Browsing by Author "Sampaio, Ana"
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- Aflatoxin Contamination of Various Staple Foods from Angola and MozambiquePublication . Matusse, Cláudio; Lucamba, Zelda; Bila, João; Macuamule, Custódia; Sampaio, Ana; Afonso, Sandra; Venâncio, Armando; Rodrigues, PaulaAflatoxins constitute a significant risk in staple foods produced in African countries. This research aimed to analyze the total aflatoxin (AFT) contamination of various staple foods in Angola and Mozambique. A total of 233 samples of corn, peanuts, beans, rice, and cassava flour collected from farmers or local markets from the province of Cuanza Sul, Angola, and the provinces of Gaza and Inhambane, South Mozambique, were analyzed for the presence of AFT using the lateral flow strip method via AgraStrip® ProWATEX® (Romer). The results showed that, from all matrices, the highest incidence and level of AFT were found in corn produced in Mozambique, with medians ranging from 6.5 to 66.5 μg/kg, with the samples showing values as high as 9200 μg/kg. Levels higher than the maximum admissible levels recommended by the Codex Alimentarius Commission for cereals and pulses (15 μg/kg) were observed in up to 90% of the corn samples, depending on the province. Corn produced in Angola showed lower amounts of AFT, with medians ranging from 1.2 to 7.7 μg/kg. Considering the maximum admissible levels for AFT recommended by the European Commission and the Codex Alimentarius Commission for cereals and pulses, the level of AFT contamination in staple food produced and consumed in the studied provinces is high and constitutes a public health risk for the population. Therefore, risk mitigation strategies are urgently needed.
- Agentes biológicos no combate das podridões da castanhaPublication . Agostini, Isadora; Silva, Sofia; Dallemole-Giaretta, Rosangela; Gomes-Laranjo, José; Sampaio, Ana; Rodrigues, PaulaApós a colheita da castanha (Castanea sativa Mill.), a maior preocupação das unidades de processamento é o controlo de agentes de deterioração, incluindo podridões. Atualmente, o fungo Gnomoniopsis smithogilvyi, agente causal da podridão castanha, tornou-se o principal causador de perdas de castanha em toda a Europa. Os objetivos deste trabalho foram: i) Analisar in vitro a atividade de um fungicida biológico comercial e de bactérias isoladas em laboratório no controlo dos agentes causais das podridões da castanha, em particular G. smithogilvyi; ii) Identificar a(s) bactéria(s) com potencial de controlo; iii) Estudar o modo de ação dos agentes selecionados contra G. smithogilvyi. Para tal, foram testados como potenciais agentes de controlo os produtos comerciais Serenade® ASO (Bacillus amyloliquefaciens) e Codasil® (solução de silício), e três isolados bacterianos. Como controlo positivo foi usado o fungicida Horizon® (Tebuconazol). Verificou-se que Serenade® ASO, Horizon® e a bactéria BCA1 tiveram efeito de controlo contra G. smithogilvyi, Trichoderma viridescens, Penicillium brevicompactum, Penicillium expansum, Mucor racemous e Ciboria batschiana. Codasil® estimulou o crescimento dos fungos. A bactéria BCA1 foi selecionada como potencial agente de biocontrolo, e foi identificada por métodos moleculares como B. amyloloquefaciens. Estudos sobre o modo de ação de Serenade® ASO e da bactéria BCA1 estão em curso.
