Management and mitigation strategies for mycotoxins: the biological solutions

ICFC 2017 - International Conference on Food Contaminants (Book of Abstracts)Mycotoxins are toxic secondary metabolites produced by fungi that are found worldwide in many food products. They are a diverse group of chemical compounds that possess a multiplicity of toxic properties and affect human and farm animal health. Additionally, they cause significant economic losses. The problem of mycotoxins results mainly from fungal growth on crop cultures at the pre - or post - harvest stages. Implicated fungi belong mostly to Aspergillus , Penicillium , Fusarium , Alternaria and Claviceps genera. For these reasons, mycotoxins presence in foods should be monitored, and their levels reduced as low as technologically possible. In recent years , several biological solutions have been studied and developed to mitigate the adverse effects of myco toxins. These strategies can be divided into three main type of action: i) Biocontrol, in this case, defined as the control of mycotoxigenic fungal growth by other microorganisms; ii) Adsorption, which refers to the use of microorganism cells to bind mycot oxins; and iii) Biotransformation, when microorganisms or pure enzymes are used to degrade or transform mycotoxins into non - toxic compounds. This presentation will revise some of the main achievements done in this field in the last years and present the wo rk done at the Centre of Biological Engineering related to this thematic. Presented topics will include: i) The inhibition of Aspergillus flavus and Penicillium nordicum growth, as the production of aflatoxins and ochratoxin A by lactic acid bacteria and t heir organic acids; ii) The adsorption of mycotoxins by microorganisms isolated from Kefir grains; and iii) The biodegradation of ochratoxin A by Pediococcus parvulusUMINHO/BPD/51/2015 from project UID/BIO/04469/2013 financed by FCT/MEC (OE). This study was supported by FCT under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684); of BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded y European Regional Development Fund under the scope of Norte2020 -Programa peracional Regional do Norte; and under the scope of the projects RECI/BBB-BI/0179/2012 (FCOMP-01-0124-FEDER-027462)info:eu-repo/semantics/publishedVersio

Micotoxinas em vinhos: ocorrência e métodos analíticos

As micotoxinas são metabolitos secundários tóxicos produzidos por certos fungos filamentosos que apresentam efeitos teratogénicos, citotóxicos, neurotóxicos, nefrotóxicos, imunossupressores e/ou estrogénicos. Para além disso, algumas delas são comprovadamente cancerígenas aflatoxinas, ocratoxina A e fumonisinas estão classificadas respetivamente nos grupos 1, 2B e 2B pelo IARC [1]. As micotoxinas podem ser encontradas numa grande diversidade de produtos agrícolas e alimentares, o que constitui uma ameaça para a segurança alimentar. A sua ocorrência nestes produtos deve ser monitorizada e os seus níveis reduzidos tanto quanto tecnologicamente é possível de forma a minimizar o seu impacto na saúde humana. Nos vinhos, a ocratoxina A é a micotoxina mais comum e a única a estar legislada. No entanto, também tem sido reportada a presença de aflatoxina B2 [2], fumonisina B2 [3], alternariol e alternariol monometil éter [4-7], ácido tenuazónico [8], ácido ciclopiazónico, ácido micofenólico e zearalenona [9] em alguns vinhos. Embora a sua ocorrência não levante para já grandes problemas para a saúde dos consumidores, é importante que os produtores de vinho estejam atentos a esta problemática de forma a implementarem medidas de controlo adequadas. A presente comunicação pretende rever a problemática das micotoxinas nos vinhos de forma a divulgar os mais recentes progressos ocorridos nesta matéria. Uma revisão sobre a ocorrência de novas micotoxinas nos vinhos, métodos analíticos e sobre práticas que podem promover a segurança micotoxicológica dos vinhos irá ser apresentada

O incumprimento do contrato de trabalho imputável ao trabalhador numa perspetiva não disciplinar

