Atlantic salmon (Salmo salar) mounts systemic and mucosal stress responses to peracetic acid.

Peracetic acid (PAA), a strong organic peroxide, is considered a relatively sustainable disinfectant in aquaculture because of its broad effectivity against many pathogens at low concentrations and because it degrades spontaneously to harmless residues. The impacts of PAA on fish health must be determined before its use as either a routine disinfectant or chemotherapeutant. Here we investigated the systemic and mucosal stress responses of Atlantic salmon (Salmo salar) to PAA. In experiment 1, salmon were exposed to different nominal concentrations (0, 0.6, and 2.4 ppm) of PAA for 5 min, followed by a re-exposure to the same concentrations for 30 min 2 weeks later. Sampling was performed before exposure to PAA and at 2 h, 48 h, and 2 w after exposures. In experiment 2, fish were subjected to crowding stress prior to PAA exposure at 4.8 ppm for 30 min. The fish were sampled before exposure and 1 h, 4 h, and 2 w after. The two trials were performed in a recirculation system. Both systemic (i.e., plasma cortisol, glucose, lactate, total antioxidant capacity) and mucosal (i.e., expression of antioxidant coding genes in the skin and gills) stress indicators were affected by the treatments at varying levels, and it was apparent that the fish were able to mount a robust response to the physiological demands of PAA exposure. The cortisol levels increased in the early hours after exposure and returned to basal level afterwards. Prior exposure history to PAA did not markedly affect the levels of plasma lactate and glucose when fish were re-exposed to PAA. Crowding stress before PAA treatment, however, did alter some of the stress indicators (i.e., lactate, glucose and expression of antioxidant genes in the gills), suggesting that stress history serves as both a confounding and compounding factor on how stress responses to PAA are mobilised. Nonetheless, the changes were not substantial. Gene expression profile analyses revealed that the antioxidant system was more responsive to PAA in the gills than in the skin. The increased antioxidant capacity in the plasma, particularly at 2.4 ppm and higher, indicates that antioxidants were produced to neutralise the internal redox imbalance resulting from PAA exposure. In conclusion, the results show that salmon were able to mount a robust adaptive response to different PAA doses and exposure times, and a combined exposure to stress and PAA. These results underscore the potential of PAA as a chemotherapeutant for salmon at PAA concentrations commonly applied to control parasitic infestations.

Keratinocyte Cytotoxicity of Peracetic Acid Used as Sterilizing Agent for Implant Scaffolds.

Peracetic acid (PAA) has been used to sterilize biomaterial scaffolds and allografts before their implantation. Although the antimicrobial effectiveness of PAA is widely known, there are no studies investigating its cytotoxicity on keratinocytes. This study aimed to investigate the cytotoxicity of PAA concentrations on keratinocytes by growing HaCaT cells in culture medium. Different concentrations of PAA (control-untreated, 0.01, 0.1, 1, 10, 100, 200, 400, 800, 1200, 1600, and 2000 ppm) were added to the culture wells and allowed to be in direct contact with cells for up to 24 hours. Cytotoxicity was quantitatively and qualitatively determined by cell viability assay and analysis of morphological changes. Statistical analysis was performed with 1-way analysis of variance and Tukey test at 5% significance. Cells treated with 0.01 and 0.1 ppm followed the same morphological pattern of untreated cells, whereas cells treated with 1.0 ppm presented about 20% of floating cells and dark cytoplasmic granules. More than 50% of the cells treated with 10 and 100 ppm were destroyed, whereas the attached ones showed unclear and interrupted cell membranes. Concentrations of 1 ppm or greater had less than 64.4% of viable cells compared with the control group. This study concluded that exposure of keratinocytes to concentrations of 1 ppm or greater of PAA resulted in strong cytotoxic effects.

Occupational asthma caused by peracetic acid-hydrogen peroxide mixture.

