in vitro inactivation of bacteria and SARS-CoV-2 by EAW was investigated to determine the efficacy of endoscope disinfection. More than 20 colony-forming units of bacteria at one or more sampling sites were detected in 75/90 microbiological cultures of samples from clinically used endoscopes (83.3%). The most common genus detected was Staphylococcus followed by Cutibacterium and Corynebacterium at all sites including the ears, noses, and throats. In the in vitro study, more than 10 ⁷ CFU/mL of all bacterial species examined were reduced to below the detection limit (<10 CFU/mL) within 30 s after contact with EAW. When SARS-CoV-2 was treated with a 99-fold volume of EAW, the initial viral titer (> 10 ⁵ PFU) was decreased to less than 5 PFU. Effective inactivation of SARS-CoV-2 was also observed with a 19:1 ratio of EAW to the virus. EAW effectively reprocessed flexible endoscopes contributing to infection control in medical institutions in the era of the coronavirus disease 2019 pandemic.
... Strongly acidic EW and free chlorine content may be corrosive to some metals and may induce synthetic resin degradation (Tanaka et al. 1999), and hazardous chlorinated by-products can be produced. Its effectiveness may be hindered by the presence of organic substances (Oomori et al. 2000); its antimicrobial potential could be loosed quickly, once the apparatus is switched-off (Kiura et al. 2002). Depending on the electrolyte used and the pH (e.g. in AEW), pungent chlorine gas is formed that can cause discomfort to operators (Al-Haq et al. 2005). ...
The control of plant diseases is still widely carried out through the use of synthetic chemicals. However, many fungal and bacterial pathogens have developed resistance to the active ingredients of a wide range of pesticides. In addition, the problems associated with their use (i.e., waste disposal) as well as the increasing public awareness regarding residues and environmental risks have promoted the search for new and safer alternatives. Thus, the replacement of chemical pesticides with non-toxic compounds for consumers and for the environment is gaining considerable attention worldwide. Lowering the loss of products can be achieved through the use of an integrated disease management program, which employs a variety of control means and methods with a focus on preventing, reducing, and eradicating predisposing/instigating factors.
In this Special Issue, we invite scientists and researchers to contribute research articles on the utilization of a range of alternative control strategies, such as biological control using antagonistic/beneficial agents; physical strategies using low temperatures, modified and controlled atmospheres, heat, and irradiation; and substances generally regarded as safe, such as sanitizers, plant extracts, and essential oils. Papers that concentrate on the integrated disease management of agricultural products are also accepted.
In this Special Issue, original research articles and reviews are welcome. Research areas may include (but are not limited to) the following:
Integrated strategies to control plant diseases;
Alternatives to reducing/substituting chemical pesticides;
Natural compounds to control plant diseases;
Physical means of managing plant pathogens/diseases;
The role of biocontrol agents in managing plant diseases;
Nanotechnology as a way to control plant diseases.
We look forward to receiving your contributions.
Prof. Dr. Youssef Khamis
Prof. Dr. Antonio Ippolito
Prof. Dr. Khaled A. El-Tarabily
Guest Editors
... High ORP will affect the metabolic compounds in bacterial cells and lead to cell death. OH − and H2O2 can damage cell lipid membranes, denature proteins and prevent them from reproducing, destroying bacteria by cutting DNA to prevent enzyme activation [38,39]. At present, the sterilization of EW has not been fully elucidated, but a model to explain the sterilization mechanism of EW has been roughly developed. ...
Electrolyzed water (EW) is a new type of cleaning and disinfecting agent obtained by means of electrolysis with a dilute sodium chloride solution. It has low cost and harm to the human body and is also friendly to the environment. The anode produces acidic electrolyzed water (AEW), which is mainly used to inhibit bacterial growth and disinfect. The cathode provides basic electro-lyzed water (BEW), which is implemented to promote human health. EW is a powerful multifunc-tional antibacterial agent with a wide range of applications in the medicine, agriculture, and food industry. Studies in vitro and in vivo show that it has an inhibitory effect on pathogenic bacteria and viruses. Therefore, EW is used to prevent chronic diseases, while it has been found to be effective against various kinds of infectious viruses. Animal experiments and clinical trials clearly showed that it accelerates wound healing, and has positive effects in oral health care, anti-obesity, lowering blood sugar, anti-cancer and anti-infectious viral diseases. This review article summarizes the application of EW in treating bacteria and viruses, the prevention of chronic diseases, and health promotion.
... It is believed that HOCl's germicidal activity is due to its ability to penetrate the microbial cell wall and plasma membrane, causing damage to the DNA and also inhibiting enzyme activity essential for growth [18]. Kiura et al. [19], Nan et al. [20], Ding et al. [21] and Kim et al. [22] reported on the bacterial cellular morphology before and after treatment with solutions containing free chlorine by transmission electron microscopy. They concluded that bacterial cells were damaged, destroyed or deformed due to exposure to SAEW with free chlorine concentrations between 10 to 60 mg/L. ...
(1) Background: Slightly acidic electrolyzed water (SAEW) is an effective and safe sterilizing solution. Its active component is hypochlorous acid (HOCl) which has been proved to exhibit a strong disinfectant activity. In this research we evaluated the effectiveness of SAEW in the removal of Methylobacterium mesophilicum, Rhodotorula mucilaginosa and Cladosporium cladosporioides, responsible for pink-colored biofilm and black mold in households. (2) Methods: Two concentrations of SAEW, 20 mg/L and 40 mg/L, were tested against M. mesophilicum, R. mucilaginosa and C. cladosporioides. In vitro experiments and mesh experiments were conducted to test the effectiveness of SAEW. (3) Results: The test results showed that 40 mg/L SAEW was effective in removing R. mucilaginosa and C. cladosporioides, with the population decreasing by approximately two orders of magnitude. For M. mesophilicum, resistance towards SAEW was observed; to obtain a 1.3 order of magnitude decrease in bacterial population, washing 5 times with 40 mg/L SAEW was necessary. Mesh experiments showed that SAEW can remove black mold; (4) Conclusions: Overall results indicated that SAEW was particularly effective for R. mucilaginosa and C. cladosporioides species commonly found in Japanese households.
... The antimicrobial activity of EW has been widely demonstrated against various foodborne microorganisms, such as Pseudomonas aeruginosa [89,90], S. aureus [90], E. coli O157: H7 [91], S. Typhimurium [92], L. monocytogenes [91,93], C. jejuni [93] and V. parahaemolyticus [94]. It is also effective against spores, fungi and viruses present in food, environment and food processing plants. ...
Fish products are highly perishable, requiring proper processing to maintain their quality and safety during the entire storage. Different from traditional methods used to extend the shelf-life of these products (smoking, salting, marinating, icing, chilling, freezing, drying, boiling, steaming, etc.), in recent years, some alternative methods have been proposed as innovative processing technologies able to guarantee the extension of their shelf-life while minimally affecting their organoleptic properties. The present review aims to describe the primary mechanisms of some of these innovative methods applied to preserve quality and safety of fish products; namely, non-thermal atmospheric plasma (NTAP), pulsed electric fields (PEF), pulsed light (PL), ultrasounds (US) and electrolyzed water (EW) are analysed, focusing on the main results of the studies published over the last 10 years. The limits and the benefits of each method are addressed in order to provide a global overview about these promising emerging technologies and to facilitate their greater use at industrial level. In general, all the innovative methods analysed in this review have shown a good effectiveness to control microbial growth in fish products maintaining their organoleptic, nutritional and sensory characteristics. Most of the technologies have also shown the great advantage to have a lower energy consumption and shorter production times. In contrast, not all the methods are in the same development stage; thus, we suggest further investigations to develop one (or more) hurdle-like non-thermal method able to meet both food production requirements and the modern consumers’ demand.
