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- Community-Based Pilot Study of Chlamydia trachomatis and Neisseria gonorrhoeae Urogenital Infections Among Young Adults in the North and the Central Coast of PortugalPublication . Rodrigues, Rafaela; Loureiro, Sónia; João, Inês; Jordão, Inês; Borrego, Maria José; Catalão, Carlos; Silva, Ana Rita; Sousa, Carlos; Vale, NunoBackground and Objectives: Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) are among the most common sexually transmitted infections (STIs), with the highest incidence in individuals aged up to 25 years. However, data from Portugal remain scarce. This cross-sectional pilot study aimed to assess the prevalence of urogenital CT and NG infections in young adults in Portugal and to identify the major CT genotypes circulating in this population. Materials and Methods: A total of 152 young adults aged 18-25 years were recruited over a six-month period from universities, a sports club, and a coworking space. Urine samples were tested using the Cobas 4800 CT/NG assay (Roche, Rotkreuz, Switzerland). CT-positive samples were further genotyped based on ompA gene diversity to identify major urogenital genotypes (D to K). All participants provided informed consent and completed a questionnaire on demographic characteristics and risk behaviors. Results: Of the 152 urine samples analyzed, five tested positive for CT, one for NG, and one sample showed co-infection with both pathogens. None of the participants with positive results reported symptoms. Genotyping of CT-positive samples identified ompA genotype E in three cases. Conclusions: Despite limitations such as small sample size and convenience sampling, this pilot study offers preliminary insights into the prevalence and genetic diversity of CT and NG infections among young adults in Portugal. The findings highlight the need for expanded screening programs, site-specific sample collection, and culture-based diagnostics to support evidence-based public health strategies targeting these infections.
- Method validation for the determination of total mercury in foodstuffs by direct mercury analysis (DMA)Publication . Nascimento, Ana C.; Santiago, Susana; Santos, MarianaMercury is a toxic metal that can be transformed by bacteria into methylmercury, a more harmful and bioavailable form, which accumulates in the food chain, particularly in fish and shellfish. Monitoring mercury levels is essential for ensuring food safety, especially to protect vulnerable groups, such as pregnant women, due to its potential impact on foetal development and neurological function. As it is well known, most of the total mercury present in aquatic food is in the form of methylmercury, which reinforces the importance of accurate and reliable analysis, as it's the form most concerning to human health. The purpose of this study was to validate a method for mercury measurements in food samples, to ensure its accuracy, reliability, and suitability for applications in food safety, quality control, and regulatory compliance. A method for total mercury determinations in food matrices was validated, using a Direct Mercury Analyser (DMA-80), based on thermal decomposition, amalgamation, and atomic absorption spectrometry (AAS). The validated method covers two calibration ranges: from 2.5-15 ng and 30-1000 ng, using two separate calibration curves. Trueness, repeatability and intermediate precision (within-laboratory precision) were assessed using a certified reference material (CRM), NIST 1566b Oyster Tissue, and through interlaboratory comparison tests. Trueness, repeatability, and intermediate precision showed uncertainty values of 11%, 5%, and 8%, respectively. The detection and quantification limits were determined as 0.0014 mg.Kg-1 and 0.0038 mg.Kg-1. These levels are significantly lower than the maximum levels stablished by Regulation (EU) 2023/915, which sets mercury limits of 0.1 mg.Kg-1for food supplements and salt, 0.3 or 0.5 mg.Kg-1 for most fish, molluscs and bivalves, and 1.0 mg.Kg-1 for large predatory fish. Quality control tools included blanks for contamination checks and two standards measured in each curve, during every experiment, to verify calibration accuracy. Additionally, CRMs must be within their established reference values, and interlaboratory test results must meet a z-score between -2 and 2 to be considered acceptable. In conclusion, the analysed method is rapid and precise, requires minimal sample preparation, and is suitable for several matrices, with low detection limits and strong analytical performance.
