Cleaning products: Their chemistry, effects on indoor air quality, and implications for human health.

The use of cleaning and disinfecting products both at work and at home increased during the COVID-19 pandemic. Those products often include surfactants, acids/bases, carcinogens such as chloroform, and endocrine-disrupting chemicals, such as cyclosiloxanes, phthalates, and synthetic fragrances, which may cause harmful health effects among professional cleaners as well as among people exposed at home or in their workplaces. The aim of this study was to synthesize the effects of the commonly used chemical, surface cleaning and disinfecting products on indoor air quality, focusing on chemical and particulate matter pollutants, exposure, and human health in residential and public buildings. We also provide a summary of recommendations to avoid harmful exposure and suggest future research directions. PubMed, Google Scholar, Scopus, and Web of Science (WoS) were used to search the literature. Analysis of the literature revealed that the use of cleaning products and disinfectants increase occupants' exposure to a variety of harmful chemical air contaminants and to particulate matter. Occupational exposure to cleaning and disinfectant products has been linked to an increased risk of asthma and rhinitis. Residential exposure to cleaning products has been shown to have an adverse effect on respiratory health, particularly on asthma onset, and on the occurrence of asthma(-like) symptoms among children and adults. Efforts to reduce occupants' exposure to cleaning chemicals will require lowering the content of hazardous substances in cleaning products and improving ventilation during and after cleaning. Experimentally examined, best cleaning practices as well as careful selection of cleaning products can minimize the burden of harmful air pollutant exposure indoors. In addition, indirect ways to reduce exposure include increasing people's awareness of the harmfulness of cleaning chemicals and of safe cleaning practices, as well as clear labelling of cleaning and disinfecting products.

Evaluation of haemolymph phenoloxidase activity from the grub of Zophobas morio as a predictor of immune response.

In insects, enzyme phenoloxidase plays a critical role in cuticular sclerotisation and defensive functions. In the present investigation, haemolymph phenoloxidase activity from the grub of Zophobas morio was attempted to evaluate as a reliable predictor of insect's immunological response. Among the various substrates tested, L-DOPA was chosen as an appropriate substrate due to its high oxidation. The optimum pH and temperature for haemolymph PO activity was found to be 8 and 30 °C, respectively. The optimum substrate concentration of L-DOPA was found to be 7.5 mM for subsequent PO enzymatic characterisation. Among the various chemical inhibitors and copper chelators, PO activity was significantly reduced in the case of PMSF and thiourea. Preincubation of haemolymph with non-self-molecules showed enhancement of PO activity in the case of LPS from Serratia marcescens. In addition, exogenous proteases like α-chymotrypsin enhanced the PO activity of haemolymph and an increase in PO activity was demonstrated when haemolymph was preincubated with the anionic detergent, SDS and cationic detergent, cetyl pyridium chloride. Alteration of PO activity was observed under agonising conditions of starvation, ligation and microplastics injection at different time intervals. Interestingly, there were no correlation between PO and insect defence under live challenge of microbes. SDS protein profile revealed a significant increase in the 85 kDa and 55 kDa polypeptides in all the experiments over control after 24 h, 48 h and 96 h. Mass spectrophotometric analysis of the polypeptides revealed their homology to antimicrobial peptides for 55 kDa protein and 85 kDa protein. A significant increase in 85 kDa polypeptide was observed in the haemolymph of the grubs after 72 h in the case of starved and microplastics injected groups only. These results demonstrated that PO may not be a reliable benchmark of immunological response in this insect.

Cyclic pressure induced decellularization of porcine descending aortas.

The demand for decellularized xenogeneic tissues used in reconstructive heart surgery has increased over the last decades. Complete decellularization of longer and tubular aortic sections suitable for clinical application has not been achieved so far. The present study aims at analyzing the effect of pressure application on decellularization efficacy of porcine aortas using a device specifically designed for this purpose. Fresh porcine descending aortas of 8 cm length were decellularized using detergents. To increase decellularization efficacy, detergent treatment was combined with pressure application and different treatment schemes. Quantification of penetration depth as well as histological staining, scanning electron microscopy, and tensile strength tests were used to evaluate tissue structure. In general, application of pressure to aortic tissue does neither increase the decellularization success nor the penetration depth of detergents. However, it is of importance from which side of the aorta the pressure is applied. Application of intermittent pressure from the adventitial side does significantly increase the decellularization degree at the intimal side (compared to the reference group), but had no influence on the penetration depth of SDC/SDS at both sides. Although the present setup does not significantly improve the decellularization success of aortas, it is interesting that the application of pressure from the adventitial side leads to improved decellularization of the intimal side. As no adverse effects on tissue structure nor on mechanical properties were observed, optimization of the present protocol may potentially lead to complete decellularization of larger aortic segments.

