Contamination versus preservation of cosmetics: a review on legislation, usage, infections, and contact allergy

Lactoferrin and the lactoferrin-sophorolipids-assembly can be internalized by dermal fibroblasts and regulate gene expression

Lactoferrin (Lf) is an iron-binding multifunctional protein, mainly present in external secretions. Lf is known to penetrate skin and may thus exert its multiple functions in skin. Sophorolipids (SLs) are glycolipid biosurfactants, which have been shown to enhance absorption of commercial bovine Lf (CbLf) in model skin via forming an assembly with CbLf. In this study, uptake and post-internalization localization of bovine Lf (bLf), CbLf, and human Lf (hLf) with or without forming assemblies with SLs in human dermal fibroblasts (HDFn) were determined using ¹²⁵I-labeled Lfs and confocal microscopy, respectively. Our results show that all 3 Lfs were internalized by HDFn; although SLs did not significantly affect the uptake of Lfs, it changed Lf localization by accumulating Lfs in the perinuclear region. Furthermore, microarrays were used to investigate transcriptional profiling in HDFn in response to CbLf, SLs, or CbLf-SLs-assembly treatments. Transcriptome profiling indicates that CbLf may play roles in the protection of skin from oxidative stress, immunomodulatory activities, and enhancement of wound healing. The assembly had similar effects but dramatically modulated the transcription of some genes. SLs alone modified signaling pathways related to lipid metabolism, as well as synthesis of sex hormones and vitamins. Thus, CbLf may exert beneficial effects on skin, and these effects may be modulated by SLs.

Occurrence and concentrations of isothiazolinones in detergents and cosmetics in Switzerland

BACKGROUND

In recent years, the frequency of contact allergy to isothiazolinones has increased alarmingly in Europe, but only limited data are available on concentrations of isothiazolinones in consumer products.

OBJECTIVES

To examine the current frequency of isothiazolinones [methylisothiazolinone (MI), methylchloroisothiazolinone (MCI), benzisothiazolinone (BIT), and octylisothiazolinone (OIT)] in a wide array of detergents and cosmetics relevant for the Swiss population.

METHODS

By means of a market survey, the occurrence of isothiazolinones was investigated in 1948 consumer products. Of these, 88 products were analysed by liquid chromatography-high-resolution mass spectrometry after ultrasonic extraction.

RESULTS

Only 7.6% of all cosmetics contained isothiazolinones, but the prevalence in detergents was much higher (42.9%). The measured concentration ranges in detergents were 4.3–10, 3.5–279, 3.8–186 and 7.9 ppm (one product only) for MCI, MI, BIT, and OIT, respectively [corrected]. For cosmetics, these were 1.3-133 and 4.8 ppm (one product only) for MI and MCI, respectively.

CONCLUSIONS

Our study has shown that high concentrations of isothiazolinones (including MI) can be found in a large variety of products, in particular in detergents. Therefore, the safe use of these preservatives should be re-evaluated by including detergents in the exposure assessment.

Parabens abatement from surface waters by electrochemical advanced oxidation with boron doped diamond anodes

The removal efficiency of four commonly-used parabens by electrochemical advanced oxidation with boron-doped diamond anodes in two different aqueous matrices, namely ultrapure water and surface water from the Guadiana River, has been analyzed. Response surface methodology and a factorial, composite, central, orthogonal, and rotatable (FCCOR) statistical design of experiments have been used to optimize the process. The experimental results clearly show that the initial concentration of pollutants is the factor that influences the removal efficiency in a more remarkable manner in both aqueous matrices. As a rule, as the initial concentration of parabens increases, the removal efficiency decreases. The current density also affects the removal efficiency in a statistically significant manner in both aqueous matrices. In the water river aqueous matrix, a noticeable synergistic effect on the removal efficiency has been observed, probably due to the presence of chloride ions that increase the conductivity of the solution and contribute to the generation of strong secondary oxidant species such as chlorine or HClO/ClO ^-. The use of a statistical design of experiments made it possible to determine the optimal conditions necessary to achieve total removal of the four parabens in ultrapure and river water aqueous matrices.

