Biocontrol activities of yeasts or lactic acid bacteria isolated from Robusta coffee against Aspergillus carbonarius growth and ochratoxin A production in vitro.

Biocontrol Agents (BCAs) can be an eco-friendly alternative to fungicides to reduce the contamination with mycotoxigenic fungi on coffee. In the present study, different strains of bacteria and yeasts were isolated from Ivorian Robusta coffee. Their ability to reduce fungal growth and Ochratoxin A (OTA) production during their confrontation against Aspergillus carbonarius was screened on solid media. Some strains were able to reduce growth and OTA production by 85 % and 90 % and were molecularly identified as two yeasts, Rhodosporidiobolus ruineniae and Meyerozyma caribbica. Subsequent tests on liquid media with A. carbonarius or solely with OTA revealed adhesion of R. ruineniae to the mycelium of A. carbonarius through Scanning Electron Microscopy, and an OTA adsorption efficiency of 50 %. For M. caribbica potential degradation of OTA after 24 h incubation was observed. Both yeasts could be potential BCAs good candidates for Ivorian Robusta coffee protection against A. carbonarius and OTA contamination.

Influence of Two Garlic-Derived Compounds, Propyl Propane Thiosulfonate (PTS) and Propyl Propane Thiosulfinate (PTSO), on Growth and Mycotoxin Production by Fusarium Species In Vitro and in Stored Cereals.

Two garlic-derived compounds, Propyl Propane Thiosulfonate (PTS) and Propyl Propane Thiosulfinate (PTSO), were examined for their efficacy against mycotoxigenic Fusarium species (F. graminearum, F. langsethiae, F. verticillioides). The objectives were to assess the inhibitory effect of these compounds on growth and mycotoxin production in vitro, and in situ in artificially inoculated wheat, oats and maize with one isolate of each respectively, at different water activity (aw) conditions when stored for up to 20 days at 25 °C. In vitro, 200 ppm of either PTS or PTSO reduced fungal growth by 50-100% and mycotoxin production by >90% depending on species, mycotoxin and aw conditions on milled wheat, oats and maize respectively. PTS was generally more effective than PTSO. Deoxynivalenol (DON) and zearalenone (ZEN) were decreased by 50% with 80 ppm PTSO. One-hundred ppm of PTS reduced DON and ZEN production in wheat stored at 0.93 aw for 20 days, although contamination was still above the legislative limits. Contrasting effects on T-2/HT-2 toxin contamination of oats was found depending on aw, with PTS stimulating production under marginal conditions (0.93 aw), but at 0.95 aw effective control was achieved with 100 ppm. Treatment of stored maize inoculated with F. verticilliodies resulted in a stimulation of total fumonsins in most treatments. The potential use of such compounds for mycotoxin control in stored commodities is discussed.

Rapid throughput analysis of filamentous fungal growth using turbidimetric measurements with the Bioscreen C: a tool for screening antifungal compounds.

A rapid method for screening antifungal compounds and performing ecophysiological studies with filamentous fungi has been developed by the use of specific semi-solid media and spectrophotometric/turbidimetric measurements using the Bioscreen C with 2×100 microtitre well plates. The medium composition and preparation, inoculum size, medium volumes, and incubation parameters for measuring initial germination and growth dynamics have been optimised. These have been applied to assess the effectiveness of 18 concentrations of propyl propane thiosulfinate (PTS) against Aspergillus flavus in YES medium under different environmental regimes. Minimum inhibitory concentrations (MIC), and non-inhibitory concentration (NIC) values, and a newly developed MIC(50), have been calculated for the efficacy of these concentrations of PTS under four different environmental conditions (0.995 and 0.95 water activity (a(w)); 20 and 25°C) over 7d periods with automated measurements every 20 min. Data were modelled using the Lambert-Pearson Model, a mathematical modelling approach previously used for bacterial inhibition. Results have been compared with traditional growth rate data and Lethal Dose(50) (LD(50)) values. This approach could have major implications for rapid screening assays for growth and secondary metabolite production by filamentous organisms and has major advantages in terms of time reduction, culture medium volumes required, measurement and the ability to integrate and model key parameters for comparing efficacy.

Bee pollen, a substrate that stimulates ochratoxin A production by Aspergillus ochraceus Wilh.

The capacity of bee pollen as a substrate for production of ochratoxin A (OTA) by a strain of Aspergillus ochraceus was studied. For control purposes corn, wheat and rice grains, and eleven liquid media were assayed. They were Yeast Extract Sucrose broth (YES), YES supplemented with 0.05, 0.1, 0.5, 1 and 5% bee pollen, YES supplemented with 0.5% peptone, 50% must, Wickerham medium, Aflatoxin Production medium and Coconut Broth Medium. Cultures were maintained at 28 degrees C for 4 weeks and were analyzed every seven days for OTA by liquid chromatography with fluorescence detection. OTA production in bee pollen was significantly (P < 0.01) higher than production in corn, wheat and rice grains regardless of incubation time. With regard to liquid cultures, OTA accumulation in YES supplemented with 5% bee pollen was significantly higher than in pollen-free liquid cultures. A positive correlation between the proportion of pollen added to YES medium and OTA level was observed. This is the first report concerning the use of bee pollen as a substrate to stimulate OTA production. On the basis of the preliminary results obtained in this study it can be hypothesized that bee pollen may constitute an important risk factor concerning the presence of OTA in the diet of consumers of that nutritious food.

Efectos antilipidémicos de un preparado de aceite de hígado de bacalao en 40 pacientes con dislipidemias

Estudiamos el efecto de un preparado nacional de aceite de hígado de bacalao a dosis de 14G. por día, en 40 pacientes con dislipidemias, y comparamos con un placebo en un estudio simple ciego abierto durante dos meses de tratamiento. El efecto sobre los lípidos plasmáticos se documentó luego de un mes de una dieta estándard tipo II de la AHA. El colesterol disminuyó en el grupo tratado solamente en 3%, en tanto que los triglicéridos se redujeron en un 28%. El colesteroL HDL aumentó 15% con el tratamiento. Estos resultados se obtuvieron luego dela reducción que produjo la administración de la dieta, la cual también provocó disminuciones que variaron entre un 6-15% para el colestero y los triglicéridos respectivamente. La tolerancia al preparado administrado en forma de suspensión fue excelente en la mayoría de los pacientes