Chemical Disinfection Research Articles

Insights into the antifungal activity and mechanisms of cinnamon components against Aspergillus flavus and Penicillium citrinum

Fungal spoilage of food and the excessive use of chemical disinfectants serves potential adverse effects on human health and the environment. Consequently, there is a growing interest in exploring natural alternatives, particularly plant-derived antimicrobial preservatives. Cinnamon extracts are known for their antifungal activity, but most research has focused on essential oils, rarely on other bioactive components. This study assessed the antifungal activity and underlying mechanisms of four components—trans-cinnamaldehyde, cis-2-methoxycinnamic acid, coumarin, and o-methoxycinnamaldehyde—extracted from Cinnamomum cassia Presl (cinnamon) against Aspergillus flavus and Penicillium citrinum. These cinnamon components can inhibit the two fungi strains at the minimum inhibitory concentration ranged from 0.30 to 8.55 mmol/L. These components can disrupt fungal cell membranes by enhancing relative electrical conductivity and cytoplasmic content leakage, reducing ergosterol content, and increasing malondialdehyde level. Additionally, they can affect fungal cell wall integrity, leading to the leakage of alkaline phosphatase and alterations in the contents of β-1,3-glucan and chitin. Moreover, the cinnamon components influenced the activities of malate dehydrogenase, succinate dehydrogenase, as well as adenosine triphosphate levels. The observed suppression of fungal contamination in A. flavus and P. citrinum suggests that these cinnamon components as potential natural antifungal agents.

Study on the effect of chlorogenic acid on the antimicrobial effect, physical properties and model accuracy of alginate impression materials.

Dental impressions are essential for accurately capturing the detailed anatomy of teeth and surrounding oral structures. However, these impressions often become contaminated with saliva and blood, making proper disinfection necessary. The application of chemical disinfectants has been associated with negative side effects, leading to suboptimal disinfection practices in clinical settings. The purpose of this study was to evaluate the effectiveness of chlorogenic acid (CA) as a disinfectant for alginate impression materials, the impact of CA disinfection on the physical properties and dimensional accuracy of alginate impressions was also investigated. The physical properties of alginate impression materials, such as elastic recovery, strain-in-compression, initial setting time, and fluidity, were assessed after mixing the alginate impression materials with three different concentrations of CA solution (10 mg/mL, 15 mg/mL, 20 mg/mL). To evaluate the antimicrobial effect of CA, alginate impressions mixed with a 10 mg/mL CA solution and impressions mixed with distilled water (control group) were contaminated with four types of microorganism: Escherichia coli, Staphylococcus aureus, Candida albicans, and Streptococcus pneumoniae. Following a five-minute incubation period, a CA solution at a concentration of either 50mg/mL, 55 mg/mL, or 60 mg/mL was sprayed on the samples for disinfection. Samples were collected at different time intervals (10 min, 20 min, 30min) and cultured to determine the number of colony-forming units (CFU/mL), providing insight into the antimicrobial efficacy of these CA solutions. The dimensional accuracy of alginate impressions was assessed in three groups: one with alginate impressions mixed with distilled water, another with alginate impressions sterilized with available chlorine (2,000 mg/L) mixed with distilled water, and the last group consisting of alginate impressions mixed with 10 mg/mL CA solution and sprayed with 60 mg/mL CA solution. Both the standard model and the plaster model underwent 3D scanning, and the data were processed and compared by software. The root mean square (RMS) was used as a parameter to evaluate the deviation between models. All alginate impression materials mixed with either 10 mg/mL, 15 mg/mL, or 20 mg/mL concentrations of CA solution met the ISO 21563 standard for elastic recovery, strain-in-compression, and fluidity. However, only the material mixed with a concentration of 10 mg/mL CA had an initial setting time within the range specified by the T-6505 Japanese industrial standard. The application of CA solution by mixing or spraying showed significant antimicrobial effects on Staphylococcus aureus, Escherichia coli, Candida albicans, and Streptococcus pneumoniae. There was no significant difference in the dimensional accuracy of the alginate impressions between the group of the CA solution applied, the blank group, or the chlorine intervention group.

