Percorrer por autor "Santos, Cristina G."
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- Authentication of a traditional game meat sausage (Alheira) by species-specific PCR assays to detect hare, rabbit, red deer, pork and cow meatsPublication . Amaral, Joana S.; Santos, Cristina G.; Melo, Vítor S.; Oliveira, Beatriz; Mafra, IsabelAlheira is a traditional meat product that is typical from the Northeast region of Portugal and much appreciated. It is a sort of sausage produced industrially or by small artisanal producers, having wheat bread and meats as main ingredients. Game meat Alheira (Alheira de caça) is considered one of the most attractive products since it should include different game meats. The aim of the present work was to identify the species of origin of meats added to game meat Alheira samples to verify their compliance with labelling. Species-specific PCR assays targeting mitochondrial genes of rabbit, hare, red deer, cow and pork were optimised and applied to industrial and artisanal samples. The assays revealed adequate specificity for each of the targeted species, with sensitivities of 0.01-0.1%. Results of the evaluation of 18 commercial samples identified several inconsistencies with labelling, namely the absence of declared game species (red deer, hare and rabbit) in ten samples and the presence of undeclared cow species in nine of the analysed samples. These findings indicate the occurrence of misleading labelling, suggesting the adulteration by substitution of game meats by cow meat to reduce production costs and the need to protect and valorise this kind of traditional food product.
- Comparação de métodos de extração de DNA para a detecção de resíduos de avelã em chocolate como potencial alergéneoPublication . Melo, Vítor S.; Santos, Cristina G.; Costa, Joana; Mafra, Isabel; Amaral, Joana S.; Estevinho, Leticia M.; Oliveira, BeatrizAs reacções alérgicas causadas pela ingestão de alimentos constituem um problema emergente na gestão da segurança alimentar. De modo a salvaguardar a saúde dos consumidores, os ingredientes que possam causar reacções alérgicas devem ser devidamente rotulados e a contaminação cruzada deve ser evitada. Entre as diversas reacções provocadas pelos alimentos que contêm produtos de casca rija (chocolate, bolachas e bolos), as provocadas pelos alimentos que contêm avelã são consideradas das mais perigosas devido à sua frequência e gravidade [!]. Recentemente, a detecção de resíduos de alergénios recorrendo a técnicas baseadas no DNA, em particular, na reacção em cadeia da polimerase (PCR) têm-se mostrado alternativas promissoras aos métodos imunológicos correntes. Contudo, matrizes complexas corno o chocolate, contêm polissacarídeos e polifenóis que inibem a PCR. Actualmente existem diversos kits comerciais que permitem a extracção de DNA, mas apenas um número Limitado permite a obtenção de DNA em quantidade e pureza adequadas para PCR. Pretendeu-se com este trabalho comparar diversos métodos de extracção de DNA (CTAB, Wizard, Nucleospin e Wizard Magnetic) com e sem a adição de polivinilpirrolidona (PVP) e/ou RNAse. Para tal, prepararam-se misturas de referência contendo quantidades conhecidas de avelã em chocolate (0.01-10%) e procedeu-se à extracção. O rendimento e pureza dos extractos foram avaliados por espectrofotornetria. Para a detecção de avelã foram usados primers específicos para o gene hspl para a obtenção de fragmentos de 100 bp [2]. Os resultados mostraram que os métodos Wizard com RNAse e CTAB, ambos com a adição de PVP 1%, permitiram níveis de amplificação semelhantes até extractos com 0,05% de avelã, com rendimentos mais elevados com o método Wizard (-100 ng/μL). Os métodos Nucleospin Food kit com RNAse e Wizard Magnetic apresentaram rendimentos semelhantes ao método Wizard, tendo também permitido a detecção de 0,05% de avelã, no entanto evidenciaram pouca reprodutibilidade na amplificação.
- Comparision of DNA extraction methods to detect trace amounts of tree nut allergens in chocolatesPublication . Costa, Joana; Melo, Vítor S.; Santos, Cristina G.; Mafra, Isabel; Amaral, Joana S.; Estevinho, Leticia M.; Oliveira, BeatrizFood-induced allergies represent an emerging problem of food safety. Thus, to safeguard the health of sensitised consumers, food ingredients that may cause allergic reactions should be properly labelled and possible cross-contamination should be avoided. Among food allergies, abnormal immunological responses towards tree nuts are pointed as a frequent source of serious atypical reactions, in which the hypersensitivities associated to almond and hazelnut ingestion are considered dangerous due to their incidence and severity [1 ,2]. Although immunological methods have been used for the direct detection of the almond and hazelnut allergens with high sensitivity, these assays are susceptible to cross-reactivity with other tree nuts
- Detecção de adulterações em alheiras de caça : identificação de carne de aves com base em marcadores molecularesPublication . Santos, Cristina G.; Melo, Vítor S.; Mafra, Isabel; Amaral, Joana S.; Estevinho, Leticia M.; Oliveira, BeatrizA avaliação da autenticidade de produtos córneos inclui diferentes aspectos, como a substituição de carnes com valor económico elevado, por outras de menor valor, e a presença de espécies não declaradas no rótulo [I]. Actualmente, para além da Alheira tradicional, produzida à base de carne de porco e/ou de aves (galinha e peru) são comercializadas Alheiras de caça, geralmente com preço mais elevado. Neste tipo de produtos processados, torna-se difícil a diferenciação das carnes utilizadas, pelo que são propícios a adulterações. Várias técnicas analíticas com base na detecção de proteínas (cromatográficas, electroforéticas e imunológicas) têm sido aplicadas na identificação de espécies em produtos cárneos.