Optimized production of keratinolytic proteases from Bacillus tropicus LS27 and its application as a sustainable alternative for dehairing, destaining and metal recovery.

The present study describes the isolation and characterization of Bacillus tropicus LS27 capable of keratinolytic protease production from Russell Market, Shivajinagar, Bangalore, Karnataka, with its diverse application. The ability of this strain to hydrolyze chicken feathers and skim milk was used to assess its keratinolytic and proteolytic properties. The strain identification was done using biochemical and molecular characterization using the 16S rRNA sequencing method. Further a sequential and systematic optimization of the factors affecting the keratinase production was done by initially sorting out the most influential factors (NaCl concentration, pH, inoculum level and incubation period in this study) through one factor at a time approach followed by central composite design based response surface methodology to enhance the keratinase production. Under optimized levels of NaCl (0.55 g/L), pH (7.35), inoculum level (5%) and incubation period (84 h), the keratinase production was enhanced from 41.62 U/mL to 401.67 ± 9.23 U/mL (9.65 fold increase) that corresponds to a feather degradation of 32.67 ± 1.36% was achieved. With regard to the cost effectiveness of application studies, the crude enzyme extracted from the optimized medium was tested for its potential dehairing, destaining and metal recovery properties. Complete dehairing was achieved within 48 h of treatment with crude enzyme without any visible damage to the collagen layer of goat skin. In destaining studies, combination of crude enzyme and detergent solution [1 mL detergent solution (5 mg/mL) and 1 mL crude enzyme] was found to be most effective in removing blood stains from cotton cloth. Silver recovery from used X-ray films was achieved within 6 min of treatment with crude enzyme maintained at 40 °C.

Contribution of household dishwashing to microplastic pollution.

At household level, clothes washing has been recognised as an emitter of microplastics (MPs) into the environment and it is supposed that dishwashing is also a source of MPs, although little attention has been paid so far. In this work, the emission of MPs released from dishwashing procedures at household level has been studied. The effect of different parameters such as time, temperature and type of detergent has been analysed. In addition, the MP content of tap water has been evaluated in order to determine its contribution to the MPs in dishwasher effluent. Results showed that when the dishwasher was operated empty with a pre-wash programme (15 min and room water temperature), between 207 and 427 MPs were released per load (3 L), whereas this value increased notably with an intensive programme (164 min and water at 70 °C) (1025-1370 MPs per load, 15 L), which highlighted the effect of temperature and time on MP release. Additionally, when a polypropylene lunch box was washed, the number of MPs released increased by 14 ± 3 MPs and 166 ± 12 MPs of total. Finally, the influence of the use of detergent with the dishwasher empty and containing lunch boxes has been studied. With detergent, 35-54% more MPs were released from dishwasher accessories, whereas no additional release took place from lunch boxes. This work shows for the first time the important contribution of domestic dishwashing to MP pollution and the environmental benefits of using more environmentally friendly materials in both dishwashing machine accessories and food utensils.

Facile and scalable fabrication of exosome-mimicking nanovesicles through PEGylated lipid detergent-aided cell extrusion.

We report a scalable fabrication method to generate exosome-mimicking nanovesicles (ENVs) by using a biocompatible, cell-binding lipid detergent during cell extrusion. A PEGylated mannosylerythritol lipid (MELPEG) detergent was rationally engineered to strongly associate with phospholipid membranes to increase cell membrane deformability and the corresponding friction force during extrusion and to enhance the dispersibility of ENVs. Compared to cell extrusion without detergent, cell extrusion in the presence of MELPEG increased the ENV production yield by approximately 20 times and cellular protein content per MELPEG-functionalized ENV by approximately 2-fold relative to that of unmodified ENVs. We verified that MELPEG strongly binds to ENV membranes and increases membrane deformability via expansion/swelling while preserving the integrity of the phospholipid bilayer structure. The results highlight that the MELPEG-aided cell extrusion process broadly applies to various cell lines; hence, it could be helpful in the production of ENVs for tissue regeneration, drug delivery, and cancer nanomedicine.