Investigating incidence of bacterial and fungal contamination in shared cosmetic kits available in the women beauty salons

BACKGROUND

Rich texture of cosmetics can provide a suitable medium for growth of pathogenic microorganisms. In addition, skin microflora of anyone is unique which might be harmful to another person. Skin and eye pathogenicity could be communicated by sharing cosmetics in beauty saloons. The main objective of this study was to evaluate microbial contamination of in-use skin and eye cosmetics which are available as public make-up kits for women in the beauty salons.

METHODS

Fifty-two in-use skin and eye cosmetics were included in this cross sectional study.The specimens from all the cosmetics were collected following the owner's informed consent, and then about 1 g of the cosmetics was added to nine ml of liquid Eugon LT100 broth medium,two for each product. Ten beauty salons randomly selected from different regions of Tabriz city between June and August 2016. Cosmetics were sampled and carried to the laboratory in sterile condition and then examined to determine bacterial and fungal species in the samples.

RESULTS

All of in-use cosmetic were contaminated with bacteria (95% CI = 93.1%-100.0%) and about 19.2% by fungus and yeast (95% CI = 10.8%-31.9%). Streptococcus spp., Pseudomonas spp., Acinetobacter, Bacillus spp., Staphylococcus spp., Escherichia coli, Salmonella, Klebsiella,Citrobacter, Rhodotorula and Candida were dominant species which were isolated from the cosmetics. Powders with 38.5% (95% CI = 17.7%-64.5%) and eyeliners with 30.0% (95%CI = 6.7%-65.2%) were the most fungal contaminated products.

CONCLUSION

Shared cosmetics in beauty salons are almost contaminated by bacteria and fungus.Therefore, it is suggested to avoid sharing cosmetics by women and prevent use of public cosmetics in toilet saloons.

Cosmetics as endocrine disruptors: are they a health risk?

Exposure to chemicals from different sources in everyday life is widespread; one such source is the wide range of products listed under the title "cosmetics", including the different types of popular and widely-advertised sunscreens. Women are encouraged through advertising to buy into the myth of everlasting youth, and one of the most alarming consequences is in utero exposure to chemicals. The main route of exposure is the skin, but the main endpoint of exposure is endocrine disruption. This is due to many substances in cosmetics and sunscreens that have endocrine active properties which affect reproductive health but which also have other endpoints, such as cancer. Reducing the exposure to endocrine disruptors is framed not only in the context of the reduction of health risks, but is also significant against the background and rise of ethical consumerism, and the responsibility of the cosmetics industry in this respect. Although some plants show endocrine-disrupting activity, the use of well-selected natural products might reduce the use of synthetic chemicals. Instruments dealing with this problem include life-cycle analysis, eco-design, and green labels; in combination with the committed use of environmental management systems, they contribute to "corporate social responsibility".

Safe usage of cosmetics in Bangladesh: a quality perspective based on microbiological attributes

The present review attempted to emphasize on the microbiological quality of the commonly used cosmetics item by the majority of the Bangladeshi community. The abundance of contaminating microorganisms has been quantitatively discussed and the possible health risk has been focused upon usage of these items. Only a very few research efforts have been conducted on the cosmetic items in Bangladesh so far. The microbiological contamination aspects have been portrayed in this review using the information collected from a substantial number of cosmetic items which were earlier subjected to extensive microbiological and biochemical analyses. The prevalence of bacteria, fungi and the specific pathogenic microorganisms has been discussed based on research so far locally conducted on the finished items sold in markets, especially within the Dhaka metropolis. The laboratory scale experiments revealed the presence of enormous number of bacteria, actinomycetes and fungi within the commonly used cosmetics. Conversely, the anti-bacterial activity was noticed in some of the products which might be in favor of the user safety. The prevalence of pathogenic microorganisms in the cosmetic items certainly raises a substantial public health issue. The necessity of the routine microbiological testing of the commonly used cosmetic items as well as the legislative measures to mitigate the contamination problem is thus of great significance.