BACKGROUND: Healthcare practice in the UK has moved away from using aldehyde disinfectants for the decontamination of endoscopes, in part due to the risk of respiratory sensitization. Peracetic acid (PAA) in combination with hydrogen peroxide (HP) is a commonly used alternative. AIM: We describe a case of occupational asthma (OA) diagnosed at our specialist occupational lung disease clinic and caused by occupational exposure to PAA-HP mixture, used as a disinfectant in an endoscope washer-disinfector machine. CASE REPORT: A 48-year-old man employed as a mycologist and environmental microbiologist at a Birmingham city hospital, UK, presented following an acute exposure to PAA-HP mixture causing lacrimation, burning optic pain and headache. He had also experienced symptoms suggestive of OA for the preceding 10 months, and the diagnosis was confirmed through OASYS analysis of serial peak expiratory flow measurements. He had been exposed to PAA-HP mixture whilst working in the endoscopy department for 12 months prior to the acute episode, and a subsequent specific inhalation challenge test was positive with a late asthmatic response to PAA-HP mixture. CONCLUSION: This case provides evidence for a sensitization mechanism in OA caused by PAA-HP mixture.

Health problems and disinfectant product exposure among staff at a large multispecialty hospital.

BACKGROUND: Hospital staff expressed health concerns after a surface disinfectant product containing hydrogen peroxide, peracetic acid, and acetic acid was introduced. We sought to determine if this product posed a health hazard. METHODS: An interviewer-administered questionnaire on work and health characteristics was completed by 163 current staff. Symptoms that improved away from work were considered work-related. Forty-nine air samples were taken for hydrogen peroxide, peracetic acid, and acetic acid. Prevalence ratios (PRs) were calculated using Poisson regression, and standardized morbidity ratios (SMRs) were calculated using nationally representative data. RESULTS: Product users reported higher prevalence of work-related wheeze and watery eyes than nonusers (P < .05). Workers in the department with the highest air measurements had significantly higher prevalence of watery eyes (PR, 2.88; 95% confidence interval [CI], 1.18-7.05) than those in departments with lower air measurements, and they also had a >3-fold excess of current asthma (SMR, 3.47; 95% CI, 1.48-8.13) compared with the U.S. CONCLUSIONS: This disinfectant product was associated with mucous membrane and respiratory health effects. Risks of mucous membrane irritation and asthma in health care workers should be considered in development of disinfection protocols to protect patients from hospital-acquired infections. Identification of optimal protocols that reduce worker exposures while maintaining patient safety is needed.

Effect of peracetic acid on biofilms formed by Listeria monocytogenes strains isolated from a Brazilian cheese processing plant

ABSTRACT This study aimed to investigate the effect of peracetic acid (PAA, 0.5%) on adherent cells of three strains of Listeria monocytogenes strains belonging to serotypes 4b and 1/2b that had been previously isolated from the environment of a Brazilian cheese plant. The assays were conducted using polystyrene microplates and stainless steel coupons and the adhered cells were treated with PAA for 60, 120 and 180 s. On stainless steel, biofilms were partially inactivated by PAA after 60 s and almost 100% of the cells were damaged within 180 s using epifluorescence microscopy with LIVE/DEAD® staining. On polystyrene microplates, PAA decreased (P<0.05) biofilm biomass produced by the three L. monocytogenes isolates at 60 s, when compared with controls (no PAA treatment). However, PAA did not completely eliminate L. monocytogenes cells on polystyrene microplates (decreasing 1.8-2.5 log cycles after treatment with PAA for 180 s). The correct concentration and contact time of PAA is critical for eliminating biofilms formed by L. monocytogenes on stainless steel surfaces, although further studies are needed for defining efficient PAA treatments to remove adherent cells of this pathogen on plastic polymers

Effects of two water disinfectants (chloramine T and peracetic acid) on the epidermis and gills of Garra rufa used in human ichthyotherapy.

