Search Results (36)

The long-term reliability of catalytic gas sensors is strongly influenced by changes in the chemical state and cleanliness of the catalyst surface. In this work, we investigate the surface composition and stability of the platinum (Pt) nanoparticle catalytic layer in Gas Metal-Oxide-Semiconductor (GMOS) sensors under varying environmental conditions. Using X-ray Photoelectron Spectroscopy (XPS) and High-Resolution (HR) XPS, we compared fresh, aged samples, thermally treated samples, and samples stored with or without a mechanical filter. The results show that prolonged ambient storage leads to the accumulation of adventitious carbon and nitrogen-containing species, as well as partial oxidation of platinum, which reduces the number of active metallic Pt sites. Thermal treatment at 300 °C for 30 min restores metallic Pt exposure by removing surface contaminants and narrowing the Pt 4f peaks. However, recontamination occurs during subsequent storage, with significant differences depending on surface protection. Sensors equipped with a mechanical filter exhibited obvious Pt metallic peaks in HR-XPS analysis, with lower carbon and nitrogen levels, compared to unprotected samples. These findings demonstrate that while heating refreshes catalytic activity, long-term stability requires complementary filtration to prevent re-adsorption of airborne species. The combined approach of heating and filtration is thus essential to ensure reliable performance of GMOS sensors for indoor and outdoor air quality monitoring. Full article

This study proposed a biosafe strategy to prevent staphylococcal enterotoxin production in cooked bacon, particularly in microenvironments at the product–package interface that may favor toxinogenesis. Challenge tests were conducted on bacon samples with varying water activity, inoculated with Staphylococcus aureus, and treated with a biopreservative produced in an axenic cultivation of Lacticaseibacillus paracasei DTA-83. Staphylococcal enterotoxin production was assessed using an ELISA test. Data about microbial growth and staphylococcal enterotoxin production were evaluated under simulated storage using the MicroLab_ShelfLife protocol. Results showed that staphylococcal enterotoxin production occurred independently of water activity, indicating that it alone does not ensure microbial safety. Even at a water activity level traditionally considered inhibitory, enterotoxin formation was observed, emphasizing the critical role of the product–package interface. However, a 1.0% biopreservative applied to the product surface effectively inhibited S. aureus growth and completely suppressed staphylococcal enterotoxin production under all conditions, including temperature abuse. In conclusion, the formation of enterotoxin by S. aureus at low water activity reveals a critical safety risk at the product–package interface. Targeted application of a 1.0% biopreservative at this vulnerable site proved highly effective, reinforcing its role as a practical and non-intrusive hurdle strategy to enhance microbial safety in shelf-stable meat products. Full article

Polychlorinated biphenyls (PCBs) are synthetic organic compounds that were widely used in industrial applications throughout the 20th century. Due to their chemical stability, resistance to degradation and ability to bioaccumulate and biomagnify through food chains, PCBs pose long-term environmental and health risks. Due to these characteristics, PCBs have been globally regulated as persistent organic pollutants (POPs), despite being banned from production in most countries decades ago. This study investigates temporal trends in PCB contamination in urban soils of Bucharest over a 20-year period (2002–2022), focusing on six principal congeners (PCB 28, 52, 101, 138, 153, and 180) sampled from 13 locations, including roadsides and urban parks. Gas chromatography and spatial analysis using inverse distance weighting (IDW) revealed a marked reduction in Σ6PCB concentrations, declining from 0.0159 mg/kg in 2002 to 0.0065 mg/kg in 2022, with statistically significant differences confirmed by Kruskal–Wallis analysis (p < 0.05). This decline is primarily attributed to reduced emissions, source control measures, and natural attenuation. However, the persistence of PCBs in localized hotspots is influenced by secondary dispersion mechanisms, such as atmospheric deposition and surface runoff, which redistribute contaminants rather than eliminate them. Health risk assessments via ingestion, dermal absorption, and inhalation routes confirmed negligible carcinogenic risk for both adults and children. Although measurable progress has been achieved, the persistence of localized contamination underscores the need for targeted remediation strategies and sustained environmental monitoring to protect vulnerable urban areas from recontamination. Full article