Prediction of methane per unit of dry matter intake in growing and finishing cattle from the ratio of dietary concentrations of starch to neutral detergent fiber alone or in combination with dietary concentration of ether extract.

Previous research demonstrated that a fixed value of 0.2433 (SE = 0.0134) Mcal of CH4/kg of dry matter intake (DMI) could be used to predict CH4 production with accuracy and precision on par with similar equations in the literature. Slope bias was substantially less for the fixed-coefficient equation than noted for the other DMI- or gross energy intake (GEI)-based equations, but mean bias was substantially greater, presumably reflecting the failure of the fixed-coefficient approach to account for dietary factors that affect CH4 production. In this article, we report on the use of the dietary ratio of concentrations of starch to neutral detergent fiber (NDF) and dietary ether extract (EE) concentration to improve the accuracy and precision of the fixed-coefficient equation. The same development data set used to create the fixed-coefficient equation was used in the present study, which included 134 treatment means from 34 respiration calorimetry studies. Based on stepwise regression with dietary NDF, starch, crude protein, EE, and the starch:NDF ratio as possible dependent variables, the starch:NDF ratio and EE were the only dietary variables selected (P ≤ 0.15). The study-adjusted relationship with the starch:NDF ratio (r2 = 0.673; root mean square error [RMSE] = 0.0327) was: Mcal of CH4/kg of DMI = 0.2883 - 0.03474 × starch:NDF; whereas the relationship with a model that included both starch:NDF ratio and dietary EE (r2 = 0.738; RMSE = 0.0315) was: Mcal of CH4/kg of DMI = 0.3227 - 0.0334 × starch:NDF - 0.00868 × % EE. A previously published independent data set with 129 treatment means from 30 respiration calorimetry studies was used to evaluate these two equations, along with two additional equations in which g/d of CH4 was predicted directly from DMI, starch:NDF ratio, and/or dietary EE. The two Mcal of CH4/kg of DMI equations had superior fit statistics to the previously published 0.2433 Mcal of CH4/kg of DMI equation, with a substantial decrease in mean bias and improved concordance correlation coefficients. Moreover, the Mcal of CH4/kg of DMI equations resulted in improved fit relative to direct prediction of g/d of CH4 from DMI, the starch:NDF ratio, and % EE. Based on these results, further evaluation of the dietary ratio of starch-to-NDF concentrations and EE concentration to predict methane production per unit DMI in beef cattle is warranted.

Accurate and precise equations to predict enteric methane production are an important tool as the beef industry works to mitigate greenhouse gas emissions. We predicted the megacalories of methane per unit of dry matter intake using data from growing and finishing beef and dairy steers and heifers. The predicted value was then multiplied by dry matter intake to estimate methane production. The most important predictor variables were the ratio of dietary starch to neutral detergent fiber concentrations and dietary ether extract concentration. When tested with an independent data set, predicting methane per unit dry matter intake from the ratio of starch to neutral detergent fiber, with or without the addition of dietary ether extract as a predictor variable, yielded better fits to the independent data set than equations in which the daily production of methane was predicted directly from dry matter intake, the ratio of starch to neutral detergent fiber, and/or dietary ether extract. Predictions could potentially be further refined by adjusting the starch component of the ratio for degradability in the rumen (e.g., degree of gelatinization or processing) and the neutral detergent fiber content for the contributions from roughage vs. grains and grain byproducts.

Development of a Cell-Based Biosensor for Residual Detergent Detection in Decellularized Scaffolds.

Ex vivo engineering of organs that uses decellularized whole organs as a scaffold with autologous stem cells is a potential alternative to traditional transplantation. However, one of the main challenges in this approach is preparing cytocompatible scaffolds. So far, high-precision and specific evaluation methods have not been developed for this purpose. Cell-based biosensors (CBBs) are promising tools to measure analytes with high sensitivity and specificity in a cost-effective and noninvasive manner. In this paper, using the NF-κB inducible promoter we developed a CBB for residual detergent detection. Proximal and core sections of the inducible promoter, containing NF-κB binding sequence, are designed and cloned upstream of the reporter gene (secreted alkaline phosphatase (SEAP)). After transfection into HEK293 cells, stable and reliable clones were selected. After confirmation of induction of this gene construct by sodium dodecyl sulfate (SDS), the stability and function of cells treated by qPCR and SEAP activity were measured. This biosensor was also used to evaluate the cytocompatibility of decellularized tissue. Results showed that the developed biosensor could detect very small amounts of SDS detergent (3.467 pM). It has the best performance 8 h after exposure to detergent, and its stability in high passage numbers was not significantly reduced. Applying this biosensor on decellularized tissues showed that SEAP activity higher than 4.36 (U/L) would lead to a viability reduction of transplanted cells below 70%. This paper presents a novel method to evaluate the cytocompatibility of decellularized tissues. The developed CBB can detect residual detergents (such as SDS) in tissues with high sensitivity and efficiency.