- Aplicação de revestimentos na castanhaPublication . Ramalhosa, Elsa; Pereira, Ermelinda; Laranjo, José Gomes; Ferreira-Cardoso, Jorge; Gomes, A.; Vilela, Alice; Sampaio, Ana; Nunes, Fernando M.No presente capítulo pretende-se descrever as atividades realizadas no âmbito do Projeto ValorCast ao nível da aplicação de revestimentos hidrofílicos e hidrofóbicos com o intuito de reduzir a desidratação das castanhas após a colheita. Para a avaliação de revestimentos hidrofílicos foram realizados quatro estudos, nos quais se avaliou a aplicação dos seguintes compostos: (i) alginato, quitosano e proteína do soro, a 2% (m/v); (ii) quitosano (0,5, 1 e 2%, m/v) e farinha de mandioca (3 e 5%, m/v); (iii) revestimentos comerciais da empresa DOMCA, designadamente o FOOD-COAT®, PROALLIUM® e ambos em conjunto. Na aplicação de revestimentos de resíduos hidrofóbicos utilizou-se a parafina, parafina aditivada com timol e a cera de abelha. Através da realização do primeiro estudo verificou-se que os melhores resultados em termos da qualidade microbiológica do fruto foram obtidos com o quitosano. No segundo estudo observou-se que a aplicação de farinha de mandioca a 5% acarretou o aparecimento de bolores visíveis após 6 meses de armazenamento. Pelo contrário, a aplicação de quitosano a 1 e 2% e farinha de mandioca a 3% forneceram resultados promissores ao nível da redução do desenvolvimento microbiano, principalmente quando se consideram armazenamentos longos (> 3 meses). No terceiro estudo verificou-se que em relação à perda de peso, após o armazenamento durante 4 meses, o FOOD-COAT® foi o revestimento que mostrou o melhor desempenho, com a menor perda de peso (5 a 6%). No entanto, em relação aos microrganismos mesófilos aeróbios e bolores e leveduras, o PROALLIUM® foi o mais eficiente durante dois a três meses. Assim, a junção PROALLIUM®+ FOOD-COAT® pode ser vantajosa para se retardar a perda de peso e o desenvolvimento microbiano até três meses de armazenamento, perdendo a sua eficácia após esse período. Relativamente aos revestimentos hidrofóbicos à base de parafina e cera de abelha foram muito eficientes na prevenção da perda de água quando as castanhas foram armazenadas em condições forçadas. As castanhas revestidas com parafina ou com cera de abelha em termos sensoriais foram idênticas às castanhas antes do armazenamento, exceto com a adição do timol no tratamento da parafina pois conferiu aromas desagradáveis à castanha, provavelmente devido ao odor pungente do timol, mas em termos microbiológicos o timol teve uma ação essencial, pois permitiu diminuir a podridão das castanhas após o armazenamento.
- Chestnut brown rot and Gnomoniopsis smithogilvyi: characterization of the causal agent in PortugalPublication . Possamai, Guilherme; Dallemole-Giaretta, Rosangela; Gomes-Laranjo, José; Sampaio, Ana; Rodrigues, PaulaSweet chestnut (Castanea sativa Miller) is a nutritious food with high social and economic impacts in Portugal. The fungus Gnomoniopsis smithogilvyi (syn. Gnomoniopsis castaneae) is the causal agent of chestnut brown rot, and is currently considered one of the major threats to the chestnut production chain worldwide. Considering the lack of knowledge on both the disease and the causal agent in Portugal, studies were conducted in an attempt to develop the necessary control strategies towards the mitigation of the disease in a timely way. Isolates of G. smithogilvyi were selected from three varieties of chestnut from the northeast of Portugal, and were characterized at the morphological, ecophysiological and molecular levels. Tests of pathogenicity and virulence were also developed. Gnomoniopsis smithogilvyi was confirmed as the causal agent of brown rot disease in Portuguese chestnut varieties, which showed high susceptibility. The fungus showed high adaptability to chestnut substrates. The Portuguese isolates of G. smithogilvyi are morphologically and genetically similar to those from other countries, even though some physiological variability was observed among them.
- Chestnut brown rot and Gnomoniopsis smithogilvyi: characterization of the disease and of the causal agent in PortugalPublication . Possamai, Guilherme; Driss, Jihen Oueslati; Giaretta, Rosângela; Gomes-Laranjo, José; Camelo, Verónica; Sampaio, Ana; Rodrigues, PaulaSweet chestnut (Castanea sativa Mill.) is a nutritious food with high social and economic impact in Portugal. Fungal infection and rots lead to great economic and quality losses in stored chestnut. The fungus Gnomoniopsis smithogilvyi (syn. Gnomoniopsis castaneae) is currently considered one of the major threats to the chestnut chain worldwide. Considering the lack of knowledge on both the disease and the causal agent in Portugal, studies have been conducted in an attempt to timely develop the necessary control strategies towards the mitigation of the disease. Under this scope, the chestnut brown rot and its causal agent have been characterized for the first time in Portugal. The study was performed on chestnuts from Braganca, Portugal, that were received, processed and stored in a local industry during the growing season 2018-2019. Thirty-three samples were collected from different processing stages and from three chestnut varieties (Longal, Judia and Martaínha). Several isolates of G. smithogilvyi obtained were characterized at the morphological, ecophysiological, enzymatic and molecular levels. The fungus was also characterized in terms of pathogenicity and virulence. G. smithogilvyi was confirmed as the causal agent of brown rot disease in Portuguese chestnut varieties, which showed high susceptibility. The fungus showed high adaptability to chestnut substrates. The Portuguese isolates of G. smithogilvyi are morphologically and genetically similar to those isolated in other countries, even though some physiological and enzymatic variability was observed among the Portuguese isolates. Post-harvest control strategies towards the mitigation of the disease are discussed.