... Being involved in bilayer formation and membrane protein folding, phosphorylcholine is crucially responsible for maintaining cell membrane integrity (Bogdanov et al., 1999;Sohlenkamp et al., 2003); its depletion, thus, indicated a weakened membrane structure of specific E. coli strains. Such membrane damage could be a joint consequence of the FAC and the high ORP within LcEW; FAC was found to exert its effect by eliciting blebs and breaks in the outer membrane of bacteria (Kiura et al., 2002), while a high ORP further enhances the permeability of the outer and inner cell membranes by oxidation so as to penetrate the protective sphere of bacteria (Liao et al., 2007). In a previous study based on atomic force microscopy (AFM), morphological changes of E. coli cells, including traumas on the membrane structure and roughened membrane surface, were observed after the LcEW treatment (Liu, Wu, et al., 2017), which ulteriorly evidenced the destruction of LcEW on E. coli membranes. ...
The antimicrobial effects of low concentration electrolysed water (LcEW) on common foodborne pathogens have been well documented; however, the effects on six emerging Escherichia coli serotypes (the “big six”) remained unknown. Using pea sprouts as the food matrix, this in vivo study examined the sanitising efficacy of a 10-min LcEW treatment against eight E. coli strains (non-pathogenic E. coli ATCC 25922, pathogenic E. coli O26:H11, O45:H2, O103:H11, O111, O121:H19, O145 and O157:H7). The metabolic responses of the strains were further analysed using nuclear magnetic resonance (NMR) spectroscopy. An overall negative correlation between the resistance to LcEW and the magnitude of metabolic variation was observed. The metabolic status and pathways of the most resistant O103:H11 and O45:H2 strains were the least affected. The O26:H11 and O145 strains which demonstrated the highest sensitivity to LcEW had an array of metabolites depleted and had multiple pathways involved in amino acid metabolism, energy metabolism as well as osmotic and oxidative protection perturbed. Distinctive metabolic responses were detected in ATCC 25922, suggesting that alternative stress defence mechanisms may be present in the non-pathogenic E. coli strain. Amongst the pathogenic strains, the most unique metabolic responses were illustrated by O121:H19. Overall, the study showed that the NMR-based metabolomics is promising in elucidating the metabolic changes of various E. coli strains in pea sprouts during an antimicrobial process. It also provides clue for controlling “big six” contamination in fresh produce.
... High ORP in electrolyzed water can cause modification of metabolic fluxes and ATP production due to electron flow change in cell. Active chlorine can disrupt membrane of microbes, inhibit oxygen uptake, decarboxylate the amino acids, disrupt protein synthesis, and unbalance metabolism of key enzymes (Kiura et al., 2002;Hricova et al., 2008). ...
The horticultural commodities, especially fruits and vegetables, form an indispensable component of our human diet as they contribute the essential nutrients required for crucial metabolic activities. Most of the fresh fruits and vegetables are consumed either in raw form or minimally processed form, rendering them susceptible to microbial contaminations, which may result in the outbreak of foodborne illness. Hence, a better understanding is required regarding the microbial flora inhabiting/affecting the fresh produce and the counter approaches for decontamination of the fresh fruits and vegetables before consumption. Several microorganisms have been identified to contribute for pre- and postharvest infections of the fresh produce. Hence, various postharvest decontamination technologies have been developed by food technologists over time to avoid/reduce the incidence of microbial loads over the fresh produce. Washing is the basic postharvest practice performed to reduce the filed microbial load; however, washing with normal water results in faster deterioration of the fresh produce. Hence, various new sanitizers have been innovated worldwide for reducing the levels of microbial loads responsible for postharvest hazards as well as foodborne illnesses. Some of the potential decontamination techniques such as chlorination, ozonation, pulsed light, irradiation, plasma technology, organic acids, hydrogen peroxide, electrolyzed water, and natural antimicrobial agents have been developed by the researchers. Research findings have indicated that the developed technologies had varying antimicrobial efficacy comparable to chlorine and the microbial reductions achieved through different methods are limited, raising food safety concerns. Also, there are limited considerations given to industrial applicability of the developed decontamination technologies.
... Strongly acidic EW and free chlorine content may be corrosive to some metals and may induce synthetic resin degradation (Tanaka et al. 1999), and hazardous chlorinated by-products can be produced. Its effectiveness may be hindered by the presence of organic substances (Oomori et al. 2000); its antimicrobial potential could be loosed quickly, once the apparatus is switched-off (Kiura et al. 2002). Depending on the electrolyte used and the pH (e.g. in AEW), pungent chlorine gas is formed that can cause discomfort to operators (Al-Haq et al. 2005). ...
Disinfection after harvest is an essential step to maintain commodities and facilities free of fungal and bacterial postharvest pathogens, responsible of storage decay and economic losses. Electrolyzed water (EW) has gained considerable interest over the last decades as a novel broad-spectrum sanitizer. EW is sustainable and cost effective since it can be produced on-site utilizing tap water and different inexpensive salts and is healthy for both the environment and human beings. Its effectiveness in controlling fungi, yeasts, and bacteria within a wide range of pH is due to multiple mode of actions. Furthermore, its strong oxidizing potential is capable to reduce the amount of pesticide residues on fruit and vegetable surfaces and to avoid pathogen resistance. Properties of EW are related to salts employed for production, being those with low chlorine content preferable. Lastly, EW has no negative effect on the organoleptic properties and features of treated commodities. The present chapter highlights recent developments in EW generation, factors affecting its effectiveness for controlling postharvest decay of fruits and vegetables, mechanism of action on microbes and hosts, and advantages and disadvantages on its use.
... The main disadvantage of these types of EW is that solutions tend to lose their antimicrobial activity because the compounds generated by electrolysis are either too volatile or dissipate very rapidly. 29 Still, our growth curves show that the compounds in EW eliminated the cells as soon as they entered in contact with them. In other words, even with the probable decrease in action over time, there are no longer any viable X. citri cells in the culture medium beyond the first minutes of treatment. ...
BACKGROUND
The largest and most profitable market for citrus is the production of fresh fruit. Xanthomonas citri subsp. citri is a Gram‐negative plant pathogen and the etiological agent of citrus canker, one of the major threats to citrus production worldwide. In the early stages of infection, X. citri can attach to plant surfaces by means of biofilms. Biofilm is considered an essential virulence factor, which helps tissue colonization in plants. Thus, sanitization of citrus fruit is mandatory in packinghouses before any logistic operation as packing and shipment to the market. The aim of this study was to evaluate electrolysed water (EW) as a sanitizer for the disinfection of citrus fruit in packinghouses.