Distribution of Burkholderia cepacia complex species isolated from industrial processes and contaminated products in Argentina.

Burkholderia cepacia complex (Bcc) members have clinical relevance as opportunistic pathogens in patients with cystic fibrosis and are responsible of numerous nosocomial infections. These closely related bacteria are also reported as frequent contaminants of industrial products. In this retrospective study, we use PCR and recA gene sequence analysis to identify at species level Bcc isolates recovered from massive consumption products and industrial processes in Argentina during the last 25 years. The sequences obtained were also compared with recA sequences from clinical Bcc isolates deposited in GenBank database. We detected Bcc in purified water and preserved products from pharmaceutics, cosmetics, household cleaning articles, and beverages industries. B. contaminans (which is prevalent among people with cystic fibrosis in Argentina) was the most frequent Bcc species identified (42% of the Bcc isolates studied). B. cepacia (10%), B. cenocepacia (5%), B. vietnamiensis (16%), B. arboris (3%), and the recently defined B. aenigmatica (24%) were also detected. Rec A sequences from all B. cepacia and most B. contaminans industrial isolates obtained in this study displayed 100% identity with recA sequences from isolates infecting Argentinean patients. This information brings evidence for considering industrial massive consumption products as a potential source of Bcc infections. In addition, identification at species level in industrial microbiological laboratories is necessary for a better epidemiological surveillance. Particularly in Argentina, more studies are required in order to reveal the role of these products in the acquisition of B. contaminans infections.

Cognitive function among schoolchildren in Lebanon: association with maternal alcohol drinking and smoking during pregnancy and domestic use of detergents and pesticides during childhood.

To evaluate the relation between caregiver exposure to toxics during pregnancy and childhood and the child's cognitive function in Lebanese children. This was a cross-sectional study conducted on Lebanese students in public and private schools from November 2017 to May 2018, enrolling 464 children. A first linear regression, taking the Cattell total score as the dependent variable and taking sociodemographic characteristics and the family history of the child as independent variables, showed that higher age (Beta = 1.65) was significantly associated with higher cognition, whereas a history of eczema in any of the parents (Beta = -7.32) was significantly associated with lower cognition in the child. A second linear regression, taking the Cattell total score as the dependent variable and taking sociodemographic characteristics and the family history of the child, and the exposure to toxics as independent variables, showed that maternal alcohol intake during pregnancy (Beta = -1.07) and detergent mixing (Beta = -1.48) were significantly associated with lower cognition in the child. A third linear regression, taking the Cattell total score as the dependent variable and taking sociodemographic characteristics and the family history of the child, the exposure to toxics and the diseases in the child as independent variables, showed that maternal alcohol intake during pregnancy (Beta = -1.07) and detergent mixing (Beta = -1.45) were significantly associated with lower cognition in the child, whereas a history of eczema in the child before the age of 2 years (Beta = 8.72) was significantly associated with higher cognition in the child. This study is the first to examine the association of a child's prenatal exposure and their exposure during childhood to environmental toxicants with their cognitive function in Lebanon. We consider this study to be important as it shows the possible effect of cleaning products mixing and maternal alcohol consumption on cognitive functions among children in Lebanon.

[Simultaneous determination of 12 preservatives and antioxidants in fruit and vegetable detergents by gas chromatography-mass spectrometry].