O incumprimento do contrato de trabalho imputável ao trabalhador pode gerar responsabilidade disciplinar e responsabilidade civil. Deste modo, o trabalhador pode ser responsabilizado pelos danos que causar ao empregador em virtude de violação do contrato de trabalho. Existem duas modalidades de incumprimento do contrato de trabalho potencialmente geradoras de responsabilidade civil: Tipificadas no Código do trabalho e resultantes da regra geral prevista no art. 323º, nº1 do Código do trabalho

Degradation of ochratoxin A by proteases and by a crude enzyme of aspergillus niger

Ochratoxin A is a mycotoxin present in food commodities as cereals, wine, coffee, figs, dried vine fruits or beer and in feeds for animals. The enhancement of its conversion into ochratoxin a is considered to be a way to reduce its presence in the body and, therefore, its toxicity. In this paper we report the ability of several commercial proteases to hydrolyze ochratoxin A into ochratoxin a in different amounts. After an incubation period of 25 h., a significant hydrolytic activity at pH 7.5 for Protease A (87.3%), and for Pancreatin (43.4%) was detected. At pH 3.0, a weak hydrolytic activity was detected for Prolyve PAC (3%). None of the other commercial enzymes tested were able to hydrolyze ochratoxin A in the tested conditions. Also, the isolation of an enzyme extract from an Aspergillus niger strain with very strong ochratoxin A hydrolytic activity at pH 7.5 (99.8%) is reported. This activity is similar to the activity detected in Protease A. Data about the inhibition effect of ethylenediaminetetraacetic acid and phenylmethanesulfonyl fluoride on the involved hydrolytic enzymes showed that enzymes involved in ochratoxin A hydrolysis are metalloproteins.Fundação para a Ciência e a Tecnologia (FCT

Ecology of mycotoxin producing fungi present in wine grapes

In order to establish the potencial mycotoxin producer species hazardous for wine quality, surveys of filamentokis fungi were made in Portuguese wine grapes. These studies were conducted from 1999 to 2002, and are still ongoing. Among the more relevant fungi detected in grapes are black aspergilli, namely A. niger aggregate and A. carbo;arius, found to be responsible for the production of ochratoxin A in grapes. The results of these studies are discussed in an ecological point of view, and in terms of risk assessment for mycotoxins presence in the final product, wine.info:eu-repo/semantics/publishedVersio

Micotoxinas no vinho: problemas e soluções

Financiado pelo FEDER através do COMPETE e pela FCT (Ref. FCOMP-01-0124-FEDER-028029 e PTDC/AGR-TEC/3900/2012, respetivamente). Incentivo/EQB/LA0023/2014 do programa ON.2 – O Novo Norte

Validation of a SPE clean-up method for ochratoxin A determination in red wine

ICFC 2017 - International Conference on Food Contaminants (Book of Abstracts)The quality of Portuguese wines has improved considerably during the last decades as modern viticulture and enological practices were adopted. To maintain high quality standards it is also important to control any hazard that may jeopardize wine safety. On e potential hazard for wines is the occurrence of the mycotoxin, ochratoxin A (OTA). This fungal metabolite occurs and exerts its toxic effects in small quantities, thus sensitive and reliable methods are required for monitoring its occurrence in foods. In order to minimize the interfering effect of the matrix and improve the selectivity and sensitivity of the analytical method, a concentration and cleaning step is often necessary. Solid phase extraction (SPE) is a technique with numerous advantages for that purpose. The objective of this work was to optimize and validate an analytical method for the determination of OTA in red wine using the SPE column Strata-X-A (Phenomenex). A not contaminated local red wine was fortified with OTA at concentrations of 0.0 5 to 10 μg/L, samples were clean - up using Strata - X - A columns in triplicate, analyzed by HPLC with fluorescence detection, and method recoveries, selectivity, stability, linearity, limit of detection (LOD), and limit of quantification (LOQ) determined. The method showed a linear response within the concentration range of 0.05 to 10 μg/L with a correlation coefficient of 0.9999. Within this concentration range, recoveries varied between 111% and 87%, respectively. The intra - day RSD was below 8%. The LOD and LO Q of the method was 0.005 and 0.015 μg/L, respectively. Portuguese red wines were analyzed using this method. Four wines did not reveal any OTA, and seven add OTA in concentrations that ranged between 0.02 and 0.441 μg/L. In conclusion, 20 years after the first studies reporting the presence of OTA in wines, levels of this mycotoxin in Portuguese wines are still lowinfo:eu-repo/semantics/publishedVersio

