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The probability of growth and aflatoxin B 1 (AFB 1 ) production of 20 isolates of Aspergillus flavus were studied using a full factorial design with eight water activity levels (0.84–0.98 a w ) and six temperature levels (15–40 °C). Binary data obtained from growth studies were modelled using linear logistic regression analysis as a function of temperature, water activity and time for each isolate. In parallel, AFB 1 was extracted at different times from newly formed colonies (up to 20 mm in diameter). Although a total of 950 AFB 1 values over time for all conditions studied were recorded, they were not considered to be enough to build probability models over time, and therefore, only models at 30 days were built. The confidence intervals of the regression coefficients of the probability of growth models showed some differences among the 20 growth models. Further, to assess the growth/no growth and AFB 1 /no- AFB 1 production boundaries, 0.05 and 0.5 probabilities were plotted at 30 days for all of the isolates. The boundaries for growth and AFB 1 showed that, in general, the conditions for growth were wider than those for AFB 1 production. The probability of growth and AFB 1 production seemed to be less variable among isolates than AFB 1 accumulation. Apart from the AFB 1 production probability models, using growth probability models for AFB 1 probability predictions could be, although conservative, a suitable alternative. Predictive mycology should include a number of isolates to generate data to build predictive models and take into account the genetic diversity of the species and thus make predictions as similar as possible to real fungal food contamination. [ABSTRACT FROM AUTHOR]

Intraspecies variability in fungal growth and mycotoxin production has important implications for food safety. Using the Bioscreen C we have examined spectrophotometrically intraspecies variability of A . flavus using 10 isolates under different environments, including temperature shifts, in terms of growth and aflatoxin B 1 (AFB 1 ) production. Five high and five low AFB 1 producers were examined. The study was conducted at 5 isothermal conditions (from 15 to 37 °C) and 4 dynamic scenarios (between 15 and 30 °C). The experiments were carried out in a semisolid YES medium at 0.92 a w and two inoculum levels, 10 2 and 10 3  spores/mL. The Time to Detection (TTD) of growth initiation was determined and modelled as a function of temperature through a polynomial equation and the model was used to predict TTD under temperature upshifts conditions using a novel approach. The results obtained in this study have shown that a model can be developed to describe the effect of temperature upshifts on the TTD for all the studied isolates and inoculum levels. Isolate variability increased as the growth conditions became more stressful and with a lower inoculum level. Inoculum level affected the intraspecies variability but not the repeatability of the experiments. In dynamic conditions, isolate responses depended both on the temperature shift and, predominantly, the final temperature level. AFB 1 production was highly variable among the isolates and greatly depended on temperature (optimum temperature at 30–35 °C) and inoculum levels, with often higher production with lower inoculum. This suggests that, from an ecological point of view, the potential isolate variability and interaction with dynamic conditions should be taken into account in developing strategies to control growth and predicting mycotoxin risks by mycotoxigenic fungi. [ABSTRACT FROM AUTHOR]

The popularity of herbal infusions is increasing in recent years, mainly because of their health benefits. There are few studies about macroelements and microelements in the different commercial herbal infusions present in the market. The aim of this study was to determine the concentration of some macroelements (Ca, K, Mg and Na) and microelements (Fe, Cu, Mn and Zn) in twenty samples of herbal infusions, and compare them with tea. Most of the relationships between the mineral elements were positive. The extraction rate was uniform for all the samples. By comparison with tea, the only significant difference was in Ca concentration, which was much lower in tea infusion. Also, as a whole, Mn concentration was much higher in tea. A wide variability was observed both in dry materials and in herbal infusions. The profile of mineral elements was similar in most samples and remained in the herbal infusions. K and Ca were the predominant macroelements, and Fe and Mn the predominant microelements. Fe was the least soluble, and Cu, Zn and Na the most soluble. [ABSTRACT FROM AUTHOR]

Antiviral properties of water and methanol extracts from Lentinus edodes, Boletus edulis and Pleurotus ostreatus were evaluated against herpes simplex virus type 1 (HSV-1). Pre-treatment of Vero cells with 75 mg·ml-1 water extracts before virus addition, inhibited 60% of the virus infection and its addition during the virus adsorption period inhibited it up to 80%. Moreover, the mushrooms water extracts were able to significantly inhibit the in vitro virus replication, showing the concentration of a substance required to reduce plaque number in Vero cells by 50% (IC50) values from 26.69 mg·ml-1 to 35.12 mg·ml-1. Methanol extracts exhibited a lower antiviral activity in all cases. In order to identify the type of compounds responsible for the antiviral activity, the low molecular weight (LMW) and high molecular weight (HMW) fractions were evaluated. The activity was found to correlate with the β-glucans present in the polysaccharide fractions, which showed higher antiviral activity than the complete water extracts except for B. edulis where other compounds (probably chitin-binding lectins) might have contributed to the observed activity. [ABSTRACT FROM AUTHOR]