A method was established for the simultaneous determination of 12 preservatives and antioxidants in fruit and vegetable detergents by gas chromatography-mass spectrometry (GC-MS). First, ethanol was added to remove the water in the sample by rotary evaporation and was extracted with acetonitrile in saturated n-hexane. Finally, the residual surfactant in the sample solution was removed with a saturated sodium chloride solution. The purified sample solution was concentrated and metered volume by acetonitrile. The preservatives and antioxidants were separated on a HP-5MS UI capillary column (30 m×0.25 mm×0.25 µm), and detected in the selective ion monitoring (SIM) mode. The method had a good linearity in the range of 0.1-10 mg/L with correlation coefficients (r2)>0.999, and the limits of detection (LODs) and limits of quantification (LOQs) were in the ranges of 0.010-0.030 mg/kg and 0.030-0.090 mg/kg, respectively. The recoveries of the 12 preservatives and antioxidants at three spiked levels (0.2, 2.0 and 10 mg/kg) were 68.3%-115.3% with the relative standard deviations (RSDs) of 3.1%-11.3%. (n=7) The method is sensitive and accurate, and can be suitable for the determination of preservatives and antioxidants in fruit and vegetable detergents.

Development of a ssDNA aptamer system with reduced graphene oxide (rGO) to detect nonylphenol ethoxylate in domestic detergent.

Endocrine-disrupting chemicals are a major public health problem throughout the world. In the human body, these compounds functionalize the same as sexual hormones, inducing precocious puberty, gynecomastia, etc. To help prevent this occurrence, a simple detection system is needed. In this study, a nonylphenol ethoxylate (NPE)-specific aptamer was selected by reduced graphene oxide-systematic evolution of ligands by exponential enrichment. A random ssDNA library was incubated with rGO for adsorption, followed by elution with the target molecule. As a result of screening, a DNA aptamer was found that specifically bounds to the target with high binding affinity (Kd  = 100.9 ± 13.2 nM) and had a low limit of detection (LOD = 696 pM). Furthermore, this NPE-binding aptamer bounds selectively to the target. Characterization of the aptamer was confirmed by measuring the fluorescence signal recovery from rGO. In addition, detection of NPE was performed with several water samples, and the detection accuracy was 100 ± 10%. From these results, we expect that this aptamer could be applied to an on-site detection system for NPE in industrial sites or domestic fields.

Identification of Poly(ethylene glycol) and Poly(ethylene glycol)-Based Detergents Using Peptide Search Engines.

Poly(ethylene glycol) (PEG) is one of the most common polymer contaminations in mass spectrometry (MS) samples. At present, the detection of PEG and other polymers relies largely on manual inspection of raw data, which is laborious and frequently difficult due to sample complexity and retention characteristics of polymer species in reversed-phase chromatography. We developed a new strategy for the automated identification of PEG molecules from tandem mass spectrometry (MS/MS) data using protein identification algorithms in combination with a database containing "PEG-proteins". Through definition of variable modifications, we extend the approach for the identification of commonly used PEG-based detergents. We exemplify the identification of different types of polymers by static nanoelectrospray tandem mass spectrometry (nanoESI-MS/MS) analysis of pure detergent solutions and data analysis using Mascot. Analysis of liquid chromatography-tandem mass spectrometry (LC-MS/MS) runs of a PEG-contaminated sample by Mascot identified 806 PEG spectra originating from four PEG species using a defined set of modifications covering PEG and common PEG-based detergents. Further characterization of the sample for unidentified PEG species using error-tolerant and mass-tolerant searches resulted in identification of 3409 and 3187 PEG-related MS/MS spectra, respectively. We further demonstrate the applicability of the strategy for Protein Pilot and MaxQuant.

A microbial identification framework for risk assessment.

Micro-organisms are increasingly used in a variety of products for commercial uses, including cleaning products. Such microbial-based cleaning products (MBCP) are represented as a more environmentally-friendly alternative to chemically based cleaning products. The identity of the micro-organisms formulated into these products is often considered confidential business information and is not revealed or it is only partly revealed (i.e., identification to the genus, not to the species). That paucity of information complicates the evaluation of the risk associated with their use. The accurate taxonomic identification of those micro-organisms is important so that a suitable risk assessment of the products can be conducted. To alleviate difficulties associated with adequate identification of micro-organisms in MBCP and other products containing micro-organisms, a microbial identification framework for risk assessment (MIFRA) has been elaborated. It serves to provide guidance on a polyphasic tiered approach, combining the data obtained from the use of various methods (i.e., polyphasic approach) combined with the sequential selection of the methods (i.e., tiered) to achieve a satisfactory identity of the micro-organism to an acceptable taxonomic level. The MIFRA is suitable in various risk assessment contexts for micro-organisms used in any commercial product.

