DAN - Posters/abstracts em congressos internacionais
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- Determination of trace elements in agglomerated cork stoppers using inductively Coupled Plasma Mass Spectrometry (ICP-MS)Publication . Gueifão, Sandra; Nascimento, Ana Cláudia; André, Catarina; Coelho, Inês; Castanheira, IsabelQuercus Suber L. is a native species of the Mediterranean region yielding a thick bark, known as cork, used mainly in the production of wine stoppers. The levels of trace elements are an important component of quality, safety and origin of the agglomerated corks stoppers in contact with food. In the present work the concentration of the following elements was determined: Chromium (Cr), Nickel (Ni), Arsenic (As), Cadmium (Cd), Selenium (Se), Lead (Pb), Iron (Fe), Zinc (Zn), Copper (Cu) and Manganese (Mn). Since almost no published work can be found on this subject it was necessary to study all stages of the process. Sampling was made by the producer who sent representative bagged samples to the laboratory. Subsequently it was necessary to have a reliable sample preparation method before the analysis. To do so the sample preparation step was optimized by employing and comparing two distinct methods to destroy the organic matrix: dry ashing and microwave digestion. Afterwards samples were analysed by two different techniques, trace elements were determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and the remaining ones by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). Both techniques enable the quantification of elements with ICP-MS allowing lower detection limits (ppb and/or ppt) than ICP-OES (ppm) in a complex matrix such as agglomerated cork stoppers. Several elements were found in the sample. These elements may originate from the cork or by contamination of the manufacturing process of agglomerated cork stoppers. Microwave digestion proved to be the best sample preparation method since the results from reproducibility and repeatability were better than the ones obtained from dry ashing.
- Method optimization for the determination of total arsenic and selenium content in fish by ICP-MS preceding to speciation studies.Publication . Inês, Coelho; Ribeiro, Sandra; Castanheira, IsabelThe present work constitutes the first task of a three year project that aims for the optimization and validation of a methodology to determine the total concentration of Arsenic (As) and Selenium (Se) and its species in fish products by using HPLC-ICP-MS. Prior to initializing speciation studies the method for determination of total arsenic and selenium content was optimized. For that purpose reference materials (DORM-3 and BCR-627) were used as well as spiked samples. Sample preparation using closed vessel microwave digestion was optimized by trying several nitric acid/peroxide hydrogen ratios and varying time and temperature conditions. Results were evaluated by calculating the extraction yield of trace elements from matrix and trueness of reference materials results. Parameters such as repeatability, reproducibility and linearity were evaluated using real samples such as tuna fish and sole. ICP-MS conditions were optimized on a daily basis and calibration solutions were prepared fresh every day. Recovery percentages indicated that digestion conditions are complex and food matrix dependent. The use of the correct internal standards, in this case Yttrium and Rhodium were chosen, as well as its concentration is essential for obtaining accurate results. Also fundamental is matching as much as possible the concentration of nitric acid used in the preparation of calibration solutions to the one from test solutions after microwave digestion. Recovery using commercial calibrants and reference materials was the best parameter to assess the adequacy of the analytical procedure. The obtained results were supported by good laboratory performance in collaborative studies. In future work methods for identifying and quantifying arsenic and selenium species by using HPLC-ICP-MS will be developed.
- Determination of Total Selenium and Selenomethionine in cow milk by HPLC coupled to ICP-MSPublication . Gueifão, Sandra; Coelho, Inês; Castanheira, Isabel; Jitaru, Petru; Fisicaro, PaolaThis study focused on the determination of total selenium and selenomethionine (SeMet) species in milk samples. Accurate determination of total selenium was carried out by Inductively Coupled Plasma Mass Spectrometry and Isotope Dilution (ID-ICP-MS). SeMet species was determined by a hyphenated technique, namely High Performance Liquid Chromatography coupled with ICP-MS equipped with a dynamic reaction cell (HPLC-DRC ICP-MS). In order to eliminate possible interferences (Ar-Ar, Ca-Ca and Ca-Ar) that occur either for determination of total selenium and SeMet, the DRC-ICP-MS operating conditions were optimized, using different flows of gases (Helium/Hydrogen) mixtures. The milk sample was digested by using a closed-vessel microwave system and various parameters, such as the ratio nitric acid/peroxide hydrogen, temperature, pressure and time were investigated. The ID was also compared with the standard addition method. Reproducibility, repeatability and trueness of the method for the determination of total selenium were evaluated using two reference materials, SRM-1549 and BCR-063R. The results obtained were in both cases in a good agreement with certified values. Both enzymatic and acid hydrolysis of the milk proteins were investigated as extraction procedures in view of SeMet determination in milk and the conditions used in this work seemed effective to achieve accurate determination of total selenium and SeMet in this difficult matrix.