Every year, 48 million people in the United States are affected by foodborne illnesses. Twenty-five percent of reported foodborne illnesses are due to unsafe food behaviors in the home. Consumers are grilling more frequently throughout the year; however, little is known about their food handling practices when doing so. Therefore, it is important to investigate the food safety practices of consumers when using an outdoor grill to prepare meat and poultry. A nationwide web survey of consumers who grill outdoors (n = 1024) was conducted to approximate the percentage of consumers following recommended food handling practices while grilling. Results showed that there was low adherence to not washing meat/poultry, using separate or clean utensils after flipping or turning the meat or poultry on the grill, or using a thermometer to determine doneness. Sixty-three percent of respondents washed meat or poultry before grilling. Only 22% reported washing utensils after turning or moving the poultry or meat on the grill, which can cause potential cross- or re-contamination. Consumers used many techniques to determine the doneness of meat/poultry, but only 25.6% used a thermometer. The results differed by some demographic characteristics. Women and respondents who grilled poultry versus meat were more likely to follow safe food handling practices. This survey indicates that food safety educators should focus strongly on cross- or re-contamination and thermometer use when designing food safety content for the grilling population. Full article

Background and Objectives: Endodontic success depends on eliminating infection and creating a durable seal to prevent recontamination. The goal of this study was to assess the impact of different ISO sizes on the obturation quality using two reciprocating single-file systems, WaveOne^® Gold and Procodile^®, in two different canal morphologies. Material and Methods: Overall, 140 root canals from human permanent teeth were randomly assigned to 14 groups based on selected ISO sizes and straight and curved canal curvatures, and the two file systems, WaveOne^® Gold files in ISO sizes 20, 25, and 45, and Procodile^® files in ISO sizes 20, 25, 40, and 45, were employed for canal preparation. These 140 canals were obturated using corresponding gutta-percha points and AH-Plus sealer and the quality of the obturation was assessed after sectioning the roots (apical, middle, coronal third) by evaluating the resulting 420 sections under a digital fluorescence microscope with regard to the proportion of gutta-percha, sealer, and unfilled areas. The results were analyzed using nonparametric tests. Results: For both systems, there was a significant difference in the percentage of gutta-percha-filled areas (PGFA, p < 0.001) and sealer-filled areas (PSFA, p < 0.001 among the different ISO sizes). However, no significant difference was observed in the percentage of unfilled areas (PUA, p = 0.354). ISO 40 demonstrated the best results, with the highest percentage of gutta-percha-filled areas (87%) and the lowest percentages of sealer-filled areas (13%) and voids (0.5%). In contrast, the lowest percentages of gutta-percha filled areas were observed in root canal fillings with ISO 20 (81%) and ISO 25 (81%). Regarding both reciprocating file system sizes, ISO 45 in WaveOne^® Gold and ISO 40 in Procodile^® demonstrated significantly improved (p < 0.05) filling quality, with PGFA of 85% and 87%, respectively. The differences between both systems were not significant. Conclusions: The results presented suggest that larger sizes provide better filling results, especially in the apical region. These results underline the importance of selecting appropriate preparation sizes adjusted to the initial anatomical specifications to optimize root canal obturation and ensure a high quality and durable seal. Full article

Background/Objectives: In healthcare environments with high microbial loads, effective infection control measures are critical for reducing airborne and surface contamination. One of the novel modalities in the achievement of these goals is the use of antimicrobial mists, such as droplets, in the form of dry fog. Although the usage of dry fog in the disinfection of contained healthcare microenvironments is well known, the effect of such a system in terms of a meaningful reduction in the microbial burden in an open inpatient ward is unclear. Our objective was to assess the impact of scheduled dry fogging on microbial reduction in such settings. Methods: We collected air and surface samples from rooms receiving daily, biweekly, or no fogging (controls) over six months, establishing the baseline contamination and evaluating the reduction trends in treated rooms. The “reduction effect” was measured by tracking microbial isolation trends before and after treatment, while the “degree of reduction” assessed differences across rooms with varied disinfection schedules. Results: The results indicate that scheduled dry fogging significantly reduced microbial loads in treated rooms, especially with daily disinfection (SE = 64.484, p = 0.002). The airborne contamination in treated rooms showed a strong downward trend over time (SE = 19.192, p < 0.001). Surface contamination remained challenging due to frequent recontamination; however, treated rooms exhibited a consistent reduction in microbial presence (SE = 2.002, p = 0.010), confirming dry fogging’s role as a valuable adjunct to routine cleaning. Conclusions: In conclusion, this study highlights that dry fogging effectively reduces microbial loads in open, high-traffic healthcare environments, supporting its use as part of a multimodal infection control strategy. Full article