RESULTS
Using a protocol to monitor cell respiration we show that EW, obtained after 8 and 9 min of electrolysis, sufficed to kill X. citri when applied at a concentration of 500 μL mL⁻¹. Furthermore, microscopy analysis, combined with time‐response growth curves, confirmed that EW affects the bacterial cytoplasmatic membrane and it leads to cell death in the first few minutes of contact. Pathogenicity tests using limes to simulate packinghouse treatment showed that EW, produced with 9 min of electrolysis, was a very effective sanitizer capable of eliminating X. citri from contaminated fruit.
CONCLUSION
It was possible to conclude that EW is significantly effective as sodium hypochlorite (NaClO) at 200 ppm. Therefore, EW could be an alternative for citrus sanitization in packinghouses. © 2020 Society of Chemical Industry
... The dilution of 10 -6 was too large which resulted in just a few numbers of countable colonies (less than ten). Therefore, the issues of discussion in this paper are only the results obtained from the milk dilutions 10 -4 and 10 - , [17] reported that the EO water with a lower concentration of NaCl (0.05%) has a lower bactericidal activity against Mycobacteria and spores of Bacillus subtilis in comparison to EO water with a higher concentration (0.3%), and it is still an effective disinfectant agent. The advantage of the EO with a lower concentration of NaCl is that it has less corrosive properties to the equipment being disinfected. ...
Consumers' growing demands for safe, minimally processed , fresh-like food as well as the disadvantages of traditional methods of microbial decontamination have led to the necessity of introducing innovative technologies for effective decontamination of food. In that way, a possible solution could be disinfectants based on elec-trolyzed oxidizing (EO) water, which are user-and environmentally friendly , with a convenient price. However, some milk producers and processors consider that disinfectants based on EO water are not effective enough in reducing the number of microorganisms on surfaces of equipment and utensils, in comparison to the other disinfectants which require rinsing. Therefore, the aim of this study was to investigate the efficacy of EO water as a disinfectant in the dairy industry. A commercial disinfectant based on EO water was used, and as a material for disinfecting milk sample with a known initial number of microorganisms. Disinfectant, taken from the original factory-sealed bottles, was diluted with double-distilled water in the three ratios, 1 : 10, 1 : 20 and 1 : 30. In the previously prepared dilutions of milk (10-1-10-6), control agents (double-distilled water and 0.1% NaCl solution) and three dilutions of disinfectant were added in the three ratios: 1 : 1, 1 : 10; 1 : 100. After incubation, the number of colonies of aerobic me-sophilic bacteria was counted (cfu/mL) and the analysis of variance of its logarithmic values was performed. It is found that disinfection done by the agent based on EO water is an effective method for microbial decontamina-tion in milk samples. The significant decrease (P < 0.05) of the number of aerobic mesophilic bacteria was observed in the cases of disinfectant's stronger concentration (1 : 10). Weaker concentration of disinfectant (1 : 20 and 1 : 30) showed less antibacterial activity, and in that case it is necessary to carry out rinsing of the equipment before using disinfectant, to remove organic milk matter which decreases the disinfection effect of free chlorine. The results confirmed that EO disinfectant is acceptable and sufficiently effective in the dairy industry, but it is recommended to use higher concentration, especially if traces of organic compounds retain on the treated surface.
... Even this S can not be generated into effective sanitizing components. Although the effectiveness of electrolyzed water has been widely documented in the literature (Abadias et al., 2008;Ayebah et al., 2005;Ayebah et al., 2006;Deza et al., 2003Deza et al., , 2005Deza et al., , 2007Guentzel et al., 2008;Issa-Zacharia, Kamitani, Morita, & Iwasaki, 2010;Kim et al., 2003;Kiura et al., 2002;Koseki & Itoh, 2000;Liao, Chen, & Xiao, 2007;Liu, Duan, & Su, 2006;Oomori, Oka, Inuta, & Arata, 2000;Yang, Swem, & Li, 2003), these waters were generated by relatively large equipment with high power, and had been electrolyzed sufficiently, thus can have sufficient sanitizing effects. One possible reason could be that the electrical power delivered by I was not sufficient to cause electrolysis. ...
Electrochemically activated water (ECAW), also known as electrolyzed water, and ozonized water are typically effective in inactivating bacteria, but their generation typically uses high current and voltage. A few simpler antimicrobial technologies that are also based on the application of a mild electrical current have been recently marketed to food retail and service customers claiming to have sanitizing properties for controlling bacteria. The objective of this study was to determine the sanitizing effect of some of these commercial technologies on Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica and compare them with sterile water, generated ECAW generated with a pilot size electrolyzing unit, and salt solutions sprayed using commercial device sprays. A concentration of 100 mg/L ECAW had sanitizing effects of at least 5 log CFU/mL reductions on liquid culture and more than 4 log CFU/coupon reductions for E. coli O157:H7, L. monocytogenes and Salmonella dried on stainless steel surface, respectively. No bacterial cells were detected by direct plate counting post-ECAW treatment. In contrast, the treatment of liquid cultures with any of the commercial technologies tested resulted in non-significant bacterial cell reductions greater than 0.5 log CFU/mL. Similarly, when cells had been dried on metal surfaces and treated with any of the water generated with those technologies, no reductions were observed. When the manufacturer's instructions were followed, the reduction of cells on surface was largely due to the physical removal by cloth-wiping after water fraction application. These results indicate that treatment with any of these portable technologies had no noticeable antimicrobial activity. These results would be helpful for guiding consumers when choosing a right sanitization to ensure food safety.
... Therefore, the values of TC, ORP and pH should be monitored and controlled during and after the electrolysis. the total chlorine due to the formation of oxidizing agents (ClO-and Cl 2 ) in reactions (2) and (3) 14,15,16 . The TC increased gradually with electrolysis time and was proportional to NaCl concentration (Fig. 4). ...
This study evaluated physicochemical and antibacterial properties of neutral electrolyzed water (NEW) produced by electrolyzing NaCl solutions. pH, total chlorine content (TC) and oxidation reduction potential (ORP) of NEW increased to equilibrium values when increasing NaCl concentration (0.20% - 1.5%) and electrolysis time (0 – 240 minute). The pH and ORP values increased sharply in the first 15-min of the electrolysis and then was stabilized in the ranges of 8.5-9.5 and 400-500 mV, respectively. Increasing NaCl concentration did not change the stabilized values of pH and ORP, but significantly increased (p<0.05) TC. Furthermore, we studied antibacterial activity of NEW against Escherichia coli and Salmonella enterica in suspension and in ground pork. Interestingly, 085% NaCl NEW after 10-min electrolysis reduced 7 log CFU/mL of E. coli and 2 log CFU/mL of S. enterica. This resistance of S. enterica toward NEW was possibly due to its biofilm-forming ability.