- Parental socioeconomic and educational level and chil overweight - lessons from a municipality based studyPublication . Silva, Ana Lúcia; Lopes, Sara; Breda, João; Rito, AnaINTRODUCTION: The prevalence of childhood obesity is rising rapidly in Portugal, reaching one of the worst positions in the European Union. Inadequate food habits with high intake of high energy dense foods, seems to be one of the main factor behind this epidemic. Family socioeconomic status also appears to be an obesogenic factor, particularly parents’ educational level and their income. To better understand the association of unbalanced dietary habits and socioeconomic environment on children nutritional status and to develop effective prevention strategies, are the main aims of this municipality study METHODS: A cross-sectional study was conducted on five municipalities (Viana do Castelo, Fundão, Oeiras, Seixal and Montijo), which included 3275 children (6-9 years old), attending the universe of public elementary schools. Childhood nutritional status was assessed by anthropometric parameters (weight and height) considering the CDC growthcharts criteria percentiles of BMI. Children’s food habits, socioeconomic condition and parent’s level education were collected by a family questionnaire. RESULTS: Prevalence of childhood overweight (BMI≥P85) was 32,1%, and over 14% of children were obese (BMI≥P95). Pre-obesity (P85≤ BMI< P95) prevalence was higher among girls (18,1%) than boys (17,8%). The consumption of fast food group and candies occurred mainly in every 15 days (48,4% and 35,5% respectively), pastry products showed a higher frequency of 1-3 times a week (41,5%). The percentage of children consuming vegetables, at least daily, varied with nutritional status: 23,0%; 25,7%; 26,2%; 21,0% in underweight, normal, pre-obese and obese children. Overweight was associated with parent´s low socioeconomic status, and middle parents educational level. CONCLUSION: Further careful analysis will help to better understand the role of obesogenic factors. This knowledge may identify additional potential effective interventions at local level in order to reverse the obesity trends in Portuguese children.
- Arsenic content in fish and associated measurement uncertainty as a metrological parameter for Total Diet StudiesPublication . Coelho, Inês; Gueifão, Sandra; Matos, Ana Sofia; Santos, Rui; Castanheira, IsabelTotal Diet Studies (TDS) are the most important tools to assure that chemical contaminants presence in foodstuffs remains within safety levels. Reliability of data provided by laboratories to assess the effectiveness of measurements aiming at reducing the risk of exposure to chemical hazards is of paramount importance. Evaluation of measurement uncertainty associated with a result is an important parameter in assessing the sources of analytical data variability. Two methods to estimate uncertainty in analytical measurement of arsenic in fish are discussed. Measurement uncertainty was estimated for the determination of arsenic content in fish samples by Inductively Coupled Mass Spectrometry (ICP-MS). The work addressed both approaches accepted by Eurolab and NIST: modeling (bottom up) and empirical (top down). The Ishikawa diagram was used to identify the most significant sources of uncertainty. The mathematical modeling techniques to assess uncertainty components based on a classical model that accounts for all recognized significant sources of errors was similar to the top down based on validation data from interlaboratory comparison studies. Both methods showed that analytical variability in arsenic content was less than 10%.
- A proposal to guarantee metrological traceability in determination of heavy metals contents in cork stoppers by ICP-MSPublication . Gueifão, Sandra; André, Catarina; Coelho, Inês; Castanheira, IsabelThe compliance of heavy metals contents in cork with European Legislation for materials in contact with food and beverages are an important requirement of safety and quality of cork stoppers. However there are few specific regulations for cork. Therefore metrological strategies to assure reliability of analytical measurement results are crucial to ensure that the quantification of chemical contaminants are effectively in line with limits established in law. In this work a general approach is described for implementation of metrological traceability covering all analytical procedure for determination of Arsenic, Lead, Nickel, Chromium and Cadmium contents in cork stoppers with the potential to migrate to beverages. A flowchart diagram to identify the critical points of experimental procedure that need to be under metrological conditions is described. The experimental procedure encompasses the test conditions to simulate migrations for beverages, digestion procedure and determination by ICP-MS. The most important metrological control points to assure that measurements will be traceable to SI were: validation of analytical method to assure correct identification and quantification of metal under study; measurement of recovery of the spikes to estimate analyte lost during the digestion of samples; use of appropriate calibrants to calibrate the ICP-MS; regular participations in PT schemes for contaminants under study; estimation of associated measurement uncertainties. This metrological approach seems realistic to guarantee the traceability of assigned values of inorganic contaminants in cork stoppers and to demonstrate concordance of test conditions with ISO/IEC 17025 requirements.