Effectiveness of five antidandruff cosmetic formulations against planktonic cells and biofilms of dermatophytes

This study aimed to investigate the in vitro antifungal effectiveness of five different formulations against dandruff and ringworm dermatophytes. Candida albicans was also included in our assays. Fungal susceptibility tests were performed with planktonic cells and biofilms of reference strains. Microbiological and physicochemical quality parameters were assessed for all formulations. Our data indicated that the formulations were effective against the dermatophytes strains, and to our knowledge, the effectiveness of cosmetic formulations against fungal biofilms is shown for the first time. The formulations were considered effective against the explored dermatophytes and were considered safe given the adequate microbiological and physicochemical characteristics shown in the proposed assays.

Preliminary safety assessment of C-8 xylitol monoester and xylitol phosphate esters

OBJECTIVES

Most of the cosmetic compounds with preservative properties available in the market pose some risks concerning safety, such as the possibility of causing sensitization. Due to the fact that there are few options, the proper development of new molecules with this purpose is needed. Xylitol is a natural sugar, and the antimicrobial properties of xylitol-derived compounds have already been described in the literature. C-8 xylitol monoester and xylitol phosphate esters may be useful for the development of skincare products. As an initial screen for safety of chemicals, the combination of in silico methods and in vitro testing can aid in prioritizing resources in toxicological investigations while reducing the ethical and monetary costs that are related to animal and human testing. This study was designed to evaluate the safety of C-8 xylitol monoester and xylitol phosphate esters regarding carcinogenicity, mutagenicity, skin and eye irritation/corrosion and sensitization through alternative methods.

METHODS

For the initial safety assessment, quantitative structure-activity relationship methodology was used. The prediction of the parameters carcinogenicity/mutagenicity, skin and eye irritation/corrosion and sensitization was generated from the chemical structure. The analysis also comprised physical-chemical properties, Cramer rules, threshold of toxicological concern and Michael reaction. In silico results of candidate molecules were compared to 19 compounds with preservative properties that are available in the market. Additionally, in vitro tests (Ames test for mutagenicity, cytotoxicity and phototoxicity tests and hen's egg test--chorioallantoic membrane for irritation) were performed to complement the evaluation.

RESULTS

In silico evaluation of both molecules presented no structural alerts related to eye and skin irritation, corrosion and sensitization, but some alerts for micronucleus and carcinogenicity were detected. However, by comparison, C-8 xylitol monoester, xylitol phosphate esters showed similar or better results than the compounds available in the market. Concerning experimental data, phototoxicity and mutagenicity results were negative. As expected for compounds with preservative activity, xylitol-derived substances presented positive result in cytotoxicity test. In hen's egg test, both molecules were irritants.

CONCLUSION

Our results suggested that xylitol-derived compounds appear to be suitable candidates for preservative systems in cosmetics.

A new protocol for evaluating the efficacy of some dispensing systems of a packaging in the microbial protection of water-based preservative-free cosmetic products

OBJECTIVE

A new protocol is described for assessing the efficacy of the dispenser of some packaging systems (PSs) of preservative-free cosmetic products in protecting both their contained formula and their delivered doses.

METHODS

Practically, aiming at mimicking contacts with a non-sterile skin or fingers, the dispensing system is put into contact with a pre-contaminated fabric by a standardized colonization of P. aeruginosa.

RESULTS

When applied to three different types of packaging, results show clear differences in both criteria between these conditioning articles, that is variable efficacies in protecting the contained product and the delivered doses, knowing that the first aspect is of paramount importance.

CONCLUSION

The proposed protocol is proved being able to discriminate between different PSs and provides information on strong and weak features of certain types dispensing technologies prone to efficiently decrease either the dose contamination or to prevent contamination in reaching the contained product. Therefore, the proposed protocol can contribute to an objective selection of a PS for protecting a cosmetic care product with a low content of preservative or preservative free.

Self-reported Lupus flare: Association with everyday home and personal product exposure

BACKGROUND

The number of chemicals in household products has driven concern about potential adverse health through their use. Most research concentrates on product chemicals with reproductive and carcinogenic consequences, however some evidence exists that immune effects can lead to exacerbation of autoimmune illnesses such as lupus (SLE).

OBJECTIVES

This paper examines household and personal product exposure patterns in a pilot case/control study of female Australians. We also examined associations between common product exposure and SLE symptom exacerbation over a year period.