Pdf available at: http://www.orientjchem.org/vol36no3/physicochemical-properties-and-bactericidal-effects-of-neutral-electrolyzed-water-against-escherichia-coli-and-salmonella-enterica-on-ground-pork/
... The principles of electrolyzed water generation are based on electrolysis of a diluted solution of salts (e.g., NaCl, KCl, MgCl 2 ), which leads to dissociation of salt ions and formation of anions and cations at anode and cathode, negative and positive electrodes, respectively (Al-Haq et al. 2005). The physical properties and chemical composition of electrolyzed water vary with the concentration of salt solution, electrical current, length of electrolysis and water flow rate (Kiura et al. 2002). Most previous studies have assessed the effect of electrolyzing parameters (flow rate, current intensity, and time for electrolysis) on free chlorine, electric conductivity, and pH of the resulting electrolyzed water (Hsu 2003, Abbasi and Lazarovits 2006, Guentzel et al. 2010, Hussien et al. 2017, while very few researchers have studied the effect of electrolyzing parameters on the ability of electrolyzed water to suppress pathogen unit (Fallanaj et al. 2015). ...
... It is demonstrated that EW water was able to cause log reduction of of E.coli O157:H7 and L. monocytogenes in wide range of pH (2.6-7) if sufficient ACC present [89]. Also, concentration of free chlorine increases with the increase electrolysis time and concentration of NaCl in electrolysis [90]. ...
Uncontrolled growth of microorganism in foodstuff pose a severe challenge to the food industry, as it could leads to food spoilage, or even foodborne disease if the microorganism is pathogenic. To deal with these threats, sanitizers has been widely applied widely by food industry. In the last two decades, electrolyzed water (EW) has been food to be a promising new sanitizer for food industry, as it is more environmentally friendly compared to conventional chlorine-based disinfectants. This paper reviews the recent progress on the application of EW as a food sanitizer. EW was produced by the electrolysis of diluted NaCl (or HCl) solution and could be classified into several subgroups (acid EW, slightly EW, neutral EW, alkaline EW, low concentration) based on their pH and available chlorine concentration. The efficacy of using EW to inhibit the growth of several most important microorganism of food safety concern were proven by numerous studies. Besides, the application of EW has been seldomly associated with detrimental effects on the nutritional and sensory proprieties of food. However, its antimicrobial potency was affected by factors such as pH, temperature, storage time, and organic matter.
... For this reason, salt is used for disinfecting. (21,22) The results showed that there is a significant difference between saturated salt solution and distilled water as Protefix and Sodium hypochlorite 0.02%, therefore, it is considered as effective method in disinfection of denture contaminated with Candida species, this agrees with Al-Sumaidae. (19) This study showed that disinfection of the denture is a successful method of treatment, and the denture is the source of the infection and no other treatment necessary, and this agrees with Webb et al. (16) ...
Aim: The aim of the study is to evaluate the efficacy of three dentures cleanser on Candida related denture stomatitis through assessing their ability to reduce the number of colony forming unit (CFU) of Candida on palate of the patient for different times. Materials and methods: Group of 12 patients who have denture stomatitis were divided into four groups according to the type of denture cleaners (Protefix, sodium hypochlorite solution 0.02%, saturated sodium chloride salt solution and control wa-ter). The microbiological examination was done to determine the efficacy of the cleansers that used by assessing the number of (CFU) at different times (day before treatment and after 14, 28days of treat-ment). The data were statistically analyzed, (ANOVA) followed by Duncan's multiple Range test to assess the significant difference between the groups at P≤0.05. Results: The results showed that there was a significant effect of three cleansers on reducing number of (CFU) of Candida species in the treatment of denture stomatitis after 14 and 28 days of treatment, but it was not significant for control water group. Sodium hypochlorite showed the highest efficacy. Conclusions: Result showed that there was no significant difference in the efficacy between the three cleansers indicating that all cleansers are effective in the treatment of denture stomatitis .
... Electrolyzed oxidizing water. EOW has been reported to be an efficient antimicrobial agent for most foodborne pathogens (Bari, Sabina, Isobe, Uemura, & Isshiki, 2003;Kiura et al., 2002;C.M. Park, Hung, Doyle, Ezeike, & Kim, 2001). Most publications associate the antimicrobial potential of EOW with high oxidation reductive potential (ORP) and the presence of biocidal components such O 2 , Cl 2 , HOCl, OCl − , and HCl ( Figure 2) (Al-Haq & Gómez-López, 2012). ...
Listeria monocytogenes, in fresh and ready‐to‐eat produce such as whole fresh apples, is of concern as there is no “kill step” in their packing process that would eliminate the pathogenic bacteria. Recent listeriosis outbreaks revealed that insufficient cleaning and sanitation practices in fresh apple packing houses may lead to contamination of fruit with L. monocytogenes. This article discusses three fundamental aspects for ensuring microbiological safety of fresh apples: protection of fresh apples from microbial contamination during the packing process, decontamination intervention techniques, and the challenges in removal of L. monocytogenes from fresh apples. Currently used and novel methods of fresh produce decontamination are discussed and evaluated on their usefulness for the apple packing process. Additionally, present regulatory requirements, possible routes of produce contamination, and bacteria attachment and survival mechanisms are described. Optimum methods for microbial decontamination of whole fresh apples are still to be determined. Critical aspects that should be considered in developing the interventions include apple morphology, conditions and scale of the packing process, and influence of the interventions on apple quality. Evaluation of the currently used and emerging decontamination methods indicated that the hurdle technology and rotating use of sanitizers to avoid development of bacterial biofilm resistance may give the best results, although not conclusively.
... The exclusionary feature of water next to the surface of both materials ought to be regarded as a primary mechanism that triggers antifouling for micron-size foulants. Moreover, sericin elicits an acidic environment near the surface, enhancing the antimicrobial properties (especially against neutrophilic bacteria), as acidic water has been widely used as an antimicrobial agent (Hotta et al. 1994;Kiura et al. 2002). ...
Silk sericin is a globular protein whose resistance against fouling is important for applications in biomaterials and water-purification membranes. Here it is shown how sericin generates a water-exclusion zone that may facilitate antifouling behavior. Negatively charged microspheres were used to mimic the surface charge and hydrophobic domains in bacteria. Immersed in water, regenerated silk sericin formed a 100-µm-sized exclusion zone (for micron-size foulants), along with a proton gradient with a decrease of >2 pH-units. Thus, when in contact with sericin, water molecules near the surface restructure to form a physical exclusionary barrier that might prevent biofouling. The decreased pH turns the aqueous medium unviable for neutrophilic bacteria. Therefore, resistance to biofouling seems explainable, among other factors, on the basis of water-exclusionary phenomena. Furthermore, sericin may play a role in triggering the fibroin assembly process by lowering the pH to the required value.
... 7,8 Depending on the intended use, two different types of water as strong acidic EW (StAEW) and slightly acidic EW (SAEW) can be produced. 9 For example, StAEW is known to have a strong bactericidal effect on the most known pathogenic bacteria with its low pH, high ORP, and FCC. 10 On the other hand, SAEW has a nearly neutral pH, lower ORP value, and FCC. The SAEW has attracted much interest, because it contains low free chlorine, has less Cl 2 gas emissions, has low corrosive effects on surfaces, and is a highly effective antimicrobial agent with limited phytotoxic effects compared to hypochlorous acid derivatives. ...
