The Effects of Dry, Humid and Wear Conditions on the Antimicrobial Efficiency of Triclosan-Containing Surfaces

Subppb level monitoring and UV degradation of triclosan pollutants using ZnO multipod and Ag nanocomposites

A unique nanomaterial platform was developed for trace detection and efficient degradation of triclosan (TCS). A facile spectroscopic technique for surface-enhanced Raman scattering (SERS)-supported identification and ultraviolet (UV) degradation of TCS using a SERS template based on silver spherical nanoparticle (AgNP)-modified ZnO multipods (ZnO@Ag) is reported. Core-shell composite materials of ZnO multipods with a dimension of around 3 μm and AgNPs with an average diameter of ∼27 nm was designed not only as a substrate for TCS degradation up to ∼92% upon UV irradiation (λ = 365 mm, 300 μW/cm²) but also as a monitoring platform sensitive to TCS at a detection limit as low as 10^-9 M (≈0.3 ppb). Herein, the first investigation into ZnO@Ag bimetallic composites is established for both the SERS-based detection and UV-assisted degradation of environmental TCS pollutants. The calibration curve was estimated to be linear at R² > 0.97. The validated technology was successfully used to determine the antibacterial agent and TCS in distilled or river water. The advantages of the ZnO@Ag template are highlighted over conventional detection and excellent degradation.

The key to maximizing the benefits of antimicrobial and self-cleaning coatings is to fully determine their risks

Antimicrobial and self-cleaning nanomaterial coatings have attracted significant research attention in recent years due to the growing global threat of infectious diseases, the emergence of new diseases such as COVID-19, and increases in healthcare-associated infections. Although there are many reportedly successful coating technologies, the evaluation of antimicrobial performance is primarily conducted under simple laboratory conditions without adequate testing under real environmental conditions that reflect practical use and more importantly, reveal unintended outcomes. Furthermore, there is no standardized evaluation methodology to assess the long-term stability or the consequences associated with coating deterioration, such as the ecological impacts of nanomaterials or the proliferation of antibiotic-resistant bacteria/genes. In this review, we propose a precautionary framework that integrates a rigorous assessment of potential risks and limitations of nanomaterial coatings for antimicrobial applications as intrinsic to a comprehensive evaluation of their benefits. In addition, we summarize some emerging coating technologies as promising strategies to minimize unintended risks and enhance performance.

Listeria monocytogenes Biofilms in the Food Industry: Is the Current Hygiene Program Sufficient to Combat the Persistence of the Pathogen?

Biofilms contain microbial cells which are protected by a self-produced matrix and they firmly attach themselves to many different food industry surfaces. Due to this protection, microorganisms within biofilms are much more difficult to eradicate and therefore to control than suspended cells. A bacterium that tends to produce these structures and persist in food processing plants is Listeria monocytogenes. To this effect, many attempts have been made to develop control strategies to be applied in the food industry, although there seems to be no clear direction on how to manage the risk the bacteria poses. There is no standardized protocol that is applied equally to all food sectors, so the strategies for the control of this pathogen depend on the type of surface, the nature of the product, the conditions of the food industry environment, and indeed the budget. The food industry performs different preventive and corrective measures on possible L. monocytogenes-contaminated surfaces. However, a critical evaluation of the sanitization methods applied must be performed to discern whether the treatment can be effective in the long-term. This review will focus on currently used strategies to eliminate biofilms and control their formation in processing facilities in different food sectors (i.e., dairy, meat, fish, chilled vegetables, and ready-to-eat products). The technologies employed for their control will be exemplified and discussed with the objective of understanding how L. monocytogenes can be improved through food safety management systems.

Combined approaches for evaluation of xenoestrogen neural toxicity and thyroid dysfunction: Screening of oxido-nitrosative markers, DNA fragmentation, and biogenic amine degradation

Anthropogenic chemicals such as parabens and triclosan are used in personal care products. Due to their ability to decrease or prevent bacterial contamination and act as preservatives, these chemicals are used in cosmetic manufacturing processes to increase the shelf life of products. In this study, we assessed the side effects of environmental estrogens (such as the xenoestrogen butylparaben and the antimicrobial agent and preservative triclosan) on thyroid function, brain monoamine levels, and DNA aberration. Forty-two male albino rats were divided into seven groups with six members each: the first group served as control; the second and the third groups were treated with butylparaben 10 and 50 mg/kg body weight, respectively; the fourth and fifth groups were treated with triclosan 10 and 50 mg/kg body weight, respectively; and the sixth and seventh groups were treated with butylparaben plus triclosan 10 and 50 mg/kg body weight, respectively. After 60 days, blood samples were collected and brain specimens were divided into striatum, midbrain, cortex, and thalamus. Thyroid function and levels of monoamines and monoamine metabolites were determined for each brain area. Comet assay was used for brain tissue analysis. The results showed that butylparaben and triclosan and their combinations induced hypothyroidism and disrupted monoamine levels, leading to a decrease in catecholamine and serotonin levels, and accelerated production of 5-hydroxyindoleacetic acid. The obtained data indicate that anthropogenic chemicals such as butylparaben and triclosan have harmful effects on thyroid and brain function and accelerate cell destruction and mutation, as evidenced by single-stranded DNA breaks in the comet assay.

Antimicrobial Activity and Prevention of Bacterial Biofilm Formation of Silver and Zinc Oxide Nanoparticle-Containing Polyester Surfaces at Various Concentrations for Use

Food contact surfaces are primary sources of bacterial contamination in food industry processes. With the objective of preventing bacterial adhesion and biofilm formation on surfaces, this study evaluated the antimicrobial activity of silver (Ag-NPs) and zinc oxide (ZnO-NPs) nanoparticle-containing polyester surfaces (concentration range from 400 ppm to 850 ppm) using two kinds of bacteria, Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli), and the prevention of bacterial biofilm formation using the pathogen Listeria monocytogenes. The results of antimicrobial efficacy (reductions ≥ 2 log CFU/cm2) showed that at a concentration of 850 ppm, ZnO-NPs were effective against only E. coli (2.07 log CFU/cm2). However, a concentration of 400 ppm of Ag-NPs was effective against E. coli (4.90 log CFU/cm2) and S. aureus (3.84 log CFU/cm2). Furthermore, a combined concentration of 850 ppm Ag-NPs and 400 ppm ZnO-NPs showed high antimicrobial efficacy against E. coli (5.80 log CFU/cm2) and S. aureus (4.11 log CFU/cm2). The results also showed a high correlation between concentration levels and the bacterial activity of Ag-ZnO-NPs (R2 = 0.97 for S. aureus, and R2 = 0.99 for E. coli). They also showed that unlike individual action, the joint action of Ag-NPs and ZnO-NPs has high antimicrobial efficacy for both types of microorganisms. Moreover, Ag-NPs prevent the biofilm formation of L. monocytogenes in humid conditions of growth at concentrations of 500 ppm. Additional studies under different conditions are needed to test the durability of nanoparticle containing polyester surfaces with antimicrobial properties to optimize their use.