Biocompatibility of 3D-printed vs. thermoformed and heat-cured intraoral appliances

ObjectivesThe development of additive manufacturing has the potential to revolutionize the fabrication of medical devices. This technology, also known as 3D printing, offers precise, cost-effective, and personalized approaches, which could be particularly beneficial in the production of intraoral appliances. Despite its promise, research on the biocompatibility of 3D-printed intraoral devices is still limited. Our study aims to address this gap.MethodsWe examined the cytotoxicity of materials processed via three techniques commonly used for the fabrication of different intraoral appliances: 3D printing (Dental LT Clear), thermoforming (Duran adjusted with Durasplint LC), and conventional heat-curing (Villacryl H Plus). We also investigated the impact of chemical or UVC disinfection on the biocompatibility of these materials. We assessed the biological effects induced in human gingival fibroblasts (HGFs) through both direct contact tests (MTT and LDH assays) and extract tests (PrestoBlue, DCF, and cell death type assays). Additionally, we observed changes in cellular morphology and migration rate under an inverted light microscope. The surface roughness of materials was evaluated using contact profilometry. Statistical analysis was conducted using two-way analysis of variance.ResultsOur findings suggest that all three fabrication techniques induced a slight cytotoxic effect in HGFs, as evidenced by both direct contact and extract tests. However, these materials could be considered nontoxic according to the ISO 10993-5:2009 norm, as the decrease in metabolic activity observed was always less than 30% compared to the untreated control.ConclusionThis novel study confirms that 3D printing may be a safe alternative to conventional methods for fabricating intraoral appliances. However, further tests assessing the long-term intraoral usage are still needed.

Chemical inactivation of two non-enveloped viruses results in distinct thermal unfolding patterns and morphological alterations

BackgroundNon-enveloped viruses, which lack a lipid envelope, display higher resistance to disinfectants, soaps and sanitizers compared to enveloped viruses. The capsids of these viruses are highly stable and symmetric protein shells that resist inactivation by commonly employed virucidal agents. This group of viruses include highly transmissible human pathogens such as Rotavirus, Poliovirus, Foot and Mouth Disease Virus, Norovirus and Adenovirus; thus, devising appropriate strategies for chemical disinfection is essential.ResultsIn this study, we tested a mild, hypoallergenic combination of a denaturant, alcohol, and organic acid (3.2% citric acid, 1% urea and 70% ethanol, pH4) on two representative non-enveloped viruses – Human Adenovirus 5 (HAdV5) and Feline Calicivirus (FCV)– and evaluated the pathways of capsid neutralization using biophysical methods. The conformational shifts in the capsid upon chemical treatment were studied using Differential Scanning Calorimetry (DSC), while the morphological alterations were visualized concurrently using Transmission Electron Microscopy (TEM). We found that while treatment of purified HAdV5 particles with a formulation resulted in thermal instability and, large scale aggregation; similar treatment of FCV particles resulted in complete collapse of the capsids. Further, while individual components of the formulation caused significant damage to the capsids, a synergistic action of the whole formulation was evident against both non-enveloped viruses tested.ConclusionsThe distinct effects of the chemical treatment on the morphology of HAdV5 and FCV suggests that non-enveloped viruses with icosahedral geometry can follow different morphological pathways to inactivation. Synergistic effect of whole formulation is more effective compared to individual components. Molecular level understanding of inactivation pathways may result in the design and development of effective mass-market formulations for rapid neutralization of non-enveloped viruses.

Essential oils application as Bacillus cereus antispore agent in food hygiene

Adherence of Bacillus cereus spores to dairy industry equipment is a serious problem, causing food spoilage and, occasionally, outbreaks of foodborne diseases. Antimicrobial essential oils (EOs) have been proposed as an alternative to synthetic disinfectants due to their environmentally friendly properties. The aim of this study was to assess the effect of Cymbopogon winterianus and Juniperus phoenicea EOs on planktonic and adherent B. cereus spores to stainless steel surfaces. Eleven strains of B. cereus were used in this study. The chemical composition of the C. winterianus and J. phoenicea oils was analyzed by gas chromatography (GC)/mass spectrometry (MS). Ninety components were identified for C. winterianus, being geranial (37 %), neral (29 %), beta-myrcene (16 %) and geraniol (4 %) the most abundant constituents. Twelve components were identified for J. phoenicea, being alpha-pinene (65 %) the most abundant constituent. The results of the minimal inhibitory concentration and minimal bactericidal concentration revealed that C. winterianus was the most effective EO (p < 0.05) against all eleven strains. In addition, there was a large log10 reduction (from 4.93 to 2.42; p < 0.05) between spores in planktonic form versus spores adhered to stainless steel surface. C. winterianus can be used for effective detachment of B. cereus spores capable to adhere and form biofilms on stainless steel surfaces, being a valid alternative for the development of natural disinfectant that may reduce negative effects of synthetic chemical disinfectants.