Electrolyzed water (EW) is a widely used disinfectant agent with high oxidation–reduction potential (ORP). Although EW has been used in many areas, such as food hygiene, agriculture, and animal husbandry, the studies presented in the literature are not enough to clarify the toxic effects of EW. The aim of this study is, therefore, to produce EWs at different pH, ORP, and chlorine concentrations and to assess their safety in terms of toxicology. At the beginning of the study, the antimicrobial activity of the EW types with respect to bacteria and fungus was investigated. EWs below pH 7 were all effective in inactivating Enterococcus hirae, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans completely. In vitro studies of cell cultures revealed that different concentrations of EWs were not cytotoxic for the L929 cells under 10- to 80-fold dilutions. In addition, it has been determined that produced EWs did not have irritation potential, according to the in vitro EpiDerm ™ , reconstituted skin irritation test in the frames of biocompatibility tests. For the mucous membrane irritation test, the hen’s egg test-chorioallantoic membrane experiment was performed, and EWs were found to have no eye irritation. In conclusion, it has been shown that produced EWs with antimicrobial efficacy were found to be safe for skin and eye according to in vitro biocompatibility study studies. Thus, the establishment of a technological infrastructure for the EW production and the use of produced EW as an effective disinfectant in the food, medical, and agricultural areas should be encouraged.
... Hydroxyl radicals, which are generated from hypochlorous acid and hydrogen peroxide inside and outside the cell, act on the cell membrane, nucleic acids and proteins to cause damaging degradation. 126,127 Ozonated water is an aqueous solution that contains ozone, which is generated by applying high voltage or other forms of energy to oxygen molecules. It causes injury by reacting with S-S binding and SH-groups of proteins composing the cell wall and cell membrane, and also destroys nucleic acids by reacting with guanine residues and thymine residues of nucleic acids within the cell. ...
As part of the activities toward standardizing endoscopy procedures, the Japan Gastroenterological Endoscopy Society has prepared guidelines for cleansing and disinfection of gastrointestinal endoscopes. The environment of gastrointestinal endoscopy differs between Japan and advanced Western countries. In advanced Western countries, gastrointestinal endoscopy is performed almost exclusively at specialized facilities, where strict provisions are observed for cleansing and disinfecting endoscopes. In Japan, however, gastrointestinal endoscopy is performed even in small clinics, and the annual number of gastrointestinal endoscopy cases is enormous. In addition, the method for cleansing and disinfecting endoscopes differs among hospitals. Although there is a distinct lack of evidence for how gastrointestinal endoscopes are cleaned and disinfected, it is necessary to standardize the method for doing so to advance the field of endoscopic medicine. This article is protected by copyright. All rights reserved.
... The results showed three more SAEW production (total 9 SAEWs) in the combination of HCL + KCL compared to those in the combination of HCL + NaCl (total 6 SAEWs). When SAEW is applied to plant or plant components, potassium has a beneficial activity increasing cell osmotic pressure and stress tolerance, while sodium is capable to induce leaf edge dehydration and necrosis 16 . ...
The Influence of water source on the production of slightly acidic electrolyzed water (SAEW) and its sanitization efficacy were investigated. Two different water sources (tap water (TW) and underground water (UGW)) were applied to produce slightly acidic electrolyzed water (SAEW) at same setting current, with similar electrolyte flow rate (EFR) and concentration. Properties of SAEW were evaluated based on pH, Available chlorine concentration (ACC) and oxidation-reduction potential (ORP). Methods for the optimization of SAEW production process was examined to obtain high ACC value by implanting different types of electrolytes. Effect of ACC and pH of SAEW were evaluated in vitro towards inactivate foodborne pathogens. The results indicated that TW with hardness of 29 ppm produced effectively SAEW than through UGW (12 ppm) using electrolytes. Likewise, low water hardness could be reinforced by combining HCL with a salt (NaCl or KCL). The optimized SAEW production system was determined at 4% HCl + 2.0 M KCL with EFR of 2 mL/min and 4% HCl + 3.0 M KCL with EFR of 2 mL/min resulting in higher ACC value of 56.5 and 65.5 ppm, respectively using TW. Pathogenic vegetative cells were completely inactivated within 1 min of treatment in SAEW with 20 ppm. Viability observations using Confocal and TEM Microscopy, Flow cytometry, and antimicrobial activity were carried out to confirm the sanitizing effect and cell membrane disruption. Based on the experimental results obtained, it provides a foundation for future advancement towards commercial application of SAEW in the food and agricultural industries.
... The physiological and chemical characteristics of ESWA include a pH of 2.3-2.7; an oxidative-reduction potential (ORP) of 1000-1100 mV; and dissolvability in oxygen with a concentration of 10-30 ppm or 1.2 mM as hypochlorous acid (Kiura et al, 2002). ...
... The electrolyzed water (acid and not) is used for the treatment of surgical instruments, and has proved to be effective as a disinfectant both for animal products and for preservation or cold sterilization of food products (Huang et al., 2008). The antimicrobial activity of EAW is associated with the combination of free chlorine, low pH and high ORP, (Kiura et al., 2002;Abbasi and Lazarovitis, 2006;Huang et al., 2008). ...
Phaeomoniella chlamydospora (Pc) and Phaeoacremonium minimum (Pm) are among the main grapevine trunk disease pathogens affecting vines in the nursery. These pathogens can cause infections of the propagation material often appearing as dark wood streaking, and are associated with decline occurrence in young vineyards. The infection may occur during the grafting process, particularly during hydration. Promising preliminary results were obtained in the nursery using electrolyzed acid water (EAW) for the hydration of cuttings; EAW is characterized by low values of pH (2.5), high oxidation reduction potential (ORP>1000) and a certain amount of free chlorine. No differences in absorption kinetics were recorded between EAW and tap water, nor among 1103P, K5BB and SO4 rootstocks. In all combinations no significant additional absorption was observed after 7 h of immersion. In order to assess the characteristics of EAW after the contact with the inner plant tissues ORP and pH were measured from the liquid extracted from rootstocks after immersion in EAW. The values of the liquid, named “weakened” EAW (wEAW) (625–650 mV ORP and 3.1–3.3 pH), were significantly different from the values of both EAW and the liquid extracted after immersion in tap water. When the propagation material was hydrated for 7 h in EAW no significant effect on vegetating growth performance and percentage of certifiable plants was observed for SO4 or 1103P, whereas a reduction in plant vegetative growth was observed in K5BB hydrated vines at 12hr hydration. EAW and wEAW gave no significant reduction of in vitro mycelial growth, whereas a consistent decrease in conidial germination was observed in Pc and Pm. The three-year experiments carried out in the nursery on cuttings inoculated with Pc and hydrated in EAW showed a remarkable reduction of the infection level in the treated plants.
Sanitation is a compulsory procedure in the food industry. As it involves production downtime, it imposes overhead costs. One way to obtain higher profit margins is to cut the overhead costs of sanitation. Eco-innovative cleaners and sanitisers such as electrolysed water have a high potential to reduce sanitation costs. The only ingredients of electrolysed water are salt and distilled water. Some major food industries invest in expensive commercial electrolysed water generators to produce different types of electrolysed water (acidic, alkaline, and neutral). Smaller food industries can install an electrolysed water generator independently, but they need to determine the optimum and most economical electrolysing parameters. Different electrolysed water generators employ different electrolysing parameters to produce electrolysed water with the same physical and chemical properties. Thus, in this work, electrolysing parameter screening methods are demonstrated. A laboratory-scale electrolysed water generator was used to investigate the effects of different electrolysing parameters (voltages (1–20 V), electrolysis times (1–15 minutes), and sodium chloride concentrations (0.05–3%)) on the physical and chemical properties (pH, oxidation-reduction potential (ORP), and available chlorine concentration (ACC)) of electrolysed water (both acidic and alkaline). These screening methods were essential to determining the range of electrolysing parameters to use for the optimisation experiments and ascertaining the generator's limit. The subsequent optimisation experiments aimed to ensure the generator could be used for a long period and that economical usage conditions were achieved. The screening experiments helped to reduce the parameter variations in these experiments and provide reliable data on electrolysed water properties.
