Caracterización del crecimiento y comportamiento predictivo de especies de Eurotium en matriz de alimento balanceado

Los alimentos balanceados se caracterizan por tener bajos valores de actividad de agua. Sin embargo, la contaminación por hongos con especies de Eurotium es bastante común y causa agotamiento nutricional, deterioro y pérdidas económicas. El objetivo de este trabajo fue evaluar el crecimiento de Eurotium amstelodami, E. chevalieri, E. repens y E. rubrum en una matriz de alimento balanceado a diferentes condiciones de actividad de agua (0,71-0,97) y temperatura (5, 15, 25, 30 y 37 °C). Se determinó que las especies de Eurotium pueden crecer en un amplio rango de actividades de agua y temperatura en un corto período de tiempo (7 días), y a mayor velocidad que en medio sintético. Se utilizaron los modelos de Rosso y probabilísticos para determinar las condiciones de crecimiento limitantes y óptimas, así como la probabilidad de crecimiento en ciertas combinaciones de factores ambientales. Ambos modelos proporcionaron un ajuste preciso a los parámetros cardinales y una buena performance para los casos de crecimiento/sin crecimiento. Este es el primer trabajo que evalúa los parámetros de crecimiento de las especies de Eurotium directamente en alimento balanceado. Los datos obtenidos en el presente estudio son útiles para predecir y evitar el crecimiento de especies de Eurotium en este tipo de alimentos.Animal feeds are characterized by low water activity values. Nevertheless, fungal contamination with Eurotium species are quite common, causing nutritional depletion, spoilage and economic losses. The aim of this work was to assess Eurotium amstelodami, E. chevalieri, E. repens and E. rubrum growth in a feed matrix at different conditions of water activity (0.71–0.97) and temperature (5, 15, 25, 30 and 37 °C). It was found that Eurotium species are able to grow in a wide range of water activity and temperature in a short period of time (7 days) and faster than in synthetic media. Rosso and probabilistic models were applied in order to determine the limiting and optimum growth conditions as well as growth probability at certain combinations of environmental factors. Both models provided an accurate fit to the cardinal parameters and good performance for growth/no growth cases. This is the first report assessing the growth parameters of Eurotium species directly in animal feed. Data obtained in the present study is useful to predict and avoid Eurotium species growth in animal feed.Fil: Greco, Mariana Vanesa. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Micología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pose, Graciela Noemi. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Micología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pardo, Alejandro Guillermo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Micología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Mycoflora and Natural Incidence of Selected Mycotoxins in Rabbit and Chinchilla Feeds

Mycotoxins are secondary metabolites produced by filamentous fungi that cause a toxic response when ingested by animals or man. Demand of natural fur, such as those from rabbit and chinchilla, produced under controlled conditions, has increased worldwide. The toxicogenic mycoflora contaminating feeds for these animals was enumerated and identified. Six of the major mycotoxins implicated in animal mycotoxicosis were detected and quantified. Moulds count ranged from <10 to 4.7 × 105 CFU g−1; 14% of the samples exceeded the limit that determines hygienic feed quality. More than twenty species belonging to the five most important mycotoxigenic mould genera were recovered. Among the analyzed mycotoxins, aflatoxins were recovered in 100% of the examined samples, deoxynivalenol in 95%, fumonisins in 100%, ochratoxin A in 98%, T2 toxin in 98%, and zearalenone in 100%. Cooccurrence of mycotoxins was observed in 100% of the samples analyzed. Exposure to multiple mycotoxins was thus demonstrated for these animals

Mycoflora and natural incidence of selected mycotoxins in rabbit and chinchilla feeds