Production of biostable drinking water using a lab-scale biological trickling filter enriched with hydrogen-oxidizing bacteria

Safeguarding the drinking water quality remains a challenge from the production site to the tap. Alternatively to chemical disinfection, biostable drinking water could serve as a more sustainable approach to produce microbially safe drinking water and to maintain the microbial quality in the drinking water distribution system (DWDS). In this study, the potential of hydrogen-oxidizing bacteria (HOB) to produce biostable drinking water was examined in a continuous trickling filter supplied with hydrogen gas. A biofilm was naturally enriched for 5 months and the bacterial regrowth, invasion potential, and nutrient composition of the water were determined. Treatment improved the biostability significantly, and it is hypothesized that nutrient limitation, especially phosphorous, was a driving force. As a result, the regrowth and invasion potential were lowered, as shown with specific biostability bioassays. Overall, this study demonstrates the proof-of-concept of HOB for producing biostable drinking water through nutrient limitation.

Validity and reliability of chemical-based disinfectant use questionnaire in a sample of the Lebanese public community

IntroductionWorldwide, people heavily use chemical-based disinfectants to prevent the spread of COVID-19 with limited or no safety instructions. Awareness about the safe use of chemical-based disinfectants is highly recommended to...

Positive properties of a biological preparation based on the consortium genus bacillus

Abstract An experiment to study the use of a biological preparation was carried out on spring wheat in plot experiments in the conditions of the northern forest-steppe. A fungicidal seed protectant, a bacterial preparation BP (Bacillus simplex / B. Megaterium consortium, secondary metabolites, titer 108 Coe/ml), Biocoal were studied. When treating seeds, plant development was 7 days higher than control when using BP at a rate of 2.5 l/t, where an increase in sprout length by 1.25 cm was noted. When applying the drug to day-old seedlings, the use of BP variants in pure form and with biochar at a rate of 5.0 l/t had a greater effect with an increase in the length of the sprout by 3.2-4.2 cm, a decrease in the population of pathogenic fungi in seeds at the level of 60%, stimulating effect on root length by 1.7 cm, sprout length by 1.5 cm and germination by 6-8%. The use of a bacterial preparation during seed treatment did not affect the reduction of crop root disease. Measuring plant development parameters in the tillering phase, BP with a rate of 1.5 l/t had a greater effect on the length of the upper leaf, exceeding the control by 1-2 cm. The development of morphometric parameters of the flag leaf in the filling phase - milky ripeness had a leaf length of 18-23 cm with a width of 1.0-1.2 cm, with an increase at BP rates of 2.5-5.0 l/t. For seed treatment options, the impact at this stage is minimal or absent. Taking into account biometric indicators of the mass of formed plant organs showed an excess of indicators for BP options in pure form and with biochar at a rate of 5.0 l/t when treating seeds and using them during the growing season. Structural analysis of the ear determined a significant excess of the results of the preparations used during the growing season; the weight of 1000 grains was higher by 2-3 g when the seeds were treated with a chemical disinfectant and using BP at rates of 2.5-5.0 l/t. The crop yield increased by 0.1 t/ha in variants with a rate of bacterial preparation BP of 2.5-5.0 l/t in its pure form.