The food industry is dynamic. The needs and necessities of the consumer keep changing, and it becomes inevitable for the industry to fulfil those needs and eventually grow with them. In recent years, the food industry has grown immensely and has a greater market value. Nevertheless, on the flip side, it cannot go unnoticed that the food industry is one of those industries having a considerable impact on the environment. This alarming situation has led to the development of various green, sustainable technologies over the years, which can reduce the energy consumption that goes into the production, processing and packaging of food. This review focuses on five such green, nonthermal technologies: pulsed electric field, high-pressure processing, cold plasma, ozone, and electrolysed water. This review also discusses the sustainability and impact of each of these technologies on food products/materials.
Bacteria and their by-products are the primary cause of pulpal and periapical diseases that are one of the most common oral diseases. Root canal treatment (RCT) is the most effective procedure to treat pulpal and periapical diseases with severe infection. RCT aims to eliminate the infection from root canals and place filling materials to seal the space to prevent reinfection. Because of the complicated anatomical structure of the tooth root canal, complete elimination of the bacteria that reside in a root canal and the dentinal tubules via mechanical preparation is extremely difficult, if not impossible. Therefore, antimicrobial endodontic materials are indispensable for infection elimination during RCT. Based on the procedure of RCT, different antimicrobial endodontic materials have been developed for root canal irrigation, medication, and obturation (sealing). This chapter discusses the antimicrobial endodontic biomaterials that are used during the three steps of the RCT. Advantages and limitations of each material are emphasized. In addition, recent developments and future research directions of antimicrobial endodontic biomaterials are presented.
Salmonella spp. are among the most important pathogens in poultry farming, and Salmonella Heidelberg (SH) is one of the most frequent serotypes isolated in Brazil. SH has a zoonotic potential and stands out as a pathogen that is difficult to eliminate from the poultry chain due to its resistance to disinfectants. One alternative to traditional disinfectants is the electrochemically-activated water (ECA), a bactericidal compound produced from the electrolysis of salt and water. ECA generators produce a compound that consists of free chlorine, hypochlorous acid, and other free radicals. This alternative control method is safe for human health and reduces environmental contamination. The present study aimed at evaluating the efficacy of ECA against 30 SH isolates from poultry origin in scenarios that simulated the chiller environment (4°C, 5 and 50 parts per million [ppm], 5 and 40 min of exposure) and the cleaning and disinfection process (25°C, 200 ppm, 5 and 10 min of exposure). In the quantitative test, SH was susceptible to ECA. The mean bacterial counts decreased significantly compared to the control group, especially at 200 ppm. At this concentration, ECA inhibited the growth of almost 87% of the Salmonella strains, and the results showed a significant decrease in the mean bacterial counts for both exposure times (5 and 10 min). These findings demonstrate that ECA is effective against SH in vitro and it is a possible alternative to disinfection in the poultry industry for the control of this pathogen. However, in situ tests in the food industry are needed.
Electrolyzed water (EW) considered as a novel broad-spectrum and high-performance bactericide has gained immense popularity over the last few decades. It offers several advantages over other sanitizers for sanitation of both food contact and noncontact surfaces, such as safety, effective disinfection, easy operation, relatively inexpensive, and environmentally friendly. EW can be produced by electrolyzing soft tap water with sodium chloride as the chemical additive. Different producing equipment and parameters greatly influence the types and properties of EW. During production period, preparation settings are vital factors on the basic properties of EW (available chlorine concentration (ACC), pH, and oxidization reduction potential (ORP)) and then influence its inactivation efficiency, including current, water flow rate, salt/acid concentration, electrolyte and electrode, water temperature and hardness, storage environments, and so on. This chapter provides an overview of the production, properties, types of EW, as well as a section on its advantages and disadvantages.
Electrolyzed oxidizing water (EOW) can be divided into acidic electrolyzed oxidizing water (AEOW) and slightly acidic electrolyzed water (SAEW). AEOW has the characteristics of low pH (pH < 2.7) and high oxidation-reduction potential (ORP > 1100 mV). SAEW is slightly acidic (pH = 5-6) and has an ORP of 700-900 mV. AEOW and SAEW both have a certain amount of active chlorine content (ACC), so they have the characteristics of broad spectrum, rapidity and high efficiency of sterilization. At present, there is little systematic research on AEOW and SAEW preparation. However, it is very important to study the preparation process, including electrode material and electrolytic process. First, the effects of Pt electrodes with different thermal decomposition temperatures on AEOW's pH, ORP and ACC values were investigated in detail. Next, for the SAEW preparation, the process is based on the preparation of AEOW by ion-exchange membrane electrolysis, reasonably mixing the electrolyzed cathode and anode solution. The effects of technological conditions such as electrolysis time, current density and electrolyte concentration have been systematically studied, and it is expected to get SAEW with a pH value slightly less than 7, a higher ORP value and a certain amount of ACC.
Glutaraldehyde is used as a disinfectant for endoscopes, but is an irritant and so should be replaced by an alternative. Electrolysed acid water (EAW) has a bactericidal effect, and an endoscopic washing device using EAW has been developed in Japan. To investigate the effect of EAW on the infectivity of viruses, we treated duck hepatitis B virus (DHBV), which has similar properties to hepatitis B virus, with EAW, and determined the number of remaining infectious virus particles in a bioassay system. One-day-old Pekin ducks were inoculated with duck serum containing 105.5 ID 50 DHBV; the serum had previously been incubated with 100 volumes of EAW or ion-exchanged water at room temperature for 7 min. DHBV infection was indicated by detection of viral DNA in duck serum samples 1–8 weeks after inoculation. Treatment of serum with EAW diminished DHBV infectivity whereas treatment with ion-exchanged water did not. The virus load was estimated to have been reduced to 101–103 ID 50 during the first 1 min and to <100.5 ID 50 in the next 6 min of incubation when compared with the control. Thus, EAW directly inactivates DHBV and its clinical application is recommended.
The aim of the present study was to evaluate a new endoscope disinfector (WM-1) that uses acidic electrolytic water (AEW).
AEW was produced by electrolysis of a 0.05% NaCl-water mixture, with a redox potential greater than 1000 mV and a pH lower than 2.7. In the first study, an endoscope artificially contaminated with 15 species of bacteria and four strains of viruses was treated using the WM-1. In the second study, endoscopic contamination after clinical use was examined by culture for Helicobacter pylori and other bacteria, and by polymerase chain reaction for the H. pylori urease gene and hepatitis C virus. The extent of contamination was then examined after exposing the WM-1 to AEW. The safety of AEW was examined using both in vivo and in vitro studies.