METHODS

We enrolled 41 control and 80 SLE participants aged 18-80 years. Qualitative techniques of structured interview and thematic analysis retrospectively explored patterns of product use, and flare history data of SLE participants. Negative binomial regression models explored associations between self-reported flare (SRF) days and exposure to 34 common home product groups.

RESULTS

Mean product counts did not differ between participant groups (mean 33.1: SD 11.8), or flare groups (flare mean 32.6:SD 12, no-flare 31.8:SD 6.6). Products used for personal hygiene and general house cleaning were most frequently used.Significant association with increased SRF day relative risk (IRR) was seen for bath oil use (IRR 1.008, CI 1.00-1.02). Paradoxical "protective" effects, (reduced SRF days) were found for cleansing beauty (IRR 0.999, CI 0.998-0.999), make-up (IRR 0.998, CI 0.997-0.999); adhesives (IRR 0.994, CI 0.991-0.997) and paint (IRR 0.99, CI 0.986-0.995).

CONCLUSIONS

Everyday product exposures can impact on symptom exacerbation in SLE. Some offering protection and others increased health risk. Identifying environmental associations offer the possibility of life-style interventions to reduce illness impact.

Identification of didecyldimethylammonium salts and salicylic acid as antimicrobial compounds in commercial fermented radish kimchi

Daikon radish (Raphanus sativus) fermented with lactic acid bacteria, especially Leuconostoc or Lactobacillus spp., can be used to make kimchi, a traditional Korean fermented vegetable. Commercial Leuconostoc/radish root ferment filtrates are claimed to have broad spectrum antimicrobial activity. Leuconostoc kimchii fermentation products are patented as preservatives for cosmetics, and certain strains of this organism are reported to produce antimicrobial peptides (bacteriocins). We examined the antimicrobial agents in commercial Leuconostoc/radish root ferment filtrates. Both activity-guided fractionation with Amberlite XAD-16 and direct extraction with ethyl acetate gave salicylic acid as the primary agent with activity against Gram-negative bacteria. Further analysis of the ethyl acetate extract revealed that a didecyldimethylammonium salt was responsible for the Gram-positive activity. The structures of these compounds were confirmed by a combination of (1)H- and (13)C NMR, high-performance liquid chromatography, high-resolution mass spectrometry, and tandem mass spectrometry analyses. Radiocarbon dating indicates that neither compound is a fermentation product. No antimicrobial peptides were detected.

Occurrence and removal of transformation products of PPCPs and illicit drugs in wastewaters: a review

Pharmaceuticals and personal care products (PPCPs) along with illicit drugs (IDs) are newly recognized classes of environmental pollutants and are receiving considerable attention because of their environmental impacts: frequent occurrence, persistence and risk to aquatic life and humans. However, relatively little information is often available with regard to their possible biotic and abiotic transformation products (TPs). This lack of knowledge has resulted in a substantial amount of ongoing effort to develop methods and approaches that would assess their occurrence, degradability potential elimination mechanisms and efficiencies in sewage treatment plants as well as environmental and human health risks. In this article, an extensive literature survey was performed in order to present the current stage of knowledge and progress made in the occurrence of TPs of PPCPs and IDs in raw and treated wastewaters. Apart from the TPs resulting from structural transformations of the parent compound in the aquatic environment or in technological treatment facilities (e.g. sewage and drinking water treatment plants), free metabolites and drug conjugates formed during human metabolism have also been included in this review as they are also released into the aquatic environment through wastewaters. Their concentration levels were reported in influents and effluents of WWTPs, hospital effluents and their removals in the treatment plants were discussed. Finally, information on the toxicity of TPs has been compiled when available.