Mycotoxigenic fungi in Portuguese wine regions : fumonisin B2 and ochratoxin A

Studies were conducted between 2001 and 2003 to evaluate the incidence of ochratoxigenic strains in Portuguese wine-grapes. At that time, the main responsible for ochratoxin A production in grapes were found to be Aspergillus carbonarius with a production mean of 1.13 mg/kg and some strains from the Aspergillus niger aggregate with a production mean of 0.14 mg/kg. At that time also, all the black aspergilli isolates were preserved in glycerol and stored at -80 ºC. Since recently A. niger was reported as a producer of the mycotoxin fumonisin B2, its levels produced by black aspergilli isolates from the Portuguese grapes were investigated. Approximately 29% of A. niger aggregate strains were found to produce it between 0.003–6.0 mg/kg with a mean of 0.66 mg/kg and only 6% produced more than 1 mg/kg. The incidence and distribution of fumonisinogenic strains among five Portuguese wine-regions is also presented and correlated with data of the ochratoxigenic ones.A incidência em Portugal de fungos filamentosos produtores de ocratoxina A em uvas para a produção de vinho foi avaliada entre os anos de 2001 a 2003. Nessa altura, o produtor mais frequente nas uvas foi a espécie Aspergillus carbonarius, com uma produção média em laboratório de 1,13 mg/kg, e algumas estirpes do agregado Aspergillus niger, com uma produção média em laboratório de 0,14 mg/kg. Todas as estirpes de Aspergillus negros então isoladas foram conservadas a -80 ºC. Recentemente, estirpes de Aspergillus niger foram descritas como produtores de fumonisina B2, pelo que a produção desta outra micotoxina foi verificada nas cerca de 700 estirpes conservadas. Aproximadamente 29% das estirpes do agregado A. niger produziram fumonisina B2, com produção em laboratório entre 0,003 a 6,0 mg/kg, sendo que apenas 6% produziram mais de 1 mg/kg. A incidência e a distribuição destas estirpes micotoxigénicas será apresentada e discutida.Fundação para a Ciência e a Tecnologia (FCT) - bolsa SFRH/BPD/43922/200

Biodegradation of Ochratoxin A by fungi isolated from grapes

Ochratoxin A is a mycotoxin present in several food products for which levels should be reduced. Chemical, physical, and biological methods have been proposed for the detoxification of mycotoxins, biological methods being the more promising ones. In this report, filamentous fungi isolated from Portuguese grapes were assessed for ochratoxin A degradation capabilities. It was observed that 51 of the 76 tested strains, predominantly aspergillus species, were able to degrade more than 80% of ochratoxin A added to the culture medium and that the most potent species (more than 95% of initial amount) were the black aspergilli, A. clavatus, A. ochraceus, A. versicolor, and A. wentii. Other fungi frequently isolated from grapes, such as Alternaria, Botrytis, Cladosporium, and Penicillium, also showed significant degradation capabilities. It was observed that the compounds obtained from the degradation of ochratoxin A by black aspergilli and by A. ochraceus and A. wentii strains were different.Fundação para a Ciência e a Tecnologia (FCT) - grant SFRH/ BD/1436/2000.Comunidade Europeia (CE) - Quality of Life Program (QoL), Key Action 1 (KA1) on Food, Nutrition and Health; contract number QLK1-CT-2001-01761-Wine-Ochra Risk