All of the bacteria and viruses were destroyed or inactivated after the instrument had been exposed to AEW. Clinical contamination was detected from the instrument in 19 of 30 endoscopic procedures, whereas no bacteria or viruses were detected after five minutes' exposure to AEW. AEW was found to be nonirritant, nontoxic to cells, and nonmutagenic.
The WM-1 successfully and safely disinfected the endoscopes. With running costs of yen 24 per day ($0.21 per day), the WM-1 provides an effective and inexpensive alternative to conventional disinfection equipment.
Hypochlorite has been used as a disinfectant for more than 100 years. It has many of the properties of an ideal disinfectant, including a broad antimicrobial activity, rapid bactericidal action, reasonable persistence in treated potable water, ease of use, solubility in water, relative stability, relative nontoxicity at use concentrations, no poisonous residuals, no color, no staining, and low cost. The active species is undissociated hypochlorous acid (HOCl). Hypochlorites are lethal to most microbes, although viruses and vegetative bacteria are more susceptible than endospore-forming bacteria, fungi, and protozoa. Activity is reduced by the presence of heavy metal ions, a biofilm, organic material, low temperature, low pH, or UV radiation. Clinical uses in health-care facilities include hyperchlorination of potable water to prevent Legionella colonization, chlorination of water distribution systems used in hemodialysis centers, cleaning of environmental surfaces, disinfection of laundry, local use to decontaminate blood spills, disinfection of equipment, decontamination of medical waste prior to disposal, and dental therapy. Despite the increasing availability of other disinfectants, hypochlorites continue to find wide use in hospitals.
From November 1994 to August 1995, we used electrolysed hyperacidity water (EWH) to clean and disinfect hemodialysis equipment and several pipe lines. In order to clarify the effectiveness of EHW cleaning and disinfection, we carried out a comparative study with conventional disinfectant agents, sodium hypochlorite, acetic acid and formalin. The effectivenss of sterilization using EHW and the decrease of endotoxin level examined during the study. The effect of EHW disinfection appears immediately after using it and shows relatively high. In addition, EHW is more safe and easy to handle in comparison with other agents. Shorter rinse cycle and smaller amount usage in BHW are possible without other agents. Furthermore, the prevention of carbonate precipitation have become possible. Also, erosion caused by chloride gas has not been observed. Summary, EHW has many advantages to conventional disinfectant agents. An automated disinfection system using EHW will be effective for dialysat purification.
Concern is increasing regarding the risk of transmission of blood-borne pathogens by means of improperly reprocessed medical devices.
On-site surveys of policies and practices were performed in 18 reprocessing areas in eight randomly selected hospitals in Massachusetts to assess current practices for reprocessing of flexible fiberoptic endoscopes. Manufacturers' and internal written protocols, were reviewed, employees were interviewed, and procedures were observed. Reprocessing included high-level disinfection in 17 of 18 areas, with 16 areas using 2% glutaraldehyde; ethylene oxide gas sterilization was used in one area.
Considerable interhospital and intrahospital variability was found in high-level disinfection procedures, including equipment, contact time (range 10 to 45 minutes), disinfectant testing, and rinsing. Disinfection of internal channels was inadequate in three areas, recommended sterilization of biopsy forceps was not performed in five, and written protocols were unavailable in three. Ad hoc deviation from established written or verbal protocols occurred in eight areas during reprocessing of flexible fiberoptic endoscopes from patients known to have AIDS; ethylene oxide sterilization was used in seven areas and a separate device was used in one. Interviews with personnel revealed that lack of knowledge of high-level disinfection contributed to the discrepancies between policy and practice.
We conclude that reprocessing of flexible fiberoptic endoscopes is inconsistent and potentially ineffective. Knowledge that a flexible fiberoptic endoscope was used for a patient with AIDS influences practice.
Unlabelled:
OUTBREAK INVESTIGATION: An outbreak of diarrhea, bloody diarrhea, and abdominal cramps occurred among persons undergoing flexible sigmoidoscopy at a branch clinic of a local health center. Illness was associated with use of sigmoidoscopes cleaned by one clinic assistant and appeared to be caused by 2% glutaraldehyde disinfectant solution left in the instruments after cleaning.
Animal studies:
In subsequent animal studies, colonic instillation of 2% glutaraldehyde solutions caused bloody diarrhea and a distinctive pattern of mucosal damage; similar changes were seen in a review of pathologic samples from other human cases of glutaraldehyde disinfectant-associated diarrhea.
Conclusion:
Our data indicate that improper endoscopic reprocessing can result in serious illness and underscore the importance of adequate training and quality control in this area.
The cytotoxic and genotoxic effects of glutaraldehyde were studied in vitro in the human TK6 lymphoblast cell line and in primary cultures of rat hepatocytes. TK6 lymphoblasts were exposed to glutaraldehyde for 2 hr in serum-free GSH-free media. Cytotoxic effects were observed at concentrations as low as 10 microM with only 10% cell survival at 20 microM. Alkaline elution studies indicated that glutaraldehyde-induced DNA-protein crosslinking increased linearly over the concentration range from 0 to 25 microM. Glutaraldehyde-induced mutations were assessed at the thymidine kinase locus over the same concentration range and reached a plateau at 10 microM of about six times the background mutant frequency. At equivalent levels of DNA-protein crosslinks and cytolethality, glutaraldehyde was mutagenic at approximately a one-seventh lower concentration than the rodent nasal carcinogen formaldehyde (Craft et al.; Mutation Research 176:147-155, 1987). Glutaraldehyde induced a marginal increase in unscheduled DNA synthesis in the in vitro hepatocyte DNA repair assay, but only at the two highest concentrations of 50 and 100 microM, indicating the induction of some DNA excision-repair activity. These data demonstrate that glutaraldehyde exhibits DNA-reactive genotoxic activity that may involve, at least in part, DNA-protein crosslinking in these cell culture models. These findings suggest the need to examine the potential carcinogenic activity of glutaraldehyde in appropriate inhalation studies.
The emergence of HIV has provoked a widespread reappraisal of infection control practices in endoscopy units. Infection control practices should be applied to all patients alike without recourse to selection or screening. Although there has only been one reported instance of viral transmission at endoscopy, HIV could in theory be transmitted by a contaminated endoscope. Experience suggests that this is more likely to occur from damaged endoscopes, if an unsuitable disinfectant is used or endoscopes are not precleaned. In-use studies have shown that HIV contaminates endoscopes used on patients with AIDS, but in amounts too small to cause infection in tissue cultures. Cleaning in neutral detergent is extremely effective in removing contaminating micro-organisms, including HIV, from endoscopes. Aldehydes are the disinfectants of choice, but any disinfectant may fail if organic material is not removed by cleaning. After thorough cleaning, short disinfection times (e.g. four minutes) ensure inactivation of all relevant micro-organisms except Cryptosporidium and mycobacteria, although in practice even these organisms are likely to be reduced to non-pathogenic levels. Accidental needlestick injuries are the greatest hazard in the endoscopy suite; needles should not be resheathed and biopsy forceps must be handled with great care. The wearing of gloves should become second nature.