Mycotoxins are secondary metabolites produced by filamentous fungi that cause a toxic response when ingested by animals or man. Demand of natural fur, such as those from rabbit and chinchilla, produced under controlled conditions, has increased worldwide. The toxicogenic mycoflora contaminating feeds for these animals was enumerated and identified. Six of the major mycotoxins implicated in animal mycotoxicosis were detected and quantified. Moulds count ranged from < 10 to 4.710 5 CFU g-1; 14 of the samples exceeded the limit that determines hygienic feed quality. More than twenty species belonging to the five most important mycotoxigenic mould genera were recovered. Among the analyzed mycotoxins, aflatoxins were recovered in 100 of the examined samples, deoxynivalenol in 95, fumonisins in 100, ochratoxin A in 98, T2 toxin in 98, and zearalenone in 100. Cooccurrence of mycotoxins was observed in 100 of the samples analyzed. Exposure to multiple mycotoxins was thus demonstrated for these animals.Facultad de Ciencias Veterinaria

Toxigenic Alternaria species from Argentinean blueberries

Blueberries are traditionally consumed in North America, some European countries and Japan. In Argentina, the blueberry crop is profitable because production starts in November, when the northern hemisphere lacks fresh fruit. Fungal contaminants can grow and produce mycotoxins in fresh fruit. The aims of this work were to identify the main genera of the mycobiota of blueberries grown in Argentina and to determine the toxicogenic potential, pathogenicity and host specificity of the species isolated. The genus Alternaria was the main component of the blueberry mycobiota (95%); minor proportions of Phoma spp. (4%) and Penicillium spp. (1%) were also isolated. According to their sporulation patterns, 127 Alternaria isolates belonged to the Alternaria tenuissima species-group, 5 to the Alternaria alternata species-group and 2 to the Alternaria arborescens species-group. The last mentioned species-group was not isolated at 5. °C. Of the 134 isolates, 61% were toxicogenic in autoclaved rice; 97% of these produced alternariol (AOH) in a range from 0.14 to 119.18. mg/kg, 95% produced alternariol methylether (AME) in a range from 1.23 to 901.74. mg/kg and 65% produced tenuazonic acid (TA) in a range from 0.13 to 2778. mg/kg. Fifty two isolates co-produced the three mycotoxins. According to the size of the lesion that they caused on blueberries, the isolates were classified as slightly pathogenic, moderately pathogenic and very pathogenic. No significant differences in pathogenicity were found on different blueberry varieties.In this work, high incidence and toxicogenic potential of the Alternaria isolates from blueberries were demonstrated. Thus, more studies should be done to evaluate the health risk posed by the presence of the Alternaria toxins in blueberries and in the manufactured by-products.Fil: Greco, Mariana Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; ArgentinaFil: Patriarca, A.. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnologia. Area Ingenieria en Alimentos. Laboratorio de Microbiologia de Alimentos; ArgentinaFil: Terminiello, Laura Adriana. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnologia. Area Ingenieria en Alimentos. Laboratorio de Microbiologia de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fernández Pinto, Virginia Elena. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnologia. Area Ingenieria en Alimentos. Laboratorio de Microbiologia de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pose, Graciela Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; Argentin

Mycotoxins and mycotoxigenic fungi in poultry feed for food-producing animals

Moulds are capable of reducing the nutritional value of feedstuff as well as elaborating several mycotoxins. Mycotoxin-contaminated feed has adverse effects on animal health and productivity. Also, mycotoxins may be carried over into meat and eggs when poultry are fed with contaminated feed. In a point prevalence study feedstuff used for poultry nutrition in Argentina was analyzed for fungal flora, natural incidence of selected mycotoxins, and nutritional quality. Ten mould genera were recovered, six of them known to be mycotoxigenic. More than 28 species were determined. Fumonisins were detected in all the samples (median 1,750 ppb). Forty-four out of 49 samples (90%) were contaminated with DON (median 222 ppb) and OTA (median 5 ppb). Also, 44 out of 49 samples were contaminated with aflatoxins (median 2.685 ppb), 42 samples (86%) with ZEA (median 50 ppb), and 38 samples (78%) with T2-toxin (median 50 ppb). Ninety percent of the samples had at least one type of nutritional deficiency. This study indicates the need for continuous assessment of the mycological status of animal feed production, in order to feed animals for optimal performance ensuring food safety.Facultad de Ciencias Veterinaria