A quantitative risk assessment (QRA) model was developed to evaluate the risk of invasive listeriosis from the consumption of non-ready-to-eat (non-RTE) frozen vegetables. On a lot basis, the QRA model simulates Listeria monocytogenes concentration and prevalence in a “Processing module” that comprises blanching, potential recontamination and packaging, any post-packaging inactivation treatment, and within-lot end-product testing and in a subsequent “Consumer’s handling module” that encompasses portioning of frozen vegetables, defrosting, and cooking. Based on available published data, the model was coded in nine sequential R functions designed to assess the effectiveness of blanching, the improvement in processing environment hygiene, the implementation of sampling schemes at the end of processing, and improved consumer instructions on the product’s package. In a reference scenario, the model estimated that 9.4% of 500 g packages of frozen vegetables would be contaminated, although at mean levels lower than 10 CFU/g, and assuming that 20% of the portions of frozen vegetables would be left to thaw at room temperature for 2 h, the lot-level mean risk of listeriosis in the susceptible population would be 2.935 × 10⁻¹⁴ (median 5.446 × 10⁻¹⁵) for uncooked 50 g servings and 2.765 × 10⁻¹⁷ (median 5.184 × 10⁻¹⁸) for cooked 50 g servings. Analysis of selected scenarios suggested that not cooking the non-RTE product contributes to the risk to a greater extent than the level of contamination in the incoming raw vegetables, the latter in turn being more influential than the level of contamination in the processing environment. The QRA model is freely available as an R package with full documentation and can be used as a tool to inform the consideration of strengthened risk management measures in view of the current changes in consumer behavior and new diet trends. Full article

In communities where people lack on-demand, safely managed drinking water, stored household water often becomes contaminated by fecal bacteria, regardless of the source-water quality. The objectives of this paper are to assess and control bacterial contamination in stored household water in Toamasina, a rapidly urbanizing city in eastern coastal Madagascar. We collected samples of source water and stored household water from 10 representative households that use different water sources and different storage strategies, and we analyzed the samples for several fecal indicator bacteria. We also tested three methods that residents of Toamasina could realistically employ for cleaning their household water storage vessels, assessing the effect of the cleaning methods on measured bacterial levels in the water. Consistent with the previous literature, we found that concentrations of total coliforms in stored household water were significantly higher than in the corresponding source water (p < 0.05). In 100% of households that stored their water in 20 L polyethylene jerrycans (n = 4), biofilms on the walls of the jerrycan harbored total coliforms and Enterococcus. The use of a closed storage container was, on its own, not found to provide a meaningful protective effect against bacterial regrowth; to be protective, closed storage containers must be combined with high-quality source water and/or with adequate cleaning to prevent biofilm formation. A dilute solution of sodium hypochlorite, known locally as Sûr’Eau or Manadio Rano, was both the most effective and the least expensive method for cleaning household water storage containers. We conclude that regular and effective cleaning of storage containers is an essential component of safe water storage. Because household storage of collected water is common in many low- and middle-income countries, these results are important towards the worldwide achievement of the United Nations’ Sustainable Development Goal 6. Full article

A review of the published quantitative risk assessment (QRA) models of L. monocytogenes in dairy products was undertaken in order to identify and appraise the relative effectiveness of control measures and intervention strategies implemented at primary production, processing, retail, and consumer practices. A systematic literature search retrieved 18 QRA models, most of them (9) investigated raw and pasteurized milk cheeses, with the majority covering long supply chains (4 farm-to-table and 3 processing-to-table scopes). On-farm contamination sources, either from shedding animals or from the broad environment, have been demonstrated by different QRA models to impact the risk of listeriosis, in particular for raw milk cheeses. Through scenarios and sensitivity analysis, QRA models demonstrated the importance of the modeled growth rate and lag phase duration and showed that the risk contribution of consumers’ practices is greater than in retail conditions. Storage temperature was proven to be more determinant of the final risk than storage time. Despite the pathogen’s known ability to reside in damp spots or niches, re-contamination and/or cross-contamination were modeled in only two QRA studies. Future QRA models in dairy products should entail the full farm-to-table scope, should represent cross-contamination and the use of novel technologies, and should estimate L. monocytogenes growth more accurately by means of better-informed kinetic parameters and realistic time–temperature trajectories. Full article