- Relationship between family socioeconomic and educational level and childhood overweight from a Portuguese municipality based studyPublication . Ramos, Carlos; Silva, Ana Lúcia; Carvalho, Maria Ana; Rito, AnaINTRODUCTION: The prevalence of childhood obesity is rising rapidly in Portugal, reaching one of the worst positions in the European Union. Inadequate food habits with high intake of high energy dense foods, seems to be one of the main factor behind this epidemic. Family socioeconomic status also appears to be an obesogenic factor, particularly parents’ educational level and their income. To better understand the association of unbalanced dietary habits and socioeconomic environment on children nutritional status and to develop effective prevention strategies, are the main aims of this study. METHODS: A cross-sectional study (MUNSI) was conducted on five, which included 3173 children (6-9 years old), attending the universe of public elementary schools. Childhood nutritional status was assessed by anthropometric parameters considering the CDC growthcharts criteria percentiles of BMI. Children’s food habits, socioeconomic condition and parent’s level education were collected by a family questionnaire. RESULTS: Prevalence of overweight (BMI≥P85) was 32.1%, and 14.3% for obesity (BMI≥P95). The risk of obesity was higher in medium income families (851-1500€: OR=4.0 (1.1-14.1)), compared with families’ incomes over 3750€/month. We also found that parents’ educational level was correlated with the risk of obesity in children. Lower mother´s educational level showed higher prevalence (20,8%) and risk of childhood obesity: OR=2.8 (1.8-4.5) and again for lower fathers educational level with higher childhood obesity (16.7%) and OR=2.1 (1.2-3.4) CONCLUSION: Data showed that obesity is not independent from parents’ socioeconomic status and parents’ educational level, where this condition seem to be related with the likelihood to develop childhood obesity.
- Activity of chitosan films against different microorganismsPublication . Sanches-Silva, A.; Maia, C.; Furtado, R.; Ribeiro, T.; Paseiro, P.; Sendón, R.; Rodríguez-Bernaldo de Quirós, A.; López-Cervantes, J.; Sánchez-Machado, D.I.; Bueno, C.; Soto Valdez, H.; Angulo, I.; Aurrekoetxea, G.P.; Bilbao, A.; Costa, H.S.Chitosan is a hydrophilic polysaccharide which derives from chitin by deacetylation. It has several applications, namely as a film that can be applied to preserve the quality and increase the shelf-life of food. Chitosan is insoluble in most solvents but it is soluble in dilute organic acids such as formic acid and acetic acid[1]. The properties of chitosan depend on the degree of deacetylation (DA) and molecular weight (MW). A broad antimicrobial activity has been attributed to chitosan, either for gram-negative, gram-positive bacteria and fungi. The aim of the present study is to evaluate the antimicrobial activity of a chitosan film prepared by casting. The chitosan was obtained from shrimp waste collected from shrimp processing factories of South Sonora (Mexico). Four bacteria (Bacillus cereus; Escherichia coli; Staphylococcus aureus and Listeria monocytogenes) and one fungus (Botrytis cinerea) were evaluated. Although L. monocytogenes and B. cinerea growth was not inhibited by the chitosan film, results showed a clear growth-inhibitory effect, at the two bacteria concentration levels tested, for B. Cereus, E. coli and S. aureus. Different antibacterial mechanisms have been proposed to explain chitosan antimicrobial activity[2-3]: i) chitosan may form an external barrier which inhibits essential nutrients adsorption; ii) chitosan can also penetrate the microbial cell, disturbing the metabolism of the cell by inhibiting the mRNA and protein synthesis; iii) chitosan may have an ionic surface interaction with the bacteria originating wall cell leakage. Although these mechanisms may take place simultaneously, the antimicrobial activity may also depend on the properties of chitosan (DA and MW).