The interacting effects of time of exposure and concentration as factors in cytotoxicity were compared for glutaraldehyde and formaldehyde. Cells from a human fibroblast cell line (WI-38) grown to confluence in 24-well trays were exposed to a range of concentrations of each agent, for periods of 4 to 24 hr. Cytotoxicity was measured by its effects on mitochondrial dehydrogenase activity, as assayed biochemically. Cytotoxic effects of formaldehyde occurred over a narrow concentration range from nontoxic to maximally toxic, and the range was little affected by time of exposure. In contrast, glutaraldehyde exerted its effect over a wider concentration range, and longer exposure times were necessary for maximal toxicity. The data suggest that long contact times of glutaraldehyde with dental pulp are necessary for maximum fixation. While 19% formaldehyde appeared to be more toxic than 2.5% glutaraldehyde in terms of serial dilution, little difference in cytotoxicity was observed when the data were calculated in terms of molar concentrations of the two agents.
Serial dilution and agar overlay techniques were used to compare the cytotoxicity of formocresol, 19% formaldehyde, 35% cresol, and 2.5% glutaraldehyde to human pulp fibrob- lasts. The maximum nontoxic concentration of each agent was determined to allow quantitative comparisons both of the agents tested and of the techniques used. Formaldehyde was found to be the major component of formocresol which is responsible for the cytotoxic effect on human pulp fibroblasts. Two and one-half per cent glutaraldehyde was 15-20 times less toxic than either formocresol or 19% formaldehyde. Cresol measured 40 times less toxic than formaldehyde or formocresol. Both serial dilution and agar overlay techniques appear to be sensitive and effective methods for testing the toxicity of diffusible agents.
Glutaraldehyde (pentanedial) is a dialdehyde that displays potent bactericidal, fungicidal, mycobactericidal, sporicidal, and virucidal activity. Pertinent to its activity is its interaction with amino groups in proteins and enzymes, but this simplistic statement masks the manner in which it inactivates various types of microorganisms. Notwithstanding its toxicity for medical staff, glutaraldehyde remains an invaluable compound for high-level disinfection purposes in endoscopy units.
The introduction of chlorination of public drinking water in the early 1900's was a major factor in the fight against waterborne disease. In the 1970's it was discovered that chlorine reacted with naturally occurring organic constituents, particularly in surface water, to yield small quantities of chlorinated by-products such as chloroform for which regulations were subsequently developed. Since then there has been shown to be a substantial number of other by-products some in concentrations of a few nanograms/l and others similar concentrations to the THM. Of particular note are the potent bacterial mutagen MX and the chlorinated acetic acids. Current research into the significance of these for man is described and the key issues for risk assessment are identified.
The base substitution specificities of 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), 3-chloro-4-(chloromethyl)-5-hydroxy-2(5H)-furanone (CMCF), 3,4-dichloro-5-hydroxy-2(5H)-furanone (MCA), and chloromalonaldehyde (CMA), a putative breakdown product of MCA, were examined in the hisG46 gene and in the hisG428 gene of Salmonella typhimurium using allele specific oligonucleotide hybridization. Although the compounds are structurally closely related, they induced substantially different mutation spectra: MCA and CMA caused primarily GC-->AT transitions in the hisG46 allele (target sequence CCC), in particular, at the second position of the codon in strain TA100. In TA100 the mutation spectrum of MCA was similar to that of CMA. The mutational specificity of MCA can be explained as a consequence of misincorporation opposite to cyclic etheno adducts identical to those formed by the carcinogen vinyl chloride. The spectra induced by MX and CMCF in TA100 were almost identical but distinctively different from the spectra of MCA and CMA. Both compounds induced primarily GC-->TA transversions, in particular, at the second position of the codon, and to a lesser extent in the first position of the codon. An identical site bias is induced by carcinogens such as polycyclic aromatic hydrocarbons and heterocyclic amines as a consequence of formation of (noncyclic) guanosine adducts. In hisG428 (target sequence TAA) MX induced again primarily GC-->TA transversions in Tyr tRNA genes (supC/M) and, to a lesser extent, intragenic AT-->TA transversions (TAA-->AAA). The possible involvement of guanosine and adenosine adducts in the mutational specificity of MX is addressed.
Acidic electrolyzed water is made recently by various kinds of machines and is widely utilized. In this study, we intended to clarify the relationship between the concentration of chloride and pH in the bactericidal effects with acidic electrolyzed water. The effects of weak or strong acidic electrolyzed water were compared with a pseudo-acidic water of pH adjusted by diluted hydrochloric acid and sodium hydroxide, on Staphylococcus aureus, Staphylococcus epidermidis and Pseudomononas aeruginosa. At pH 5.0 approximately 6.0, 3 bacterial strains were killed soon after being exposed to the acidic water containing chloride 50 mg/liter, and the amount of chloride did not change after allowing to stand open for 6 hours. At pH 2.67 approximately 2.80, the bactericidal effects was observed at the concentration of chloride 5 mg/liter, and 80% of chloride remained after allowing to stand for 6 hours. These results indicated that newly made strong acidic water is more effective under a smaller amount of chloride at pH 2.7, and that weak acidic electrolyzed water should be used, if stable bactericidal effect is expected in cleaning the surroundings.
Hypochlorite has been used as a disinfectant for more than 100 years. It has many of the properties of an ideal disinfectant, including a broad antimicrobial activity, rapid bactericidal action, reasonable persistence in treated potable water, ease of use, solubility in water, relative stability, relative nontoxicity at use concentrations, no poisonous residuals, no color, no staining, and low cost. The active species is undissociated hypochlorous acid (HOCl). Hypochlorites are lethal to most microbes, although viruses and vegetative bacteria are more susceptible than endospore-forming bacteria, fungi, and protozoa. Activity is reduced by the presence of heavy metal ions, a biofilm, organic material, low temperature, low pH, or UV radiation. Clinical uses in health-care facilities include hyperchlorination of potable water to prevent Legionella colonization, chlorination of water distribution systems used in hemodialysis centers, cleaning of environmental surfaces, disinfection of laundry, local use to decontaminate blood spills, disinfection of equipment, decontamination of medical waste prior to disposal, and dental therapy. Despite the increasing availability of other disinfectants, hypochlorites continue to find wide use in hospitals.
Electrolyzed products of sodium chloride solution were examined for their disinfection potential against hepatitis B virus (HBV) and human immunodeficiency virus (HIV) in vitro. Electrolysis of 0.05% NaCl in tap water was carried out for 45 min at room temperature using a 3 A electric current in separate wells installed with positive and negative electrodes. The electrolyzed products were obtained from the positive well. The oxidation reduction potential (ORP), pH and free chlorine content of the product were 1053 mV, pH 2.34 and 4.20 ppm, respectively. The products modified the antigenicity of the surface protein of HBV as well as the infectivity of HIV in time- and concentration-dependent manner. Although the inactivating potential was decreased by the addition of contaminating protein, recycling of the product or continuous addition of fresh product may restore the complete disinfection against bloodborne pathogens.
Inactivation of Hepatitis B virus by high oxidation potential water
- S Abe
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Antimicrobial activity of aqua oxidized water
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Iwasawa, A., Nakamura, Y., 1993. Antimicrobial activity of aqua
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Antiviral activity of acid water
- Iwasawa
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