Bacillus cereus in personal care products: risk to consumers

Bacillus cereus is ubiquitous in nature and thus occurs naturally in a wide range of raw materials and foodstuffs. B. cereus spores are resistant to desiccation and heat and able to survive dry storage and cooking. Vegetative cells produce several toxins which on ingestion in sufficient numbers can cause vomiting and/or diarrhoea depending on the toxins produced. Gastrointestinal disease is commonly associated with reheated or inadequately cooked foods. In addition to being a rare cause of several acute infections (e.g. pneumonia and septicaemia), B. cereus can also cause localized infection of post-surgical or trauma wounds and is a rare but significant pathogen of the eye where it may result in severe endophthalmitis often leading to loss of vision. Key risk factors in such cases are trauma to the eye and retained contaminated intraocular foreign bodies. In addition, rare cases of B. cereus-associated keratitis (inflammation of the cornea) have been linked to contact lens use. Bacillus cereus is therefore a microbial contaminant that could adversely affect product safety of cosmetic and facial toiletries and pose a threat to the user if other key risk factors are also present. The infective dose in the human eye is unknown, but as few as 100 cfu has been reported to initiate infection in a susceptible animal model. However, we are not aware of any reports in the literature of B. cereus infections in any body site linked with use of personal care products. Low levels of B. cereus spores may on occasion be present in near-eye cosmetics, and these products have been used by consumers for many years. In addition, exposure to B. cereus is more likely to occur through other routes (e.g. dustborne contamination) due to its ubiquity and resistance properties of spores. The organism has been recovered from the eyes of healthy individuals. Therefore, although there may be a perceived hazard, the risk of severe eye infections as a consequence of exposure through contaminated near-eye cosmetics is judged to be vanishingly small. It is unlikely that more stringent microbiological standards for near-eye cosmetics will have any impact on the risk of severe eye infections caused by B. cereus, as these are not linked to use of personal care products.

Microbial quality survey of sunscreen products in Iranian market

Background:

Microbial contamination of cosmetic products is very crucial because of their daily use and direct contact with the skin. These products are at high risk for microbial contamination from various sources such as environment, consumer's hands, body sweat and during the time of manufacturing. Therefore, this study aimed to investigate the microbial quality of sunscreens products, manufactured in or imported to or formulated in local pharmacies in Iran.

Materials and Methods:

The microbial quality were determined in three different levels; the intact product (at the time of purchase) and after three and after six months of opening it. Total Aerobic Viable Count (TAVC) and the presence of coliforms, Pseudomonas aeruginosa, Staphylococcus aureus, molds, and yeasts were studied.

Results:

At the time of purchase, 40, 73.3 and 43.3 percentage of Iranian made, imported and pharmacy formulated sunscreens were contaminated with at least one of the objectionable microorganisms, respectively. After three months of opening it, 36.6, 70 and 46.6 percentage of Iranian made, imported and pharmacy formulated sunscreens were contaminated with at least one of the objectionable microorganisms, respectively. The percentages of contaminated samples were 36.6, 70 and 50 after six months of opening for Iranian made, imported and pharmacy formulated sunscreens, respectively.

Conclusion:

Microbial contamination of these sunscreens products is a potential health risk for consumers. It seems that it is necessary to inspect and monitor the products during the manufacturing and shelf life period. It is highly recommended to control and regulate cosmetic products by health organizations to ensure the quality and safety of this kind of products.

Ruthenium nanoparticles supported on CeO2 for catalytic permanganate oxidation of butylparaben

This study developed a heterogeneous catalytic permanganate oxidation system with ceria supported ruthenium, Ru/CeO2 (0.8‰ as Ru), as catalyst for the first time. The catalytic performance of Ru/CeO2 toward butylparaben (BP) oxidation by permanganate was strongly dependent on its dosage, pH, permanganate concentration and temperature. The presence of 1.0 g L(-1) Ru/CeO2 increased the oxidation rate of BP by permanganate at pH 4.0-8.0 by 3-96 times. The increase in Ru/CeO2 dosage led to a progressive enhancement in the oxidation rate of BP by permanganate at neutral pH. The XANES analysis revealed that (1) Ru was deposited on the surface of CeO2 as Ru(III); (2) Ru(III) was oxidized by permanganate to its higher oxidation state Ru(VI) and Ru(VII), which acted as the co-oxidants in BP oxidation; (3) Ru(VI) and Ru(VII) were reduced by BP to its initial state of Ru(III). Therefore, Ru/CeO2 acted as an electron shuttle in catalytic permanganate oxidation process. LC-MS/MS analysis implied that BP was initially attacked by permanganate or Ru(VI) and Ru(VII) at the aromatic ring, leading to the formation of various hydroxyl-substituted and ring-opening products. Ru/CeO2 could maintain its catalytic activity during the six successive runs. In conclusion, catalyzing permanganate oxidation with Ru/CeO2 is a promising technology for degrading phenolic pollutants in water treatment.