- Total Diet Studies: A comprehensive tool for dietary exposure assessmentPublication . Vasco, Elsa; Dias, Maria da Graça; Oliveira, LuísaIntroduction Total Diet Studies (TDS) are a cost-effective, scientifically robust approach recommended by the World Health Organization (WHO) to estimate long-term population exposure to dietary chemical contaminants. Unlike traditional monitoring, TDS analyses food- "as consumed," and considers the overall diet, offering realistic insights into chronic risks and supporting public health policy. Standardized methods, such as those from TDS-Exposure and EFSA/FAO/WHO, enhance data quality and cross-country comparability. Methodology The study involves two main sampling phases: planning and fieldwork, followed by chemical analysis of the TDS samples and subsequent exposure assessment and risk characterisation. During planning, key food items are selected based on national dietary data, classified using the FoodEx2 system, and organized into TDS samples. Sampling considers factors such as origin, market share, season, and cooking habits. In fieldwork, food samples are collected from retail outlets, prepared according to culinary practices, and combined into composite samples for laboratory analysis. Chemical analysis uses validated methods (e.g., ICP-MS, GC-MS, LC-MS/MS); speciation is essential for certain contaminants like arsenic and mercury. Dietary exposure is estimated by combining contamination levels with food consumption data using probabilistic models. Results can be stratified by age, gender, etc. Exposure is compared to health-based reference values (e.g., TDI, TWI) or assessed via the Margin of Exposure (MOE). Uncertainty is addressed using methods such as sensitivity analysis and Monte Carlo simulations. Results TDS provides a national overview of dietary exposure to chemical contaminants. Results typically include identification of major dietary sources of exposure (e.g., rice for arsenic, fish for mercury), demographic exposure profiles (e.g., higher intake in children due to body weight), and baseline exposure data for trend tracking and policy evaluation. Conclusions TDS are an essential tool in modern food safety. By integrating consumption and contaminant data in a realistic, whole-diet population-wide context, it supports risk assessment and evidence-based regulation. TDS are highly effective for chronic dietary exposure assessment, helping authorities prioritize risks and protect public health. Topic Relevance Amid growing concerns over food contamination, climate change, and evolving diets, TDS play a valuable role in supporting international food safety standards, informing national programs, and contributing to Sustainable Development Goals.
- Intestinal Permeability Studies using a more realistic barrier: performance of co-cultures of Caco-2/HT29-MTX cellsPublication . Figueira, Carolina; Gravato, Carlos; Alvito, PaulaThe intestinal barrier, essential for overall health, can have its permeability affected by certain food compounds and additives. Among various models, in vitro cellular monolayers are the most commonly used to study this process. Among these, Caco-2 cells—representing enterocytes—are commonly used, though they lack complexity to mimic some properties of the intestinal barrier. This limitation can be overwhelmed by co-culturing it with HT29-MTX cells, which allows the secretion of mucus and mimics goblet cell functioning. This study aimed to evaluate the intestinal permeability by assessing the paracellular and transcellular transport of lucifer yellow (LY) and propranolol (PR), two intestinal permeability markers, respectively, using a 9:1 co-culture of Caco-2/HT29-MTX cells. Cells were cultivated separately in complete medium. Functional monolayer formation was monitored over 28 days using transepithelial electrical resistance (TEER) measurements in triplicate plates, with values ranging from 450.6 to 1287.3 Ω·cm². Transport assays were conducted on day 21 by applying LY and PR to the apical compartment and measuring their passage to the basolateral side. Apparent permeability coefficients (Papp) and basal recovery values were estimated by fluorescence quantification. Statistical analyses were conducted to evaluate variability in TEER, Papp, and basal recovery results. The Shapiro-Wilk test was used to assess normality, and comparisons used one-way ANOVA followed by Tukey’s test or the Kruskal-Wallis test followed by Dunn’s test when requisites of ANOVA were not met. Significant differences in TEER values were observed between days 8–20 (p = 5.8e-11), 22–28 (p = 2.3e-09), and before vs. after transport on day 21 (p < 2.2e-16). For day 21 transport assays, a significant difference was found in LY basal recovery for two out of three plates (p = 0.03). As for the PR Papp values, there is a significant difference between duplicate plates (p = 0.005), as one plate was excluded due to a poor calibration curve fit. These findings will inform improvements to the protocol for assessing intestinal permeability using co-culture models. Thus, Caco-2/HT29-MTX co-culture appears to be a promising model for evaluating the impact of food components and additives on the intestinal barrier.