Peracetic Acid Emissions and Exposures during Building Disinfection Events

Since the onset of the COVID-19 pandemic, there has been a significant increase in chemical disinfection of high-touch surfaces in buildings. Peracetic acid (PAA) is a commercially available and widely used disinfectant for inactivation of viruses and bacteria. The objective of this study is to evaluate indoor PAA emissions and exposures during full-scale building disinfection events via real-time PAA measurement in a test house. The measurements revealed that PAA-based surface disinfection can lead to a significant increase in PAA concentrations in indoor air (0.1–1 mg/m3). PAA emission factors (EFs) for spray-based products ranged from 0.22–0.59 mg of PAA emitted per mg of PAA sprayed, indicating that a significant fraction of the PAA applied to surfaces is emitted into the indoor atmosphere. Inhalation intake fractions (iFs) ranged from 1,597–3,436 ppm for a one-hour exposure period, demonstrating that around 0.16–0.34% of the PAA emitted into indoor air can be inhaled by an occupant during a disinfection event. iFs were similar between the active disinfection period and the subsequent concentration decay period, suggesting that inhalation intake is important both during and after the disinfectant is applied. Real-time breathing zone (BZ) experiments demonstrated that occupants can be exposed to elevated PAA concentrations beyond those measured in the bulk indoor air due to the source-to-BZ proximity effect inherent in disinfection processes. The PAA EFs enabled modeling of PAA dynamics in different indoor environments. Model results show that PAA concentrations often exceed exposure limits, indicating a need for improved exposure mitigation strategies.

Специфика фототрофных наземных микробных комплексов в посевах пшеницы

The article presents the results of determining the species and quantitative composition of algae and cyanobacteria in terrestrial growths under wheat crops. The wheat seeds were inoculated with various microorganisms in mono-, binary and triple combinations before sowing. Algocyanoflora of the “blooming” soil was represented by 24 species: Cyanobacteria – 7; Chlorophyta + Streptophyta – 12; Bacillariophyta – 5. The inoculants were representatives of prokaryotic and eukaryotic microorganisms – antagonists of Fischerella muscicola, Trichoderma sp. and the phytopathogen Fusarium culmorum. In one of the experimental variants, pre-sowing treatment with the fungicide “Maksim”® was used. It has been shown that during the formation of soil “blooming” the dominant microbiomes are green algae (Chlorococcum infusionum, Klebsormidium flaccidum) and cyanobacteria (species of the genera Leptolyngbya, Phormidium). When determining the number of phototrophic populations, it was found that their density ranges from 1.8 to 8.1 million cells/cm2. At the same time, the maximum development of phototrophs was found in the control variant, and the minimum number was found in the variant with a chemical disinfectant. In variants with microbial inoculation, the peak development of microphototrophs is typical for treatment with a triple mixture and a binary mixture of Fischerella + Trichoderma. Determination of the structure of microbial populations showed that the strongest dominance of cyanobacteria (80,2%) was detected on an artificial infectious background caused by pre-sowing inoculation of wheat seeds with the phytopathogen F. culmorum. A relatively high content of cyanobacteria (up to 60%) is observed in 4 experimental variants (Fischerella, Fischerella + Trichoderma, Trichoderma + Fusarium, Fischerella +Fusarium) and in the remaining 4 variants there is some dominance of microscopic algae ranging from 52 to 58%. Therefore, according to the results obtained, microbial inoculation does not lead to radical changes in the state of terrestrial phototrophic microbial communities, while chemical fungicide significantly suppresses the development of algae and cyanobacteria.

State-level regulation of disinfection byproducts in the United States

ABSTRACT Disinfection byproducts (DBPs), residual compounds formed from the chemical disinfection of drinking water, can cause a host of damaging public health and environmental impacts. This study evaluates the landscape of regulations designed to reduce the occurrence and/or impact of DBPs, focusing on regulations issued by the US states. Drawing on a systematic search of state administrative codes and agency websites, we first identify the presence, absence, and layering of DBP-related regulations. We then evaluate the number and types of policy tools – the specific approaches required by each regulation, such as monitoring requirements, economic incentives, and required treatment technologies – to identify how DBPs are being managed and how states cluster with relatively more and less robust regulatory frameworks. Finally, we evaluate the relationship between the regulatory approach and the frequency of drinking water quality violations for DBP compounds. While most states have at least one DBP-specific regulation, these vary substantially in their comprehensiveness. The most-used policy tools (monitoring, compliance schedules, and reporting) directly reflect federal regulations; few states have adopted innovative tools such as collaboration or financial incentives. We observe no relationship between regulatory efforts and water quality violations, suggesting that current policy implementation may not adequately address the complex risk of DBPs.