Determining the Residual Characteristics of Alkylphenols, Arsenic, and Lead as well as Assessing the Exposures of 1,4-Dioxane from Household Food Detergents.

Food detergents are commonly used in households. The main components of detergents include surfactants and water. It has been found that certain compounds, which may cause health concerns, appear in food detergents, such as alkylphenols, arsenic, and lead. After applying food detergents is when people may be exposed to various levels of these chemicals when there are residues. In this study, the Taguchi experimental design was performed to determine the possible factors that might affect the residual characteristics of food detergent on dishware, fruits, and vegetables. The results showed that the variety of detergent was found to be the most significant factor affecting the residue amounts of arsenic (62.9%) and lead (71.6%) on fruits and vegetables, whereas the concentration of detergent used affected the amount of lead residue only (10.5%). On the other hand, dishware material, the concentration of analytes, immersion time, and type of surfactant contributed to arsenic residues on dishware, whereas technical nonylphenol isomer residues on dishware increased as the concentration of spiked analyte increased. In addition, the occurrence of 1,4-dioxane, a possible human carcinogen, in household food detergents in Taiwan was also determined in this research by solid-phase microextraction and GC-MS. Among the 80 detergent samples, 71 contained different concentrations ranges of 1,4-dioxane, from 0.03 to ~3.73 µg/g. In the exposure assessment, it was estimated that the maximum amounts of 1,4-dioxane in contact with the skin from the use of household food detergent in Taiwan was 0.015 µg/kg/day.

VOC exposures in California early childhood education environments.

Little information exists about exposures to volatile organic compounds (VOCs) in early childhood education (ECE) environments. We measured 38 VOCs in single-day air samples collected in 2010-2011 from 34 ECE facilities serving California children and evaluated potential health risks. We also examined unknown peaks in the GC/MS chromatographs for indoor samples and identified 119 of these compounds using mass spectral libraries. VOCs found in cleaning and personal care products had the highest indoor concentrations (d-limonene and decamethylcyclopentasiloxane [D5] medians: 33.1 and 51.4 µg/m³, respectively). If reflective of long-term averages, child exposures to benzene, chloroform, ethylbenzene, and naphthalene exceeded age-adjusted "safe harbor levels" based on California's Proposition 65 guidelines (10-5 lifetime cancer risk) in 71%, 38%, 56%, and 97% of facilities, respectively. For VOCs without health benchmarks, we used information from toxicological databases and quantitative structure-activity relationship models to assess potential health concerns and identified 12 VOCs that warrant additional evaluation, including a number of terpenes and fragrance compounds. While VOC levels in ECE facilities resemble those in school and home environments, mitigation strategies are warranted to reduce exposures. More research is needed to identify sources and health risks of many VOCs and to support outreach to improve air quality in ECE facilities.

Determinants of exposure to 2-butoxyethanol from cleaning tasks: a quasi-experimental study.

BACKGROUND: The quantitative assessment of airborne cleaning exposures requires numerous measurement methods, which are costly and difficult to apply in the workplace. Exposure determinants can be used to predict exposures but have yet to be investigated for cleaning activities. We identified determinants of exposure to 2-butoxyethanol (2-BE), a known respiratory irritant and suspected human carcinogen, commonly found in cleaning products. In addition, we investigated whether 2-BE exposures can be predicted from exposure determinants and total volatile organic compounds (TVOCs) measured with direct reading methods, which are easier to apply in field investigations. METHODS: Exposure determinants were studied in a quasi-experimental study design. Cleaning tasks were performed similarly as in the workplace, but potential factors that can impact exposures were controlled. Simultaneously for each task, we measured concentrations of (1) 2-BE according to the National Institute for Occupational Health and Safety 1430 method and (2) TVOC with photoionization detectors (PIDs). Simple and multiple linear regression analyses were performed to identify 2-BE exposure determinants and to develop exposure prediction models. RESULTS: Significant determinants from univariate analyses consisted of product type, tasks performed, room volume, and ventilation. The best-fit multivariable model was the one comprised of product type, tasks performed, 2-BE product concentration, room volume, and ventilation (R(2) = 77%). We found a strong correlation between the 2-BE and the TVOC concentrations recorded by the PID instruments. A multivariable model with TVOC explained a significant portion of the 2-BE concentrations (R(2) = 72%) when product type and room ventilation were included in the model. CONCLUSIONS: Our results suggest that quantitative exposure assessment for an epidemiologic investigation of cleaning health effects may be feasible even without performing integrated sampling and analytic measurements.