Mycotoxins and mycotoxigenic fungi in poultry feed for food-producing animals

Moulds are capable of reducing the nutritional value of feedstuff as well as elaborating several mycotoxins. Mycotoxin-contaminated feed has adverse effects on animal health and productivity. Also, mycotoxins may be carried over into meat and eggs when poultry are fed with contaminated feed. In a point prevalence study feedstuff used for poultry nutrition in Argentina was analyzed for fungal flora, natural incidence of selected mycotoxins, and nutritional quality. Ten mould genera were recovered, six of them known to be mycotoxigenic. More than 28 species were determined. Fumonisins were detected in all the samples (median 1,750 ppb). Forty-four out of 49 samples (90%) were contaminated with DON (median 222 ppb) and OTA (median 5 ppb). Also, 44 out of 49 samples were contaminated with aflatoxins (median 2.685 ppb), 42 samples (86%) with ZEA (median 50 ppb), and 38 samples (78%) with T2-toxin (median 50 ppb). Ninety percent of the samples had at least one type of nutritional deficiency. This study indicates the need for continuous assessment of the mycological status of animal feed production, in order to feed animals for optimal performance ensuring food safety.Facultad de Ciencias Veterinaria

Mycoflora and natural incidence of selected mycotoxins in rabbit and chinchilla feeds

Mycotoxins are secondary metabolites produced by filamentous fungi that cause a toxic response when ingested by animals or man. Demand of natural fur, such as those from rabbit and chinchilla, produced under controlled conditions, has increased worldwide. The toxicogenic mycoflora contaminating feeds for these animals was enumerated and identified. Six of the major mycotoxins implicated in animal mycotoxicosis were detected and quantified. Moulds count ranged from < 10 to 4 . 7 × 1 0 5 CFU g−1; 14% of the samples exceeded the limit that determines hygienic feed quality. More than twenty species belonging to the five most important mycotoxigenic mould genera were recovered. Among the analyzed mycotoxins, aflatoxins were recovered in 100% of the examined samples, deoxynivalenol in 95%, fumonisins in 100%, ochratoxin A in 98%, T2 toxin in 98%, and zearalenone in 100%. Cooccurrence of mycotoxins was observed in 100% of the samples analyzed. Exposure to multiple mycotoxins was thus demonstrated for these animals.Fil: Greco, Mariana Vanesa. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pardo, Alejandro Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; ArgentinaFil: Ludemann, Vanesa. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Martino, Pablo Eduardo. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Pose, Graciela Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; Argentina. Universidad Nacional de Río Negro; Argentin

Effect of water activity and temperature on the growth of Eurotium species isolated from animal feeds