Solid lipid nanoparticles as effective reservoir systems for long-term preservation of multidose formulations

Cosmetic multidose preparations, as well as pharmaceutical ones, are at risk of contamination by microorganisms, due to their high water content. Besides the risk of contamination during manufacturing, multidose cosmetic preparations may be contaminated by consumers during their use. In this paper, the results of the utilization of nanoparticles as reservoir systems of parabens, the most used class of preservatives, were reported. Two different systems, solid lipid nanoparticles (SLN) made of pure precirol and nanostructured lipid carriers (NLC) made of precirol and almond oil, containing three parabens as single molecules or as a mixture, were prepared and tested. All the systems were characterized for size, polydispersion index, zeta potential and encapsulation efficiency. Release experiments, carried out in steady state and sink conditions, allowed to evidence that both SLN and NLC were able to act as reservoir systems. The antimicrobial activity of the systems was tested against Candida albicans ATCC 10231 with repeat insult tests. The results of the release experiments and the antimicrobial tests showed very low water concentration of parabens still maintaining their antimicrobial activity.

Investigation on the use of expired make-up and microbiological contamination of mascaras

OBJECTIVES

This study investigated the habits of female students regarding make-up use, and quantifies the microbiological contamination of mascaras worn by this population.

METHODS

To this end, 44 students answered a structured questionnaire to evaluate the use of expired make-up, shared usage and reports of adverse effects. Subsequently, make-up samples were collected to check the manufacturing registration and the expiration date and its visibility on the label. The total counts of microorganisms and identification of Pseudomonas aeruginosa and Staphylococcus aureus in mascara samples collected were performed as described in the Brazilian Pharmacopea (4th edition)

RESULTS

According to the results obtained, 97.9 % (43/44) of participants reported that they use or have previously used make-up after the expiration date, with mascara being the most frequently mentioned product. It was observed that on the sample collection date, 70.5% (31/44) of the students had some type of expired make-up. The microbiological analysis of 40 mascara samples revealed 2.54 ± 1.76 10(4)  UFC mL(-1) bacteria and 2.55 ± 1.54 10(4)  UFC mL(-1) fungi. Analysis revealed the presence of S. aureus in 79% of samples and of P. aeruginosa in 13%.

CONCLUSION

The results are interesting because they show that women tend to continue to use make-up beyond the expiry date. Frequently, these products have a high level of contamination with pathogenic microorganisms.

Methylparaben concentration in commercial Brazilian local anesthetics solutions

Objective

To detect the presence and concentration of methylparaben in cartridges of commercial Brazilian local anesthetics.

Material and methods

Twelve commercial brands (4 in glass and 8 in plastic cartridges) of local anesthetic solutions for use in dentistry were purchased from the Brazilian market and analyzed. Different lots of the commercial brands were obtained in different Brazilian cities (Piracicaba, Campinas and São Paulo). Separation was performed using high performance liquid chromatography (HPLC) with UV-Vis detector. The mobile phase used was acetonitrile:water (75:25 - v/v), pH 4.5, adjusted with acetic acid at a flow rate of 1.0 ml.min^-1.

Results

When detected in the solutions, the methylparaben concentration ranged from 0.01% (m/v) to 0.16% (m/v). One glass and all plastic cartridges presented methylparaben.

Conclusion

1. Methylparaben concentration varied among solutions from different manufacturers, and it was not indicated in the drug package inserts; 2. Since the presence of methylparaben in dental anesthetics is not regulated by the Brazilian National Health Surveillance Agency (ANVISA) and this substance could cause allergic reactions, it is important to alert dentists about its possible presence.