Doctor fish (Garra rufa) have recently been used for aesthetic purposes and as a medical treatment in patients with psoriasis (ichthyotherapy). For this particular kind of human therapy it is essential to guarantee adequate hygienic conditions for both people and fish. The aim of this study was to test two concentrations of water disinfectants, chloramine T and peracetic acid, on Garra rufa to ascertain possible exposure damage to the epidermis and gills. Fish were exposed to 2 mg/l and 10 mg/l of chloramine T and to 15 microl/l and 45 microl/l of peracetic acid in a 40-minute static bath up to six times a day for one week. The epidermis and gills were checked for histological changes and the number of epidermal mucous cells, club cells and taste buds were quantified; mucous cells were also characterized histochemically to detect alterations in mucin production. No mortality or severe histological changes were found in treated or control fish. Cell count showed a significant increase (p < 0.05) in mucous cells (mean 49.1 +/- 6.7 vs 37.0 +/- 13.1 of controls) in animals treated with peracetic acid independently of the dose. Club cell number showed a significant (p < 0.05) decrease in fish treated with 2 mg/l of chloramine T (mean 74.3 +/- 15.6) and with 45 microl/1 of peracetic acid (mean 78.17 +/- 10.5) compared to controls (mean 107.0 +/- 19.2). Histochemical evaluation of mucous cells did not reveal changes in mucin type in fish exposed to the two disinfectants. The results suggest a good tolerability of Garra rufa to the two disinfectants at the concentrations tested.

Erratum to: the acaricidal efficacy of peracetic acid and deltamethrin against the fowl tick, Argas persicus, infesting laying hens.

The fowl tick, Argas persicus (Oken), is of veterinary importance as a parasite of poultry and wild birds. The antitick efficacy, in vitro and in vivo, of peracetic acid (PAA) and deltamethrin (DMT) was tested separately against A. persicus through the dipping technique. PAA (0.5%) was highly efficient against soft tick larvae (A. persicus), resulting in 100 % mortality after 2 min. The lethal concentrations LC50 and LC95 were 0.310 and 0.503 %, respectively. The lethal time values LT50 and LT95 were 5.34 and 40.00 min, respectively, after treatment with PAA (0.25%). Two minutes after exposure to DMT, LC50 and LC95 values were 0.0033 and 0.0052% (33.204 and 51.527 mg/L), respectively. The LT50 and LT95 values were 27.03 and 305.46 min, respectively, after treatment with 0.0025% DMT (25 mg/L). After dipping in PAA (0.5%), the chickens did not show respiratory signs or inflammation on the eyes and/or skin. By contrast, temporary coughing, sneezing, and ocular inflammations without dermatitis were observed in chickens dipped in DMT (0.005 % or 50 mg /L). Seven days posttreatment (PT), the reduction in the percentages of A. persicus infesting laying hens were 99.15 and 63.42% after dipping in PAA and DMT, respectively. However, complete elimination of the number of ticks occurred after 28 days PT with DMT. PAA inhibits molting effectively (28%) when compared with that of DMT (52%). Results indicated that PAA is a more potent and promising acaricide against A. persicus (in vitro and in vivo) than DMT.

Role of peroxyacetic acid, octanoic acid, malic acid, and potassium lactate on the microbiological and instrumental color characteristics of ground beef.

UNLABELLED: This study evaluated the effects of peroxyacetic acid (PAA), malic acid (MA), octanoic acid (OA), and potassium lactate (KL) followed by mixing with trisodium phosphate (TSP) and an ultra-chilled CO2 snow shower on microbial counts of Escherichia coli (EC), coliform (CF), aerobic plate count (APC), and Salmonella Typhimurium (ST) on inoculated beef trimmings and the instrumental color attributes of the resultant ground beef. Beef trimmings inoculated with EC and ST were treated with either 0.02% PAA; 2% MA; 0.04% OA; or 2% KL, followed by mixing with 10% TSP and rapid chilling with CO2 snow shower. Treated trimmings were then ground, packaged, displayed under simulated retail conditions, and sampled on days 1, 2, 3, 5, and 7 for microbial counts and instrumental color characteristics. PAA, MA, OA, and KL reduced (P < 0.05) the microbial counts of EC, CF, APC, and ST during display. Among treatments, OA was most effective on EC, CF, ST, and APC during retail display. Chilling beef trimmings with CO2 improved instrumental color characteristics of the produced ground beef but made little difference in reducing microbial counts during display. During retail display, ground beef produced from beef trimmings treated with antimicrobials tended to maintain redness, myoglobin redox form stability (630 nm/580 nm), and overall instrumental color characteristics. PRACTICAL APPLICATION: This research provides a practical and cost-effective decontamination technology for beef processors that can be immediately implemented in the ground beef production chain. Using antimicrobial intervention coupled with rapid chilling could benefit the meat industry by preserving the quality attributes of ground beef during retail display under aerobic packaging environment.