Toxocara spp. is a zoonotic soil-transmitted parasite that infects canids and felids, which causes toxocariasis in humans, migrating to organ systems, including the lungs, the ocular system, and the central nervous system. Since Toxocara spp. is usually transmitted through soil, children tend to be more susceptible to infection. In order to monitor contamination with Toxocara spp. in children’s play facilities in the Republic of Korea, we investigated 11,429 samples of soil from daycare centers, kindergartens, elementary schools, and parks across the country from January 2016 to December 2021. Since the Environmental Health Act in the Republic of Korea was enacted in March 2008, there have been sporadic reports of contamination by Toxocara spp. in children’s activity zones. In this study, soil from children’s play facilities in regions across the Republic of Korea was monitored according to the Korean standardized procedure to use it as basic data for preventive management and public health promotion. The national average positive rate was 0.16% (18/11,429), and Seoul showed a higher rate of 0.63% (2/318) than any other regions while Incheon, Daegu, Ulsan, Kangwon-do, Jeollabuk-do, and Jeollanam-do were negative (p < 0.05). The positive rates were as follows: 0.37% (4/1089) in daycare centers, 0.13% (3/2365) in kindergartens, 0.2% (7/4193) in elementary schools, 0.09% (1/1143) in apartments, and 0.14% (3/2198) in parks. In addition, it was confirmed that 0.2% (1/498) of elementary schools and 1.17% (2/171) of parks were re-contaminated among play facilities managed with the establishment of a regular inspection cycle. Consequently, there is an essential need for continuous monitoring of Toxocara spp. contamination and regular education for preschool and school children in order to prevent soil-borne parasite infections. Full article

The use of conventional chemical disinfectants is a common practice in built environments and has drastically increased in response to the COVID-19 pandemic. While effective for instantaneous disinfection, the application of chemical disinfectants to indoor surfaces is associated with recontamination and is prone to select for antimicrobial-resistant pathogens. In contrast, probiotic-based sanitation (PBS) relies on the premise that probiotic bacteria, namely apathogenic Bacillus spp., when combined with eco-friendly detergents and applied to indoor surfaces can outcompete and exclude pathogens. Recent in situ studies assessing PBS in healthcare settings have demonstrated overwhelmingly positive results, including significant reductions in pathogen burden, antimicrobial-resistant genes and nosocomial infections, yet these studies are limited in duration and scope. Here, we review results of Bacillus-based PBS in practice, identify knowledge gaps and discuss the considerations for the widespread use of PBS in built environments. In a time when indoor cleaning and disinfection has come to the forefront, PBS may offer an attractive, effective and sustainable alternative to conventional chemical disinfectants. Full article

Pinworm ova were discovered on lesser hedgehog tenrec (Echinops telfairi) fecal exams. Ova were passthrough pseudoparasite pinworms originating from feeder roaches (Blaptica dubia). Roaches were maintained as a feeder colony and offered to tenrecs as a portion of their diet. Pinworms were identified as Leidynema appendiculata. This study aimed to determine if these pinworms could be eliminated from the roaches. Roaches were randomly assigned into groups (n = 24), including a control (A) and four treatment groups (B–E). Treatment group roaches received oral dosing of anthelmintic pyrantel pamoate at four concentrations (mg/g as offered): 3.5 (Group B), 14.0 (Group C), 26.0 (Group D), and 35.0 (Group E). Roach diets were made weekly and offered to roaches 2 consecutive days per week for 3 consecutive weeks. The total pinworm ova per gram of roach feces examined were visually reduced in all treatment groups compared to controls at the end of the feed dosing period (Day 23). Post-treatment pinworm numbers were visually reduced in all treatment groups compared to controls on Day 29 and Day 65. Groups receiving higher concentrations of the oral dosing (C–E) significantly differed from controls at Day 29 (p = 0.0086, p = 0.0045, and p = 0.0013, respectively) with a concentration-dependent response. Parasites were not eliminated in any group at Day 29 or 65 post-treatment, with an increasing visual trend indicating recontamination. This is the first report confirming a passthrough pseudoparasite in tenrecs from dubia roaches, and anthelmintic dosage research is warranted. Full article