Formaldehyde in hair straightening products: rapid ¹H NMR determination and risk assessment

Despite official regulations, the illegal use of formaldehyde-containing or releasing hair straightening products has become a popular practice in Europe and high contents of formaldehyde in such products have been reported. In this study, a methodology utilizing (1)H NMR spectroscopy has been developed to measure the concentration of formaldehyde in hair straightening products. For sample preparation, a dilution and alkaline hydrolysis is required. The total formaldehyde content can then be quantified by a distinct peak of the CH2 group of the methanediol molecule in the δ4.84-4.82 ppm range. The developed methodology was applied for the analysis of 10 hair straightening products. Seven of these products contained detectable amounts of formaldehyde that were higher than the maximum allowed concentration of 0.2%. The formaldehyde content of these products was found to be in the range 0.42-5.83% with an average concentration of 1.46%. The accuracy and reliability of the NMR results were confirmed by the EU reference photometric method. The air formaldehyde concentrations after application of hair straightening products were estimated in ranges 20-423 ppm and 1-18 ppm (for 1 and 24 m(3) salon volume). A probabilistic exposure estimation using Monte Carlo simulation found the average formaldehyde concentration to be 6 ppm (standard deviation 15 ppm). All exposure scenarios considerably exceeded the safe level of 0.1 ppm. Our findings confirmed that the risk of cosmetic formulations with formaldehyde above 0.2% is not negligible, as these products may facilitate considerable exposure of formaldehyde for consumers especially for salon workers.

Blue light (470 nm) effectively inhibits bacterial and fungal growth

Blue light (470 nm) LED antimicrobial properties were studied alone against bacteria and with or without the food grade photosensitizer, erythrosine (ERY) against filamentous fungi. Leuconostoc mesenteroides (LM), Bacillus atrophaeus (BA) or Pseudomonas aeruginosa (PA) aliquots were exposed on nutrient agar plates to Array 1 (AR1, 0·2 mW cm(-2)) or Array 2 (AR2, 80 mW cm(-2)), which emitted impure or pure blue light (0-300 J cm(-2)), respectively. Inoculated control (room light only) plates were incubated (48 h) and colonies enumerated. The antifungal properties of blue light combined with ERY (11·4 and 22·8 μmol l(-1)) on Penicillium digitatum (PD) and Fusarium graminearum (FG) conidia were determined. Conidial controls consisted of: no light, room light-treated conidia and ERY plus room light. Light-treated (ERY + blue light) conidial samples were exposed only to AR2 (0-100 J cm(-2)), aliquots spread on potato dextrose agar plates, incubated (48 h, 30°C) and colonies counted. Blue light alone significantly reduced bacterial and FG viability. Combined with ERY, it significantly reduced PD viability. Blue light is lethal to bacteria and filamentous fungi although effectiveness is dependent on light purity, energy levels and microbial genus.

SIGNIFICANCE AND IMPACT OF THE STUDY

Light from two arrays of different blue LEDs significantly reduced bacterial (Leuconostoc mesenteroides, Bacillus atrophaeus and Pseudomonas aeruginosa) viabilities. Significant in vitro viability loss was observed for the filamentous fungi, Penicillium digitatum and Fusarium graminearum when exposed to pure blue light only plus a photosensitizer. F. graminearum viability was significantly reduced by blue light alone. Results suggest that (i) the amount of significant loss in bacterial viability observed for blue light that is pure or with traces of other wavelengths is genus dependent and (ii) depending on fungal genera, pure blue light is fungicidal with or without a photosensitizer.

Evaluation of the occurrence and biodegradation of parabens and halogenated by-products in wastewater by accurate-mass liquid chromatography-quadrupole-time-of-flight-mass spectrometry (LC-QTOF-MS)