- Contamination by aflatoxins in different food matrices produced and consumed in MozambiquePublication . Matusse, Cláudio; Macuamule, Custódia; Bila, João; Sampaio, Ana; Venâncio, Armando; Rodrigues, PaulaMycotoxins are toxic metabolites produced by various moulds that frequently contaminate food worldwide, being significant contributors to food losses in developing countries. In Mozambique, there is no comprehensive knowledge of the risk of mycotoxins in the country, nor structured actions to reduce the impacts of mycotoxins and promote health and food security in disadvantaged populations. This research aimed to analyse the level of contamination by aflatoxins in different food matrices produced and consumed in southern Mozambique. Ten samples were collected from each matrix (maize, rice, and peanut) in each of the 3 districts (Chongoene, Manjacaze and Chókwe) of Gaza province, and 10 peanut samples in each of the 3 districts (Massinga, Inhambane and Inharrime) of Inhambane province, in a total of 120 samples. Samples were collected between January and June 2023 from local markets and producers. Samples were analysed for total aflatoxins using the lateral flow strip, AgraStrip® Pro WATEX® (Romer Labs) method. Results showed that, from all matrices, the highest levels of aflatoxins were found in maize, with averages ranging from 369.2 (in Manjacaze) to 1,972.6 ug/kg (in Chokwe). Average aflatoxin levels in rice ranged between 1.2 (Chongoene) and 63.08 ug/kg (Manjacaze). Peanuts from the province of Inhambane were more contaminated than those from Gaza, with averages ranging from 5.6 (Manjacaze, Gaza) to 95 ug/kg (Inhambane). Considering that the maximum admissible levels for total aflatoxins recommended by the Codex Alimentarius Commission for cereals and pulses is 15 ug/kg, the level of aflatoxin contamination in food produced and consumed in southern Mozambique is high and constitutes a public health risk for the population. Therefore, risk mitigation strategies are urgently needed.
- Controlo das podridões da castanhaPublication . Rodrigues, Paula; Gomes, A.; Gomes-Laranjo, José; Sampaio, AnaA maioria da castanha portuguesa tem como destino o mercado nacional e internacional do fresco. Em termos médios, a castanha chega aos operadores com cerca de 15 a 30% de castanha bichada, dependendo das condições climáticas do ano e do maneio do souto. Esta perda pode representar cerca de 10 000 t de castanha (cerca de imediato para refugo. Esta elevada percentagem, além de causar prejuízos significativos, levanta sérios problemas no processamento da castanha visando a sua colocação no mercado. A recente proibição da utilização na Europa do brometo de metilo para a desinfestação da castanha, veio criar novas dificuldades aos operadores, que ainda não estão completamente solucionadas. O método atualmente mais usado é a imersão de castanha em água quente (choque térmico). Este processo tem criado dificuldades de conservação da castanha nos processos de exportação de longo curso. Outras soluções foram já tentadas com algum sucesso quanto ao efetivo controlo da praga, como a irradiação e a pressurização. Contudo apresentam limitações à sua execução quanto aos custos envolvidos e à capacidade de processamento de grandes quantidades de castanha. Assim, outras possibilidades deverão ser consideradas. As unidades de processamento debatem-se ainda com o aparecimento muito frequente de podridões nas castanhas, provocadas por diversos fungos (Penicilllium sp., agentes causadores da podridão verde; Ciboria batschiana (syn. Sclerotinia pseudotuberosa), agente causador da podridão negra; Gnomoniopsis sp. e Phoma endogena, agentes causadores da podridão castanha, ou mumificação) que podem levar à destruição completa do lote de castanha. Este problema é um óbice ao prolongamento no tempo da oferta de castanha de qualidade, conforme as necessidades do mercado exigem atualmente.
- Ensaio de campo para controlo de Gnomoniopsis smithogilvyiPublication . Gomes, Ana; Sampaio, Ana; Rodrigues, Paula; Gomes-Laranjo, JoséGnomoniopsis smithogilvyi L.A. Shuttleworth, E.C.Y. Liew & D.I. Guest, é o principal agente da podridão castanha em castanhas pós-colheita, uma ameaça à sustentabilidade do mercado na Europa. Com objetivo de reduzir os níveis de infeção da castanha foi avaliado, em campo, o impacto da aplicação de produtos comerciais no controlo G smithogilvyi. Árvores da variedade ‘Bouche de Bétizac’ com 8 anos (a), foram tratadas 3X com 3 produtos, Bacillus amyloliquefaciens e tebuconazol (2 em junho e 1 em julho), e uma solução nutritiva de óxido de silício (em junho, julho e agosto). Num segundo souto, árvores da variedade ‘Judia’ com 20 anos (b) foram tratadas com uma mistura (mix) de tebuconazol, cobre e tiaclopride, numa única aplicação, no início de setembro. Ambos por pulverização foliar. Foram colhidos 120 (a) e 30 (b) ouriços por tratamento, para avaliação biométrica, 200 (a) e 43 (b) castanhas por tratamento para avaliação externa e interna e 10 castanhas por tratamento para a análise microbiológica. Em a) a solução nutritiva promoveu a formação de castanhas com melhores parâmetros biométricos. Em b) as castanhas tratadas apresentarem melhores resultados relativamente às do controlo. Nas análises microbiológicas e para todos os tratamentos, foi detetado G smithogilvyi, exceto nas castanhas tratadas com tebuconazol, a solo ou em mix. Análises efetuadas na farinha de castanha proveniente dos tratamentos com tebuconazol, armazenadas a -20 ºC, não detetaram resíduos desta substância.