Reduction of Aeromonas hidrophyla biofilm on stainless stell surface by essential oils

This study demonstrates the possibility of using sanitizing detergents based on natural products for the elimination and/or reduction of Aeromonas hydrophila biofilm formed on stainless steel surfaces. The goal of this work was to determine the reduction effect of sanitizing detergents containing essential oils of Thymus vulgaris (thyme) and Cymbopogon citratus (lemongrass) on biofilm formed by A. hydrophila on AISI 304 stainless steel coupons, using UHT skimmed milk as substratum. There was adhesion and biofilm formation by A. hydrophila at 28 ºC, presenting 7.60 log cfu.cm-2 after the fourth day of cultivation. There was no significant difference between the lemongrass treatment and that of the thyme oil (p < 0.05). However, both treatments significantly reduced the biofilm, differing significantly from the NaOH control (p > 0.05). The treatment with lemongrass solution reduced the biofilm by 4.51 log cfu cm-2 at 25 ºC. The thyme detergent also reduced the number of cfu cm-2 by 3.84 log cycles at 25 ºC. The use of the lemongrass and thyme solutions efficiently reduced the A. hydrophila biofilm.

Ionic liquid-based dispersive liquid-liquid microextraction for the determination of formaldehyde in wastewaters and detergents.

Spectrophotometry in combination with ionic liquid-based dispersive liquid-liquid microextraction (DLLME) was applied for the extraction and determination of formaldehyde in real samples. The method is based on the reaction of formaldehyde with methyl acetoacetate in the presence of ammonia. The variation in the absorbance of the reaction product was measured at 375 nm. An appropriate mixture of ethanol (disperser solvent) and ionic liquid, 1-hexyl-3-methylimidazoliumhexafluoro-phosphate [C(6)MIM][PF(6)] (extraction solvent) was rapidly injected into a water sample containing formaldehyde. After extraction, sedimented phase was analyzed by spectrophotometry. Under the optimum conditions, the calibration graph was linear in the range of 0.1-20 ng mL(-1) with the detection limit of 0.02 ng mL(-1) and limit of quantification of 0.08 ng mL(-1) for formaldehyde. The relative standard deviation (RSD%, n = 5) for the extraction and determination of 0.8 ng mL(-1) of formaldehyde in the aqueous samples was 2.5%. The results showed that DLLME is a very simple, rapid, sensitive, and efficient analytical method for the determination of trace amounts of formaldehyde in wastewaters and detergents, and suitable results were obtained.

Under-estimation of self-reported occupational exposure by questionnaire in hospital workers.

OBJECTIVES: The aim of the study was to determine whether self-reported occupational exposure to cleaning/disinfecting agents in hospital workers is accurate, in comparison to expert assessment, taken to be the gold standard. METHODS: In the Epidemiological Study of the Genetics and Environment of Asthma (EGEA), participants were interviewed on occupation with a specific questionnaire for hospital workers regarding tasks and cleaning/disinfecting agents. Two estimates of exposure were available: self-report and expert assessment. The expert assessment involved a standardised procedure to estimate intensity, frequency and probability of exposure for each job. The present analysis focused on eight exposures: formaldehyde, glutaraldehyde, bleach/chlorine, alcohol, quaternary ammonium components, ammonia, sprays and latex gloves. Agreement and differences between self-reported and expert estimates were studied by kappa and phi coefficients and McNemar tests, respectively. RESULTS: In the survey of 1571 adults, 176 ever hospital workers (327 occupations) with both self-reported and expert exposure assessments were studied. An underestimation of self-reported exposure was observed especially for formaldehyde (26.5% vs 32.7%, p=0.01), ammonia (7.4% vs 18.8%, p<0.0001), alcohol (64.9% vs 93.0%, p<0.0001) and quaternary ammonium components (16.6% vs 70.9%, p<0.0001), compared to expert assessment. CONCLUSION: Occupational exposure to disinfecting/cleaning agents is common and high in hospitals. A large underestimation of self-reported exposure and a lack of knowledge of product components was observed. Our results show the relevance of expert assessment in epidemiological studies to limit measurement bias. This work underlines the need for health education programmes on the occupational risks induced by these types of products.