An assessment of the sewage occurrence and biodegradability of seven parabens and three halogenated derivatives of methyl paraben (MeP) is presented. Several wastewater samples were collected at three different wastewater treatment plants (WWTPs) during April and May 2010, concentrated by solid-phase extraction (SPE) and analysed by liquid chromatography-electrospray-quadrupole-time-of-flight mass spectrometry (LC-QTOF-MS). The performance of the QTOF system proved to be comparable to triple-quadrupole instruments in terms of quantitative capabilities, with good linearity (R(2) > 0.99 in the 5-500 ng mL(-1) range), repeatability (RSD < 5.6%) and LODs (0.3-4.0 ng L(-1) after SPE). MeP and n-propyl paraben (n-PrP) were the most frequently detected and the most abundant analytes in raw wastewater (0.3-10 μg L(-1)), in accordance with the data displayed in the bibliography and reflecting their wider use in cosmetic formulations. Samples were also evaluated in search for potential halogenated by-products of parabens, formed as a result of their reaction with residual chlorine contained in tap water. Monochloro- and dichloro-methyl paraben (ClMeP and Cl(2)MeP) were found and quantified in raw wastewater at levels between 0.01 and 0.1 μg L(-1). Halogenated derivatives of n-PrP could not be quantified due to the lack of standards; nevertheless, the monochlorinated species (ClPrP) was identified in several samples from its accurate precursor and product ions mass/charge ratios (m/z). Removal efficiencies of parabens and MeP chlorinated by-products in WWTPs exceeded 90%, with the lowest percentages corresponding to the latter species. This trend was confirmed by an activated sludge biodegradation batch test, where non-halogenated parabens had half-lives lower than 4 days, whereas halogenated derivatives of MeP turned out to be more persistent, with up to 10 days of half-life in the case of dihalogenated derivatives. A further stability test performed with raw wastewater also showed that parabens degrade rapidly in real sewage, with half-lives lower than 10 h for n-butyl-paraben, while dihalogenated species again turned out to be more stable, with half-lives longer than a week.

Microbes in mascara: hypothesis-driven research in a nonmajor biology lab

In this laboratory exercise, students were taught concepts of microbiology and scientific process through an everyday activity - cosmetic use. The students' goals for the lab were to develop a hypothesis regarding microbial contamination in cosmetics, learn techniques to culture and differentiate microorganisms from cosmetics, and propose best practices in cosmetics use based on their findings. Prior to the lab, students took a pretest to assess their knowledge of scientific hypotheses, microbiology, and cosmetic safety. In the first week, students were introduced to microbiological concepts and methodologies, and cosmetic terminology and safety. Students completed a hypothesis-writing exercise before formulating and testing their own hypotheses regarding cosmetic contamination. Students provided a cosmetic of their own and, in consultation with their lab group, chose one product for testing. Samples were serially diluted and plated on a variety of selective media. In the second week, students analyzed their plates to determine the presence and diversity of microbes and if their hypotheses were supported. Students completed a worksheet of their results and were given a posttest to assess their knowledge. Average test scores improved from 5.2 (pretest) to 7.8 (posttest), with p-values < 0.0001. Seventy-nine percent (79%) of students correctly identified hypotheses that were not falsifiable or lacked variables, and 89% of students improved their scores on questions concerning safe cosmetic use. Ninety-one percent (91%) of students demonstrated increased knowledge of microbial concepts and methods. Based on our results, this lab is an easy, yet effective, way to enhance knowledge of scientific concepts for nonmajors, while maintaining relevance to everyday life.

Low-level efficacy of cosmetic preservatives

Preservation using combinations of preservatives has several advantages. This study shows that the concentration of some of the most frequently used allergenic preservatives can be markedly lowered when they are combined with phenoxyethanol. The antimicrobial efficacy of cosmetic preservatives and known allergens of various potency [diazolidinyl urea, methylchloroisothiazolinone/methylisothiazolinone (MCI/MI), methylisothiazolinone (MI) and phenoxyethanol] was tested alone and in various combinations of two or three preservatives together. The preservatives were tested for minimum inhibitory concentration (MIC) values and possible synergy using fractional inhibitory concentration. MCI/MI was the only preservative showing low-level MIC against all four tested microorganisms: Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger. Different combinations of the preservatives indicated additive effects against the microorganisms. No combination of preservatives showed any inhibitory action on each other. Challenge tests with different concentrations and combinations were performed in a cosmetic cream. Diazolidinyl urea and MCI/MI alone were ineffective against C. albicans in a challenge test at concentrations up to 16 times higher than the observed MIC values. When combining phenoxyethanol with either one of the allergenic preservatives diazolidinyl urea, MCI/MI or MI, the cosmetic cream was adequately preserved at concentrations well below the preservatives' MIC values as well as 10-20 times below the maximum permitted concentrations. By using combinations of preservatives, effective preservation can be achieved with lower concentrations of allergenic preservatives.