- Detection of adulterations in tradictional portuguese game meat products by polymerase chain reaction techniquePublication . Santos, Cristina G.; Melo, Vítor S.; Amaral, Joana S.; Oliveira, Beatriz; Mafra, IsabelAuthenticity assessment and fraud detection in processed meat products have becn attracting an increased attention driven by public health, economic and legal cancems, and also for religiolls reasons. Currcntly, ooe af the major issues conceming adulterations in the meat indust:ry regards the fraudulent substitution af higher commercial valued meat species by less expensive oDes [1]. The manufacture af traditional meat products is a long-established practice in the Northeast of Portugal. One of the most appreciated products is called "Alheiras", which are traditional smoked fermented sausages, mainly produced with pork and poultry meat. In addition to the two Portuguese Alheiras with Protected Geographical Indication (pGI), other types of "Alheiras" are now available in the market, including the ones produced with game meat. Due to the game meat particular taste, intense Oavour and seasonality, it generally eommands higher prices compared to other meats [1]. Sinee game meat "Alheiras" should, totally or partially, include different types of game meat, they are particularly prone to fraudulent meat substitutions.
- Detection of partridge meat for the authentication of “alheiras de caça” using polymerase chain reactionPublication . Santos, Cristina G.; Melo, Vítor S.; Mafra, Isabel; Amaral, Joana S.; Costa, Joana; Oliveira, BeatrizThe manufacture or traditional meat products is a long-eslablished lradition in Northeastern region of Portugal, in particular the case of "Alheiras" Besides the traditional "Alheiras" mainly produced with pork and poultry meat, others are currently available in lhe market. which are produced with diffcrcnt game meats, such as "Alhciras de caça" Since this kind of mcat products are prepared using more expensive meats, they are prone to adulterations due to the economic profit that might result from the replacement or decrease of those high valued meats
- Identification of duck, partridge, pheasant, quail, chicken and turkey meats by species-specific PCR assays to assess the authenticity of traditional game meat Alheira sausagesPublication . Amaral, Joana S.; Santos, Cristina G.; Melo, Vítor S.; Costa, Joana; Oliveira, Beatriz; Mafra, IsabelGame meat Alheira (Alheira de caça) sausage is a traditional fermented product typical from the Northeast region of Portugal, having bread and meats (including game) as main ingredients. It is a particularly appreciated product by consumers that commands higher prices, especially in comparison with the common Alheira produced with pork and poultry meats. Following our previous work in which several mammalian game meat species were successfully identified in game meat Alheira sausages for authentication purposes, the present work aimed at identifying game bird's species for the overall assessment of labelling compliance. For that purpose, several species-specific PCR assays targeting mitochondrial DNA for the detection of game and domestic bird's meat, namely duck, partridge, pheasant, quail, chicken and turkey were developed, optimised and applied to commercial samples of game meat Alheira for their authentication. The assays revealed a high specificity and sensitivity to detect the addition of all evaluated species down to a level of 0.01% (w/w). PCR results indicated the existence of several inconsistencies with the labelled information, namely the absence of declared game species (duck, partridge and pheasant) and the presence of undeclared poultry meat, pointing out to adulterations owing to substitution of game by domestic meat species. Since this is considered a high-valued traditional product that should be valorised and protected, this work puts in evidence the need for inspection programs to enforce regulation. © 2014 Elsevier Ltd.
- Identification of hare meat by a species-specific marker of mitochondrial originPublication . Santos, Cristina G.; Melo, Vítor S.; Amaral, Joana S.; Estevinho, Leticia M.; Oliveira, Beatriz; Mafra, IsabelMeat species identification in food has gained increasing interest in recent years due to public health, economic and legal concerns. Following the consumer trend towards high quality products, game meat has earned much attention. The aim of the present work was to develop a DNA-based technique able to identify hare meat. Mitochondrial cytochrome b gene was used to design species-specific primers for hare detection. The new primers proved to be highly specific to Lepus species, allowing the detection of 0.01% of hare meat in pork meat by polymerase chain reaction (PCR). A real-time PCR assay with the new intercalating EvaGreen dye was further proposed as a specific and fast tool for hare identification with increased sensitivity (1 pg) compared to end-point PCR (10 pg). It can be concluded that the proposed new primers can be used by both species-specific end-point PCR or real-time PCR to accurately authenticate hare meat.
- Meat species identification by polymerase chain reaction technique to authenticate alheiras de caçaPublication . Santos, Cristina G.; Melo, Vítor S.; Amaral, Joana S.; Oliveira, Beatriz; Mafra, IsabelThe manufacture of traditional meat products is a long-established practice in the Northeast of Portugal, being Alheiras one of the most appreciated products. Alheiras are traditional smoked fermented sausages, mainly produced with pork and poultry meat in a mixture with bread and spices. Currently, game meat Alheiras (Alheiras de caça) are also available as very attractive meat products and prone to adulterations. To allow accurate information for consumers and avoid unfair competition among producers, it is important to develop efficient methodologies to assess meat species identification and verify the compliance with labelling.
- Meat species identification by polymerase chain reaction technique to authenticate Alheiras de caçaPublication . Santos, Cristina G.; Melo, Vítor S.; Amaral, Joana S.; Oliveira, Beatriz; Mafra, IsabelThe manufacture of traditional meat products is a long-established practice in the Northeast of Portugal, being Alheiras one of the most appreciated products. Alheiras are traditional smoked fermented sausages, mainly produced with pork and poultry meat in a mixture with bread and spices. Currently, game meat Alheiras (Alheiras de caça) are also available in the market being considered as very attractive meat products and prone to adulterations as they command higher prices compared to the common type of Alheiras. To allow accurate information for consumers and avoid unfair competition among producers, it is important to develop efficient methodologies to assess meat species identification and verify the compliance with labelling. For this purpose, several methods based either on proteins or DNA analyses have been suggested during the last decade.