Many publications report coatings that exhibit antimicrobial potency applicable to high-touch surfaces and desirable for healthcare settings to contribute to reductions in the occurrence of Hospital Acquired Infections (HAI). In this review, the importance of surface contamination and the transmission of microbes is addressed. The standard strategy to tackle fomites is to implement proper disinfection and cleaning practices and periodically monitor the environment’s cleanliness. However, the probability of recontamination of cleaned surfaces is high. Therefore, an additional first line of defense against pathogen transmission and subsequent infection is the antimicrobial surface that can eliminate or at least repel pathogens, introducing a barrier to the spread of infection. It is a simple concept, but formulating a durable, antimicrobial coating with broad-spectrum antimicrobial and antifouling activities has proven challenging. The challenges and progress made in developing such material are reviewed. Full article

Animal feed production is an important step of the food animal production chain in a farm-to-table model. The contamination of raw ingredients with foodborne pathogens in feed production remains as an important safety issue where pathogens may spread into food animals to cause illnesses in humans when affected food animals are consumed. In the present study, we aimed to examine the quality and microbial contamination of fish meal and to investigate the effectiveness of the organic acid-based antimicrobial agent SALTEC 514^TM against Salmonella to prevent bacterial contamination in fish meal. Fish meal samples (n = 4) collected from feed mills at different locations were analyzed for protein and total volatile basic nitrogen (TVBN) content to assess their nutritional value and freshness, and its microbiological quality. The protein and TVBN content ranged from 53.2 ± 3.1 to 67.5 ± 2.3 g/100 g and 73.8 ± 4.5 to 100.4 ± 11.2 mg/100 g meal, respectively. Total plate count of the fish meal samples ranged from 2.0 ± 0.3 to 4.5 ± 0.5 log units, whereas suspected foodborne bacteria, Escherichia coli and Salmonella, were not detected in all samples. Fish meal samples were artificially contaminated (day 0) and re-challenged (day 30 and 90) with Salmonella Enteritidis (3 log CFU/g) to test for the effectiveness of SALTEC 514^TM, an organic acid-based antimicrobial formulation, in preventing Salmonella contamination and recontamination during storage. SALTEC 514^TM, when applied at three different doses, was found to reduce the number of Salmonella in monitored samples after one day of storage. A low dose of 0.5 kg/ton SALTEC 514^TM prevented Salmonella recontamination from occurring in fish meal samples stored for 37 days. In medium (1.0 kg/ton) and high doses (3.0 kg/ton), applications of SALTEC 514^TM prevented the Salmonella recontamination for a maximum storage duration of 97 days. The application of SALTEC 514^TM in fish meal and/or other feed ingredients may prove to be a safe alternative to reduce the microbial load, especially of foodborne-related microorganisms, to contribute to feed and food safety. Full article

In–situ cleaning of the substrate surface by ion etching is an integral part of all physical vapor deposition (PVD) processes. However, in industrial deposition systems, some side effects occur during the ion etching process that can cause re-contamination. For example, in a magnetron sputtering system with several sputter sources and with a substrate holder located centered between them, the ion etching causes the contamination of the unshielded target surfaces with the batching material. In the initial stage of deposition, this material is redeposited back on the substrate surface. The identification of the contamination layer at the substrate–coating interface is difficult because it contains both substrate and coating elements. To avoid this problem, we prepared a TiAlN double coating in two separate production batches on the same substrate. In such a double-layer TiAlN hard coating, the contamination layer, formed during the ion etching before the second deposition, is readily identifiable, and analysis of its chemical composition is easy. Contamination of the batching material was observed also on seed particles that caused the formation of nodular defects. We explain the origin of these particles and the mechanism of their transfer from the target surface to the substrate surface. By comparison of the same coating surface area after deposition of the first and second TiAlN layers, the changes in coating topography were analyzed. We also found that after the deposition of the second TiAlN coating, the surface roughness slightly decreased, which we explain by the planarization effect. Full article