- The development and validation of a novel computer program to assess food and nutrition intake in Portuguese schoolchildrenPublication . Carvalho, Maria Ana; Pereira Miguel, José; Rito, Ana IsabelIntroduction: Food and nutrition are important determinants of non-communicable diseases such as childhood obesity which is a public health priority. Understanding how to prevent it remains a research question. However the design of potentially effective interventions is hampered by the general lack of good-quality data available. There is no validated methodology available to assess food and nutrition intake in school age Portuguese children. The purpose of this study is to develop and validate, for the first time in Portugal, a novel engaging method of assessing food and nutrition intake of school age Portuguese children. Methods: A self-administered computerized 24-Hour Recall questionnaire will be designed to 7-10 years-old Portuguese children. The research will have the following chronological developmental phases: 1) Questionnaire food items selection and psychometric tests (reliability and validity tests) and 2) Pilot study (two days of dietary intake will be evaluated because one administration of the 24-Hour Recall is of little use in estimating children’s usual energy and nutritional intake). Results (expected): Developmental of a novel, valid and engaging method of assessing food and nutrition intake, set within a user-friendly interface and the collection of valid information about food and nutritional intake of school age Portuguese children. Conclusion: The design and implementation of this study will be an essential prerequisite for monitoring the nutritional status of school age Portuguese children as well as will lead to perform several epidemiological researches on the links between diet and health, which help develop sound public health policy, direct and design health programs.
- Relação entre as dimensões socioeconómicas, demográficas e ambientais com a obesidade infantil em Portugal no âmbito do projecto Comunitário - MUNSIPublication . Silva, Ana Lúcia; Ramos, Carlos; Carvalho, Maria Ana; Breda, João; Rito, AnaINTRODUÇÃO: O excesso de peso e a obesidade têm vindo a aumentar consistentemente na União Europeia (EU) e particularmente em Portugal, afectando cada vez mais crianças e adolescentes. O programa de acção comunitário no campo da saúde identifica como áreas prioritárias de actuação a protecção dos cidadãos contra as ameaças à saúde e a promoção de políticas que conduzam a estilos de vida mais saudáveis. Neste sentido é particularmente determinante o papel das autarquias locais, pela sua intervenção ao nível da promoção da actividade física, da existência de um ambiente urbano adequado e na disponibilização dos cidadãos particularmente na comunidade escolar de alimentos saudáveis. O Projecto MUNSI (2008 a 2011) desenvolve-se nos municípios do Fundão, de Oeiras, do Montijo, do Seixal e de Viana do Castelo e tem como objectivo a concepção e operacionalização de um Sistema Integrado de Vigilância Nutricional de suporte a políticas locais. MÉTODOS: O estado nutricional da população infantil inscrita no 2º ano do 1º ciclo do ensino básico da comunidade escolar dos Municípios envolvidos (n=167), no ano 2008/2009, foi avaliado segundo o critério do CDC (2000) e relacionado com as dimensões socioeconómicas, demográficas e ambientais recolhidas através de um questionário aplicado às famílias das crianças em estudo. RESULTADOS: 3173 crianças foram avaliadas, 50,6% eram do sexo feminino, com uma média de idades de 7,5 anos (±0,8). A prevalência de excesso de peso foi de 32,1% (IMC≥P85), das quais 14,3% eram obesas (BMI≥P95). Verificou-se que crianças sem irmãos e cujas famílias apresentavam baixos níveis socioeconómicos (<1500€/mês) apresentavam um factor associado de risco ao desenvolvimento da obesidade (OR=1,6; 95%CI: 1,1-2,3) e (OR=3,9; 95%CI: 1,4-10,8). Comportamentos sedentários como o visionamento televisivo (>2horas) mostraram associações semelhantes (OR=1,3; 95%CI: 1,0-1,7) e igualmente em crianças com uma duração de sono ≤8horas (OR=1,5; 95%CI: 1,1-2,1). Crianças que não foram amamentadas e macrossómicas também mostraram maior risco associado à obesidade (OR=1,6; 95%CI: 1,1-2,2) e (OR=2,5; 95%CI: 1,3-4,6). Observou-se ainda que a maior parte das crianças tomava o pequeno-almoço diariamente (96,9%) e almoçava na escola (84,1%). O consumo diário de doces demonstrou uma maior tendência no desenvolvimento da obesidade (OR=2,3; 95%CI: 1,2-4,3) contrariamente ao verificado naquelas que consumiam sopa diariamente (OR=0,6; 95%CI: 0,3-1,0). CONCLUSÕES: Conclui-se que programas de acção comunitária identificam dimensões prioritárias de actuação na prevenção da obesidade, designadamente de carácter socioeconómico, demográfico e ambiental na promoção de políticas que conduzam a estilos de vida mais saudáveis.