Effects of ozone, ultraviolet and peracetic acid disinfection of a primary-treated municipal effluent on the immune system of rainbow trout (Oncorhynchus mykiss).

Municipal sewage effluents are complex mixtures that are known to compromise the health condition of aquatic organisms. The aim of this study was to evaluate the impacts of various wastewater disinfection processes on the immune system of juvenile rainbow trout (Oncorhynchus mykiss). The trout were exposed to a primary-treated effluent for 28 days before and after one of each of the following treatments: ultraviolet (UV) radiation, ozonation and peracetic acid. Immune function was characterized in leucocytes from the anterior head kidney by the following three parameters: phagocytosis activity, natural cytotoxic cells (NCC) function and lymphocyte (B and T) proliferation assays. The results show that the fish mass to length ratio was significantly decreased for the primary-treated and all three disinfection processes. Exposure to the primary-treated effluent led to a significant increase in macrophage-related phagocytosis; the addition of a disinfection step was effective in removing this effect. Both unstimulated and mitogen-stimulated T lymphocyte proliferation in fish decreased dramatically in fish exposed to the ozonated effluent compared to fish exposed to either the primary-treated effluent or to aquarium water. Stimulation of T lymphocytes proliferation was observed with the peracetic acid treatment group. In conclusion, the disinfection strategy used can modify the immune system in fish at the level of T lymphocyte proliferation but was effective to remove the effects on phagocytosis activity.

A influência da imersão em ácido peracético sobre a reprodução de detalhes e compatibilidade dos elastômeros com gesso / The influence of peracetic acid immersion on detail reproduction and compatibility of elastomers with gypsum

O objetivo deste trabalho foi verificar a influência da imersão no desinfetante à base de ácido peracético 0,2% sobre a reprodução de detalhes e compatibilidade com gesso dos elastômeros: Silicona de Adição, Silicona de Condensação e Poliéter. Para a reprodução de detalhes foram confeccionados 10 corpos de prova de cada material utilizando-se a matriz determinada pela especificação n. 19 para Materiais de Impressão Elastoméricos Não-Aquosos da A.D.A., sendo que 5 corpos de prova foram imersos no desinfetante por 10 minutos e os outros 5, utilizados como controle. A reprodução de detalhes foi analisada pela visualização de uma linha de 30 mm de comprimento e 20 μm de espessura de forma completa e contínua em pelo menos duas de três impressões, segundo a especificação. Para compatibilidade com gesso avaliou-se a reprodução dos mesmos detalhes nos modelos vazados com gesso tipo IV sobre as referidas impressões. Todos os materiais utilizados apresentaram reprodução de detalhes e compatibilidade com gesso em 100% dos corpos de prova. Concluiu-se que a imersão no desinfetante à base de ácido peracético não alterou as propriedades avaliadas destes materiais.

In vitro potential genotoxic effects of surface drinking water treated with chlorine and alternative disinfectants.

A battery of in vitro short-term tests revealing different genetic end-points was set up in order to study surface-water genotoxicity after disinfection with different biocides: sodium hypochlorite (NaClO), chlorine dioxide (ClO(2)) and peracetic acid (PAA). The surface water both before and after disinfection was concentrated by adsorption on C(18) silica cartridges and the concentrates containing non-volatile organics were divided into different portions for chemical analyses and biological assays. The following in vitro tests were conducted on the water concentrates dissolved in DMSO: the Salmonella mutagenicity assay with S. typhimurium strains TA98 and TA100; the SOS Chromotest with Escherichia coli, the Microtox and Mutatox assays with Vibrio fischeri; and gene conversion, point mutation and mitochondrial DNA mutability assays with D7 diploid Saccharomices cerevisiae strain. The results show that the SOS Chromotest and the yeast assays are highly sensitive in detecting genotoxicity. The surface-water extracts were very often toxic to most of the test organisms considered, partially masking their potential mutagenic activity. Therefore, the assays with E. coli and with S. cerevisiae are more likely to show a mutagenic effect because these organisms are generally less sensitive to most toxic compounds. Among the tested disinfectants, NaClO and ClO(2) increased water genotoxicity, whereas PAA was able to slightly reduce raw water activity. However, because the organic compounds in the lake water varied with the season of the year, the disinfection processes, at times, both increased and decreased the raw water activity.