Off-site production of plasma-activated water for efficient disinfection: The crucial role of high valence NOx and new chemical pathways

Efficient disinfection of pathogens is a critical concern for environmental disinfection and clinical anti-infective treatment. Plasma-activated water (PAW) is a promising alternative to chemical disinfectants and antibiotics for its strong disinfection ability and not inducing any acute toxicity. Previous plasma sources are commonly placed near or fully in contact with water as possible for more efficient activation, but the risk of electrode corrosion and metal particle contamination of water threatens the safety and stability of PAW. In this work, plasma-activated gas (PAG) rich in high-valence NOx is generated by a hybrid plasma configuration and introduced into water for off-site PAW production. It is found that plasma-generated O3 dominates the gas-phase reactions for the formation of high-valence NOx. With the time-evolution of O3 concentration, the gaseous NO3 radicals are produced behind N2O5 formation, but will be decomposed before N2O5 quenching. By decoupling the roles of gaseous NO3, N2O5, and O3 in the water activation, results show that short-lived aqueous species induced by gaseous NO3 radicals play the most crucial role in PAW disinfection, and the acidic environment induced by N2O5 is also beneficial for microbial inactivation. Moreover, SEM photographs and biomacromolecule leakage assays demonstrate that PAW disrupts the cell membranes of bacteria and thus achieves inactivation. In real-life applications, an integrated device for off-site PAW production with a yield of 2 L/h and a bactericidal efficiency of >99.9 % is developed. The PAW of 50 mL produced in 3 min using this device is more effective in disinfection than 0.5 % NaClO and 3 % H2O2 with the same bacterial contact time. Overall, this work provides new avenues for efficient PAW production and deepens insights into the fundamental chemical processes that govern the reactive chemistry in PAW for environmental and biomedical applications.

Zagrożenia związane ze stosowaniem chemicznych środków dezynfekcyjnych i maseczek chroniących przed zakażeniem podczas epidemii

Risks related to the use of chemical disinfectants and masks using to protect against infection during an epidemic Actions to prevent the spread of pathogenic microorganisms are inextricably linked to medical activities and health services, they are indispensable in the activities of beauty and hairdressing salons, in agriculture, food production and animal breeding, the food industry, and during an epidemic or pandemic, they also apply to the general public. In addition to the benefits that such activities bring to health, one should be aware that the use of measures to protect against infection may also be associated with adverse effects for people who use them. The article discusses the risks associated with the use of chemical disinfectants and face masks protecting the respiratory system against the penetration of viruses. Keywords: chemical disinfectants, face masks, infections, hazards, epidemic

Comparative evaluation of the effects of laser and chemical denture disinfectants on the surface characteristics of CAD‐CAM and conventional denture resins: An in vitro experimental study

Comparative evaluation of the effects of laser and chemical denture disinfectants on the surface characteristics of CAD‐CAM and conventional denture resins: An in vitro experimental study

Bacterial Inactivation Studies in Shrimp Pond Water by using Different Disinfectant Agents

Abstract Background Aquaculture water plays an important role in the dissemination of antibiotic-resistant bacteria during harvest of shrimps. Mitigation of bacteria through discharge is essential to prevent dissemination downstream. Chemical disinfection of culture water is feasible compared to other methods of bacterial inactivation. Objective To study the effect of different disinfectant agent’s viz., chlorine, Fenton’s reagent, and hydrogen peroxide (H2O2) on inactivation of bacteria from shrimp pond water Methods The water samples were subjected to treatment with various concentrations of chlorine (0.0, 1.0, 2.5, 5.0 and 10.0 mg L−1), Fenton’s reagent (1:10 mM ratio of Fe2+:H2O2; 2:20, 3:30, 4:40, 5:50) and H2O2 (20, 30, 40 and 50 mM) for different time durations (5 min, 15 min, 30 min and 60 min). Results The results indicated that all the disinfecting agents inactivated both the total heterotrophic bacteria and tetracycline-resistant bacteria with increased concentrations and time. At the end of 60 min treatment with chlorination (2.5 mg Cl2 L−1), Fenton’s reagent (2 mM Fe2+ + 20 mM H2O2) and H2O2 (50 mM H2O2), the total heterotrophic bacterial count in the water samples gradually decreased by 2.35, 2.65, and 1.38 log10 CFU mL−1, and tetracycline-resistant bacteria count reduced by 1.57, 1.66, and 1.43 log10 CFU mL−1, respectively from initial bacterial load. Conclusions The study revealed that disinfection agents can be successfully employed in the inactivation of antibiotic-resistant bacteria discharged through aquaculture water. Among three disinfection agents, Fenton’s reagent has been found effective in inhibiting both heterotrophic bacteria and tetracycline-resistant bacteria from water samples. Highlights Bacterial inactivation studies were carried with Chlorination, Fenton’s reagent, and Hydrogen peroxide. The highest decrease in HPC (2.65 log) and tetracycline-resistant bacterial (1.66 log) was noticed in the water samples treated with Fenton’s reagent. The use of disinfection agents effectively mitigates antibiotic-resistant bacteria from aquaculture wastewater.