- Development of National recommendations for fish consumption in Portugal considering methylmercury exposurePublication . Fernandes, Paulo; Afonso, Cláudia; Bico, Paula; Bandarra, Narcisa; Borges, Marta; Carmona, Paulo; Carvalho, Catarina; Correia, Daniela; Gonçalves, Susana; Lopes, Carla; Lourenço, Helena; Monteiro, Sarogini; Nabais, Pedro; Oliveira, Luísa; Santiago, Susana; Severo, M.; Torres, Duarte; Dias, Maria da GraçaIntroduction: Fish is an important part of the Portuguese diet and a major source of long-chain omega-3 fatty acids. However, it also represents the main dietary source of methylmercury (MeHg), a neurotoxic compound especially harmful during critical stages of development such as pregnancy and early childhood. In response to European Commission Recommendation EU 2022/1342, Portugal undertook a national initiative to assess MeHg exposure and derive population-based consumption guidelines. Methodology: A multidisciplinary working group comprising six public institutions and coordinated by the Directorate-General for Food and Veterinary (DGAV) was established in 2018. The team performed a quantitative risk–benefit assessment (RBA) combining national data on MeHg, EPA, and DHA levels in commonly consumed fish species with food consumption data from the National Food and Physical Activity Survey (IAN-AF 2016). The assessment considered both the toxicological risks of MeHg and the nutritional benefits of omega-3 fatty acids. Results: The RBA showed that, for the general population, the benefits of fish consumption outweigh the risks of MeHg exposure. However, for vulnerable groups - pregnant and breastfeeding women and children under 10 years—the risks were more significant. As a result, differentiated dietary recommendations were developed. For the general population, a frequency of 4–7 servings per week of any fish species was advised. For vulnerable groups, 3–4 servings per week of fish species with medium to low MeHg levels were recommended, while species with high MeHg content (e.g., fresh tuna, swordfish, shark) should be avoided. Conclusions: The resulting recommendations were disseminated through a multilingual infographic, public presentation, and press release. Additional outreach actions targeting health professionals and school meal providers are planned to increase awareness among at-risk populations. Topic relevance: This work exemplifies a science-based approach to public health policy, combining food safety and nutrition to inform national dietary guidelines, with direct implications for risk communication and health promotion.
- Exposure to mycotoxins in the Portuguese adult populationPublication . Maris, Elias; Namorado, Sónia; Chen, A.; Pero-Gason, Roger; De Boevre, Marthe; De Saeger, Sarah; Silva, Maria João; Alvito, PaulaMycotoxins are toxic fungal metabolites commonly found in food, posing health risks such as immunosuppression, carcinogenicity, and endocrine disruption. Despite regulatory limits, chronic low-level exposure remains a concern. Understanding real-life exposure in populations is essential for effective risk assessment. This study aims to investigate mycotoxin exposure among young adults in Portugal, contributing to evidence-based public health interventions. This study leveraged data and biospecimens from the INSEF-ExpoQuim survey, a cross-sectional study nested within thPortuguese National Health Examination Survey (INSEF). Data was collected via REDCap-assisted telephone interviews, covering sociodemographic and exposure-relevant variables. A subset of 295 first morning urine samples was collected from adults aged 28–39 years between May 2019 and March 2020. Urine samples were analyzed by a newly optimized and validated LC-MS/MS method targeting 40 mycotoxins and/or their corresponding metabolites in urine. Urinary creatinine was measured using a validated colorimetric method to allow adjustment and standardization of mycotoxin concentrations, ensuring accurate exposure assessment and comparability. This methodological approach enabled a robust characterization of mycotoxin exposure in a representative Portuguese population cohort.The study included 58% females and 42% males. Most participants had medium to high education, and urbanization was nearly evenly split between towns/suburbs (36.9%) and rural areas (35.9%), with fewer living in cities (27.1%). The majority were employed, and sampling was primarily conducted in summer and autumn. The number of mycotoxin co-exposures in the Portuguese population ranged from 0 to 5, with two simultaneous exposures being most common (n = 160). Among the 40 mycotoxins analysed, deoxynivalenol and tenuazonic acid were most frequently detected, with frequency of detection of 85% and 96%, respectively. This study offers robust biomonitoring data on mycotoxin exposure in Portuguese young adults using a validated LC-MS/MS method. The high prevalence of deoxynivalenol and tenuazonic acid suggests low level dietary contamination. These findings support the need for continued monitoring and the integration ofhuman biomonitoring into national food safety strategies. Detailed sociodemographic analyses are planned to further clarify exposure patterns and enable targeted public health interventions.