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Abstract(s)
Os Bolores são organismos que crescem numa grande variedade de alimentos. Como são maioritariamente aeróbios, crescem preferencialmente à superfície do alimento em contato com o ar, pelo que a assimilação de nutrientes é bastante acelerada.
Muitos dos bolores que se desenvolvem nos alimentos produzem micotoxinas, nomeadamente Ocratoxina A (OTA), com elevado grau toxigénico.
Este trabalho teve como principal objetivo a identificação dos bolores e a deteção e quantificação de OTA em produtos cárneos curados com origem no Nordeste Transmontano, mais especificamente presuntos de suíno e presuntos de caprino. Foram assim, analisadas 91 amostras: 14 amostras de presunto de caprino e 77 de presunto de suíno, com diferentes tempos de cura.
Os bolores foram isolados em meio de cultura DG18 e DRBC e identificados por métodos fenotípicos e moleculares. A deteção e quantificação de OTA foram efetuadas por extração da micotoxina em solução aquosa de metanol, purificação por colunas de imunoafinidade e análise por Cromatografia Líquida de Alta Eficiência com Deteção por Fluorescência (HPLC-FLD).
Das amostras de presunto suíno, 15 apresentaram contaminação com OTA, sendo que 3 continham níveis de OTA bastante elevados, nomeadamente entre 25,4 μg/kg e 99,1 μg/kg. Em nenhuma das 14 amostras de presunto de caprino analisadas foi detetada contaminação com OTA.
No que se refere à caracterização da micobiota dos produtos em estudo, foram isolados 544 fungos filamentosos, dos quais foram identificados 172 fungos dos géneros Aspergillus e Penicillium, pertencentes a 12 espécies diferentes. Os fungos com maior prevalência nas amostras analisadas foram Aspergillus flavus e Penicillium commune. A. flavus teve uma prevalência de 50% em amostras de presunto de caprino e 31% em suíno. O P. commune teve uma prevalência de 25% em presunto de caprino e 60% em presunto de suíno.
Aspergillus westerdijkiae e Penicillium nordicum foram as únicas espécies identificadas como sendo produtoras de OTA. P. nordicum, fungo mais frequentemente associado a contaminação de produtos cárneos curados, apresentou prevalência bastante baixa, Provavelmente por se tratar de um fungo difícil de isolar na presença de outros microrganismos.
Molds are organisms that grow in a wide variety of foods. As they are mostly aerobic they preferably grow on the surface of food in contact with air, where the assimilation of nutrients is very rapid. Many of the molds that grow on foods produce mycotoxins, one example being Ochratoxin A (OTA), which shows a high toxigenic degree. This study aimed to identify the mycobiota and to detect and quantify of OTA in cured meat products originating in the Trás-os-Montes, more specifically pork and goat ham. A total of 91 samples were analysed: 14 samples of goat ham and 77 of pork ham with different curing times. Molds belonging to the genera Aspergillus and Penicillium were isolated in DG18 and DRBC culture media and the most representative isolates were identified to the species level by phenotypic and molecular methods. OTA detection and quantification were performed by extracting the mycotoxin with aqueous methanol, purification by immunoaffinity columns and analysis by High Performance Liquid Chromatography with Fluorescence Detection (HPLC-FLD). Among the pork ham samples, 15 were contaminated with OTA, and 3 contained very high levels of OTA, between 25.4 μg/kg and 99.1 μg/kg. None of the 14 samples of goat ham showed detectable levels of OTA. With regard to the mycobiota characterisation, 172 of the 544 isolated molds were identified. Twelve different species of Aspergillus and Penicillium were identified. The most prevalent fungi in the samples were Aspergillus flavus and Penicillium commune. A. flavus had a prevalence of 50% in samples of goat ham and 31% in pork ham. P. commune had a prevalence of 25% in goat ham and 60% in ham pork. Aspergillus westerdijkiae and Penicillium nordicum were the only species identified as OTA producers. P. nordicum most commonly associated with contamination of cured meat products showed very low prevalence, probably because its detection and isolation is very difficult when in the presence of other microorganisms.
Molds are organisms that grow in a wide variety of foods. As they are mostly aerobic they preferably grow on the surface of food in contact with air, where the assimilation of nutrients is very rapid. Many of the molds that grow on foods produce mycotoxins, one example being Ochratoxin A (OTA), which shows a high toxigenic degree. This study aimed to identify the mycobiota and to detect and quantify of OTA in cured meat products originating in the Trás-os-Montes, more specifically pork and goat ham. A total of 91 samples were analysed: 14 samples of goat ham and 77 of pork ham with different curing times. Molds belonging to the genera Aspergillus and Penicillium were isolated in DG18 and DRBC culture media and the most representative isolates were identified to the species level by phenotypic and molecular methods. OTA detection and quantification were performed by extracting the mycotoxin with aqueous methanol, purification by immunoaffinity columns and analysis by High Performance Liquid Chromatography with Fluorescence Detection (HPLC-FLD). Among the pork ham samples, 15 were contaminated with OTA, and 3 contained very high levels of OTA, between 25.4 μg/kg and 99.1 μg/kg. None of the 14 samples of goat ham showed detectable levels of OTA. With regard to the mycobiota characterisation, 172 of the 544 isolated molds were identified. Twelve different species of Aspergillus and Penicillium were identified. The most prevalent fungi in the samples were Aspergillus flavus and Penicillium commune. A. flavus had a prevalence of 50% in samples of goat ham and 31% in pork ham. P. commune had a prevalence of 25% in goat ham and 60% in ham pork. Aspergillus westerdijkiae and Penicillium nordicum were the only species identified as OTA producers. P. nordicum most commonly associated with contamination of cured meat products showed very low prevalence, probably because its detection and isolation is very difficult when in the presence of other microorganisms.