Comparative life cycle assessment of hospital waste management scenarios in Isfahan, Iran: Evaluating environmental impacts and strategies for improved healthcare sustainability

This study presents a life cycle assessment (LCA) of hospital waste management scenarios in Isfahan, Iran. Daily hospital waste generation totals 20 tons, with 44 % infectious and 56 % non-infectious waste. The non-infectious stream comprises 40 % food waste. Pyrolysis, chemical disinfection, composting, and material recovery were evaluated across ten environmental impact categories using TRACI 2014 methodology. Composting and material recovery reduce smog-forming emissions by 126.79 kg O3 eq/ton and 129.02 kg O3 eq/ton, respectively, and fossil fuel depletion by 255.04 MJ surplus/ton and 471.97 MJ surplus/ton compared to incineration. Chemical disinfection of infectious waste shows lower global warming potential (859.89 kg CO2 eq/ton) than pyrolysis (1483.15 kg CO2 eq/ton). The third scenario, prioritizing composting and material recovery, minimizes ecotoxicity with lowest emissions of cadmium (0.33 g/ton) and nickel (16.23 g/ton) to air, and arsenic (0.003 g/ton) and chromium (0.28 g/ton) to water. This study addresses a rarely assessed system in LCA literature, offering valuable insights for improving waste management in similar contexts worldwide. Recommendations include developing regulatory frameworks, investing in infrastructure, promoting collaboration, implementing training programs, and adopting circular economy principles. The research contributes to building life cycle thinking capability within the Iranian healthcare sector through stakeholder engagement, workshops, and public dissemination of findings.

Contamination patterns of the neonatal equipment, major microorganisms, and effectiveness of disinfection procedures including refurbished UV C lights at the University Teaching Hospital of Butare (CHUB)

A contaminated environment plays a significant role in transmitting hospital-acquired infections (HAIs) but regular chemical disinfection is the backbone for tackling this chain of transmission and the combination of both UV lights may increase the effectiveness of cleaning. This study assessed the effectiveness of chemical disinfection, with and without additional UV light exposure, in reducing bacterial contamination in a Neonatal unit. Therefore, interventions consisted of usual chemical disinfection with and without a 2-hour exposure to Ultraviolet light from refurbished UV lamps. Researchers swabbed high-touch surfaces and equipment before and after disinfection to identify bacterial presence. They found that 36.4% of the sampled sites showed bacterial growth, with the nursing trolley being the most contaminated. The most common bacteria isolated was Klebsiella pneumoniae (50%), which, along with other bacteria, displayed high resistance to commonly used antibiotics like Amoxicillin + Clavulanic acid and Cefuroxime. Only Meropenem and Amikacin remained effective. The study concludes that despite chemical disinfection, bacterial contamination remains significant, and conventional UV light alone did not completely eradicate bacteria, highlighting the need for more effective disinfection strategies. Keywords: Neonatology Service, University Teaching Hospital of Butare (CHUB), hospital-acquired infections (HAIs), disinfection

Reuterin Enhances the Efficacy of Peracetic Acid Against Multi-species Dairy Biofilm.

Biofilms may contain pathogenic and spoilage bacteria and can become a recurring problem in the dairy sector, with a negative impact on product quality and consumer health. Peracetic acid (PAA) is one of the disinfectants most frequently used to control biofilm formation and persistence. Though effective, it cannot be used at high concentrations due to its corrosive effect on certain materials and because of toxicity concerns. The aim of this study was to test the possibility of PAA remaining bactericidal at lower concentrations by using it in conjunction with reuterin (3-hydroxypropionaldehyde). We evaluated the efficacy of PAA in pure form or as BioDestroy®, a PAA-based commercial disinfectant, on three-species biofilms formed by dairy-derived bacteria, namely Pseudomonas azotoformans PFlA1, Serratia liquefaciens Sl-LJJ01, and Bacillus licheniformis Bl-LJJ01. Minimum inhibitory concentrations of the three agents were determined for each bacterial species and the fractional inhibitory concentrations were then calculated using the checkerboard assay. The minimal biofilm eradication concentration (MBEC) of each antibacterial combination was then calculated against mixed-species biofilm. PAA, BioDestroy®, and reuterin showed antibiofilm activity against all bacteria within the mixed biofilm at respectively 760ppm, 450ppm, and 95.6mM. The MBEC was lowered significantly to 456ppm, 337.5ppm, and 71.7mM, when exposed to reuterin for 16h followed by contact with disinfectant. Combining reuterin with chemical disinfection shows promise in controlling biofilm on food contact surfaces, especially for harsh or extended treatments. Furthermore, systems with reuterin encapsulation and nanotechnologies could be developed for sustainable antimicrobial efficacy without manufacturing disruptions.