Genotoxicity of surface water treated with different disinfectants using in situ plant tests.

Disinfection of surface drinking water, in particular water chlorination, results in many by-products with potential genotoxic and/or carcinogenic activity. In the present study, we evaluated the genotoxicity of surface water after treatment with different disinfectants by means of in situ plant genotoxicity assays (micronucleus and chromosomal aberration tests) which can detect both clastogenic and aneugenic effects. The study was carried out at a pilot plant using lake water after sedimentation and filtration. This water supplied four stainless steel basins: three basins were disinfected with sodium hypochlorite, chlorine dioxide, and peracetic acid and the fourth basin containing untreated lake water was used as a control. Plants were exposed in situ in the basins. The study was carried out using water collected in different seasons over a period of about 1 year in order to assess the treatments in different physical and chemical lake water conditions. The micronucleus test in root cells of Vicia faba (Vicia faba/MCN test) revealed genotoxicity in many samples of disinfected water. The micronucleus test in Tradescantia pollen cells and the chromosome aberration test in root cells of Allium cepa showed genotoxic effects only in some disinfected samples, but also revealed genotoxicity in raw water. The results of the study indicated that the Vicia faba/MCN test was the most sensitive plant assay for disinfected water and that peracetic acid disinfection produced similar or lower genotoxicity than sodium hypochlorite or chlorine dioxide treatment.

Sensory irritation of acetic acid, hydrogen peroxide, peroxyacetic acid and their mixture in mice.

The expiratory bradypnoea indicative of upper airway irritation in mice was evaluated during a period of 60 min of oronasal exposure to acetic acid, hydrogen peroxide and peroxyacetic acid vapours. The airborne concentration resulting in a 50% decrease in the respiratory rate of mice (RD50) was calculated for each chemical. The concentration-response curves of acetic acid, hydrogen peroxide and peroxyacetic acid had similar slopes. The results did however show that the three chemicals had different irritant potencies. The RD50 values of acetic acid, hydrogen peroxide and peroxyacetic acid were 227, 113 and 5.4 p.p.m. respectively. Moreover, a mixture containing 53% acetic acid, 11% hydrogen peroxide and 36% peroxyacetic acid had an RD50 of 10.6 ppm, 3.8 ppm being peroxyacetic acid, which is 1.4 times lower than the theoretical value estimated from the fractional concentrations and the respective RD50s of the individual components. On the basis of a TLV-STEL (threshold limit value for short-term exposure limit) equal to 0.1 RD50, the TLV-STELs for acetic acid, hydrogen peroxide and peroxyacetic acid should not exceed 20, 10 and 0.5 p.p.m. respectively. On the basis of a TLV-TWA (time-weighted average) equal to 0.03 RD50, the TLV-TWAs for these same chemicals should not exceed 5, 3 and 0.2 p.p.m. respectively. Finally, these values and existing TLVs in Europe and the USA are compared.

Mutagenicity and disinfection by-products in surface drinking water disinfected with peracetic acid.

The aims of this research were to study the influence of peracetic acid (PAA) on the formation of mutagens in surface waters used for human consumption and to assess its potential application for the disinfection of drinking water. The results obtained using PAA were compared to those found with sodium hypochlorite (NaClO) and chlorine dioxide (ClO2). The Ames test, root anaphase aberration assay, and root/micronuclei assay in Allium cepa and Tradescantia/micronuclei test were used to evaluate the mutagenicity of disinfected samples. Microbiological tests were also performed, and disinfection by-products (DBPs) were identified using gas chromatography/mass spectrometry (GC/MS). A slight bacterial mutagenicity was found in raw lake and river water, and similar activity was detected in disinfected samples. A plant test revealed genotoxicity in raw river water, and microbiological analysis showed that PAA has bactericidal activity but lower than that of the other disinfectants. The DBPs produced by PAA were mainly carboxylic acids, which are not recognized as mutagenic, whereas the waters treated with the other disinfectants showed the presence of mutagenic/carcinogenic halogenated DBPs. However, additional experiments should be performed with higher concentrations of PAA and using water with higher organic carbon content to better evaluate this disinfectant.