- Enzymes and secondary metabolites profiles of Gnomoniopsis smithogilvyi are affected by chestnut mediumPublication . Sampaio, Ana; Camelo, Verónica; Fraga, Irene; Gomes, A.; Sulyok, Michael; Gomes-Laranjo, José; Dias, Albino A.; Rodrigues, PaulaChestnut tree (Castanea sativa Mill) is a crop with high economic and social importance in Trás-os-Montes Region. The pre and post-harvest quality of its nuts can be affected by many factors, being the lasses dueto fungi very large. During the last decade a new endophyte fungus, Gnomoniopsis smithogilvyi, causing brown rot, has been isolated from both rotten and healthy fruits, and its growth seems to be related with the increase of air temperatura and rainfall during spring. The present study aims to understand the influence of chestnut substrate on G. smithogilvyi biochemistry, in arder to develop strategies to reduce its incidence in the fruit and improve the contrai of brown rot. lnitially, the presence of the enzymes involved in the decomposition of chestnuts, such as amylase, proteases, carboxymethylcellulase (CMCase), ~-glucosidase, xylanase, among others, was investigated. Further, some hydrolase activities were evaluated in two isolates of G. smithogilvyi incubated in potato (PDB) and chestnut media (CM) along an incubation period (3, 7 and 14 days), in arder to study the effects "isolate", "medium" and "incubation period" on enzymes production. Also, the synthesis of secondary metabolites in fungai dry biomass was assessed by Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Ali isolates produced the enzymes screened and, in general, the enzyme production varied between the isolates (P< 0.0000), the media (P< 0.0000) and along the incubation period (P< 0.0000). Amylase activity was positively correlated with xylanase (P< 0.0001), CMCase (P< 0.0001), and Avicelase {P< 0.01), xylanase with CMCase (P< 0.01) and ~-glucosidase with Avicelase (P< 0.0001 ). By contrast, ~-glucosidase was negatively correlated with CMCase {P< 0.01 ). Twenty secondary metabolites were detected along the incubation: eight in both isolates and media, tive and three only in isolates grew in PD o r CM, respectively. Some of these metabolites had been associated with other fungi and have known biological activities.
- Evaluation of corn drying and storage techniques to mitigate damage and total aflatoxin contamination in MozambiquePublication . Matusse, Cláudio ; Bila, João; Macuamule, Custódia; Sampaio, Ana; Venâncio, Armando; Rodrigues, PaulaContamination of corn by molds and aflatoxins is a major problem in Mozambique, and appropriate drying and storage of this essential food crop is crucial. This study aimed to evaluate the effects of different drying and storage techniques traditionally employed by smallholder farmers in the province of Gaza, Mozambique, in preventing degradation and aflatoxin contamination of corn. Two trials, one for drying and one for storage, were carried out in 2024 and 2025, based on the information resulting from interviews applied to 90 farmers. For corncob drying, three methods were tested: ground, straw mat and tarpaulin. For grain storage, hermetic (metallic drums and PICS bags) and non-hermetic (raffia bags and traditional barns) methods were tested for 12 months of storage. Grain moisture, damage and total aflatoxins were evaluated. All drying methods resulted in a sharp corn moisture reduction, but tarpaulin drying showed the lowest grain damage. No significant differences were observed in aflatoxin content between drying methods. For storage, corn grains (initial 12 % moisture content) stored in metallic drums and hermetic bags were intact after 12 months, while storage in traditional barns and raffia bags resulted in highly (60-80 %) and completely (100 %) damaged grain after 3 and 6 months, respectively. Corn stored in raffia bags showed the highest aflatoxin contamination levels. This study confirmed tarpaulin and hermetic technologies as the most effective methods of corn drying and storage. However, information, demonstration and training are still required for farmers to implement these technologies, which are more expensive than the less effective ones.