EVALUATION OF THE CYSTICIDAL ACTIVITY OF CHLOROCRESOL AGAINST ACANTHAMOEBA POLYPHAGA.

Chlorocresol has antibacterial and antifungal properties, yet its effectiveness in eradicating Acanthamoeba spp. remains unexplored. Acanthamoeba species trophozoites are usually sensitive to biocides, whereas cysts tend to be more resistant. This study aimed to evaluate the cysticidal activity of chlorocresol against Acanthamoeba polyphaga. Chlorocresol concentrations of 0.02, 0.04, and 0.08% were prepared and A. polyphaga cysts were incubated at room temperature (28-37 C) for 1, 24, 48, and 72 hr at each concentration. Cyst viability was evaluated using trypan blue staining and the percentage of nonviable cysts was calculated. For qualification assays, treated cysts were cultured on nonnutrient agar medium coated with Escherichia coli, incubated at 30 C, observed under a stereomicroscope for 30 days, and inoculated into peptone-yeast extract-glucose medium at 30 C for 72 hr. The results revealed that the A. polyphaga cysts were susceptible to 0.02, 0.04, and 0.08% chlorocresol. Chlorocresol made a significant difference in viability (P < 0.001) compared with the nontreated control for the same incubation time. This is the first study to examine the efficacy of chlorocresol against A. polyphaga cysts and it was highly effective. Chlorocresol could thus serve as an alternative chemical disinfectant for the eradication of A. polyphaga cysts as well as a prophylactic against transmission of other pathogenic microorganisms for which Acanthamoeba species can act as a carrier.

Bio-Innovative Modification of Poly(Ethylene Terephthalate) Fabric Using Enzymes and Chitosan.

This article investigates the activation of surface groups of poly(ethylene terephthalate) (PET) fibers in woven fabric by hydrolysis and their functionalization with chitosan. Two types of hydrolysis were performed-alkaline and enzymatic. The alkaline hydrolysis was performed in a more sustainable process at reduced temperature and time (80 °C, 10 min) with the addition of the cationic surfactant hexadecyltrimethylammonium chloride as an accelerator. The enzymatic hydrolysis was performed using Amano Lipase A from Aspergillus niger (2 g/L enzyme, 60 °C, 60 min, pH 9). The surface of the PET fabric was functionalized with the homogenized gel of biopolymer chitosan using a pad-dry-cure process. The durability of functionalization was tested after the first and tenth washing cycle of a modified industrial washing process according to ISO 15797:2017, in which the temperature was lowered from 75 °C to 50 °C, and ε-(phthalimido) peroxyhexanoic acid (PAP) was used as an environmentally friendly agent for chemical bleaching and disinfection. The influence of the above treatments was analyzed by weight loss, tensile properties, horizontal wicking, the FTIR-ATR technique, zeta potential measurement and SEM micrographs. The results indicate better hydrophilicity and effectiveness of both types of hydrolysis, but enzymatic hydrolysis is more environmentally friendly and favorable. In addition, alkaline hydrolysis led to a 20% reduction in tensile properties, while the action of the enzyme resulted in a change of only 2%. The presence of chitosan on polyester fibers after repeated washing was confirmed on both fabrics by zeta potential and SEM micrographs. However, functionalization with chitosan on the enzymatically bioactivated surface showed better durability after 10 washing cycles than the alkaline-hydrolyzed one. The antibacterial activity of such a bio-innovative modified PET fabric is kept after the first and tenth washing cycles. In addition, applied processes can be easily introduced to any textile factory.