Antecedentes: Los hongos xerófilos son un problema importante debido a su capacidad de crecer a bajas actividades del agua, lo que causa el deterioro de alimentos a humedades bajas e intermedias, de materias primas almacenadas y de piensos para animales, con las consecuentes pérdidas económicas. Objetivos: Se llevó a cabo un estudio sobre el efecto de los factores ambientales (temperatura y actividad del agua) sobre el crecimiento de cuatro especies pertenecientes al género Eurotium aisladas de piensos para animales. Métodos: Se estudió el crecimiento de Eurotium amstelodami, Eurotium chevalieri, Eurotium repens y Eurotium rubrum a valores de actividad de agua en el rango 0,710-0,993 en el medio de cultivo agar extracto de malta modificado con glicerol, y valores de temperatura de 5, 15, 25, 37 y 45 °C. Resultados: El modelo cardinal propuesto por Rosso y Robinson (2001) se aplicó para realizar el ajuste de datos con la actividad del agua como variable a una temperatura fija; se obtuvieron tres valores cardinales de actividad del agua (awmin, awmax, awopt) y la tasa de crecimiento específico en el valor óptimo de aw (μopt). También se aplicó un modelo probabilístico para definir la interfase entre crecimiento y no crecimiento. El modelo cardinal presentó una adecuada estimación del awopt y la máxima velocidad de crecimiento. El modelo probabilístico fue adecuado para el ajuste de los casos de crecimiento/falta de crecimiento en el rango previsto. Conclusiones: Los resultados presentados en este artículo pueden aplicarse para pronosticar el crecimiento de especies de Eurotium en piensos para animales.Background: Xerophilic fungi represents a serious problem due to their ability to grow at low water activities causing the spoiling of low and intermediate moisture foods, stored goods and animal feeds, with the consequent economic losses.Aims: The combined effect of water activity and temperature of four Eurotium species isolated from animal feeds was investigated.Methods: Eurotium amstelodami, Eurotium chevalieri, Eurotium repens and Eurotium rubrum were grown at 5, 15, 25, 37 and 45°C on malt extract agar adjusted with glycerol in the range 0.710?0.993 of water activities.Results: The cardinal model proposed by Rosso and Robinson (2001) was applied to fit growth data, with the variable water activity at fixed temperatures, obtaining three cardinal water activities (awmin, awmax, awopt) and the specific growth rate at the optimum aw (opt). A probabilistic model was also applied to define the interface between growth and no-growth. The cardinal model provided an adequate estimation of the optimal aw to grow and the maximum growth rate. The probabilistic model showed a good performance to fit growth/no-growth cases in the predicted range.Conclusions: The results presented here could be applied to predict Eurotium species growth in animal feeds.Fil: Greco, Mariana Vanesa. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Micología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pardo, Alejandro Guillermo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Micología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pose, Graciela Noemi. Universidad Nacional de Rio Negro. Sede Alto Valle. Escuela de Producción, Tecnología y Medio Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Patriarca, Andrea Rosana. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Conidial production by Penicillium nalgiovense for use as starter cultures in dry fermented sausages by solid state fermentation

Penicillium nalgiovense is the typical species used as starter culture on the casing of dry fermented sausages and it has been often produced by solid state fermentation (SSF). Soy beans, maize kernels and wheat bran (WB) at 50% humidity were tested as substrates in SSF for conidial production and viability in P. nalgiovense. Among them WB was the best substrate for conidial production and viability. Thus, WB proved to be a suitable and convenient choice for conidial production by P. nalgiovense in SSF. By analysing conidial production on different membranes in malt extract agar (MEA) and WB no differences were observed between different treatments for the same substrate. Therefore, the practical choice of the inert support seems to be filter paper. A natural substrate like WB together with membranes as support helped the production of viable conidia by SSF as starters for dry fermented sausages

Distribution of Xanthomonas arboricola pv. juglandis and Alternaria species-groups populations associated with brown apical necrosis at different phenological stages of walnut trees

Walnut (Juglans regia) can be affected by several diseases. Among them, walnut blight (WB) which is caused by the bacterium Xanthomonas arboricola pv. juglandis (Xaj) and brown apical necrosis (BAN) which has lately become economically significant causing crop losses in recent years. BAN can be considered as a complex disease in which, besides Xaj, the fungal genera Fusarium and Alternaria could be also involved. The objective of the present work was to determine the occurrence of Xaj and Alternaria sp.-grps. at different phenological stages of walnut in order to provide knowledge about the epidemiological aspects of BAN. Xaj was detected at 9 of the 11 phenological stages under study and Alternaria at all stages. No Fusarium isolates were detected at any stage. Buds were the main hibernation site for the bacterium which showed higher epiphytic concentrations than isolates of Alternaria. However, the fungus was more frequently found at all phenological stages until fruit set. On diseased fruits, the bacterium was predominant and the fungus was only found sporadically. This work provides knowledge that can contribute to the improvement of preventive programs such as control strategies that consider the weather forecasts and the phenology of walnut instead of strategies based on fix calendars.Fil: Marangi, María Julia. Universidad Nacional de Rio Negro. Centro de Investigaciones y Transferencia de Rio Negro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Rio Negro; ArgentinaFil: Temperini, Carolina Virginia. Universidad Nacional de Rio Negro. Centro de Investigaciones y Transferencia de Rio Negro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Rio Negro; ArgentinaFil: Greco, Mariana Vanesa. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pardo, Alejandro Guillermo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pose, Graciela Noemi. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; Argentin