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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 aim of this work was to assess the temporal relationship among quantified germination, mycelial growth and aflatoxin B 1 (AFB1) production from colonies coming from single spores, in order to find the best way to predict as accurately as possible the presence of AFB1 at the early stages of contamination. Germination, mycelial growth, probability of growth and probability of AFB1 production of an isolate of Aspergillus flavu s were determined at 25 °C and two water activities (0.85 and 0.87) on 3% Pistachio Extract Agar (PEA). The percentage of germinated spores versus time was fitted to the modified Gompertz equation for the estimation of the germination parameters (geometrical germination time and germination rate). The radial growth curve for each colony was fitted to a linear model for the estimation of the apparent lag time for growth and the growth rate, and besides the time to visible growth was estimated. Binary data obtained from growth and AFB1 studies were modeled using logistic regression analysis. Both water activities led to a similar fungal growth and AFB1 production. In this study, given the suboptimal set conditions, it has been observed that germination is a stage far from the AFB1 production process. Once the probability of growth started to increase it took 6 days to produce AFB1, and when probability of growth was 100%, only a 40–57% probability of detection of AFB1 production was predicted. Moreover, colony sizes with a radius of 1–2 mm could be a helpful indicator of the possible AFB1 contamination in the commodity. Despite growth models may overestimate the presence of AFB1, their use would be a helpful tool for producers and manufacturers; from our data 5% probability of AFB1 production (initiation of production) would occur when a minimum of 60% probability of growth is observed. Legal restrictions are quite severe for these toxins, thus their control from the early stages of contamination throughout the food chain is of paramount importance. [ABSTRACT FROM AUTHOR]

The objective of the present study was to assess the differences in modeled growth/AFB1 production probability and kinetic growth parameters for Aspergillus flavus inoculated as single spores or in a concentrated inoculation point (~ 500 spores). The experiment was carried out at 25 °C and at two water activities (0.85 and 0.87) on pistachio extract agar (3%). Binary data obtained from growth and AFB1 studies were modeled using linear logistic regression analysis. The radial growth curve for each colony was fitted to a linear model for the estimation of the lag phase for growth and the mycelial growth rate. In general, radial growth rate and lag phase for growth were not normally distributed and both of them were affected by the inoculation type, with the lag phase for growth being more affected. Changing from the multiple spore to the single spore inoculation led to a delay of approximately 3–5 days on the lag phase and higher growth rates for the multiple spore experiment were found. The same trend was observed on the probability models, with lower predicted probabilities when colonies came up from single spores, for both growth and AFB1 production probabilities. Comparing both types of models, it was concluded that a clear overestimation of the lag phase for growth occurred using the linear model, but only in the multiple spore experiment. Multiple spore inoculum gave very similar estimated time to reach some set probabilities (t10, t50 and t100) for growth or AFB1 production due to the abruptness of the logistic curve developed. The observed differences suggest that inoculum concentration greatly affects the outcome of the predictive models, the estimated times to growth/AFB1 production being much earlier for the concentrated inoculum than for a single spore colony (up to 9 days). Thus the number of spores used to generate data in predictive mycology experiments should be carefully controlled in order to predict as accurately as possible the fungal behavior in a foodstuff. [ABSTRACT FROM AUTHOR]

Human exposure to aflatoxins in foods is of great concern. The aim of this work was to use predictive mycology as a strategy to mitigate the aflatoxin burden in pistachio nuts postharvest. The probability of growth and aflatoxin B 1 (AFB1) production of aflatoxigenic Aspergillus flavus , isolated from pistachio nuts, under static and non-isothermal conditions was studied. Four theoretical temperature scenarios, including temperature levels observed in pistachio nuts during shipping and storage, were used. Two types of inoculum were included: a cocktail of 25 A . flavus isolates and a single isolate inoculum. Initial water activity was adjusted to 0.87. Logistic models, with temperature and time as explanatory variables, were fitted to the probability of growth and AFB1 production under a constant temperature. Subsequently, they were used to predict probabilities under non-isothermal scenarios, with levels of concordance from 90 to 100% in most of the cases. Furthermore, the presence of AFB1 in pistachio nuts could be correctly predicted in 70–81 % of the cases from a growth model developed in pistachio nuts, and in 67–81% of the cases from an AFB1 model developed in pistachio agar. The information obtained in the present work could be used by producers and processors to predict the time for AFB1 production by A . flavus on pistachio nuts during transport and storage. [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]

Ergosterol, ergosta7,22 dienol, ergosta 5,7 dienol, fungisterol, ergosta-4,7,2-trien-3-ona and ergosta-4,6,8(14),22-tetraen-3-ona were the fungal sterols detected in Agaricus bisporus mushrooms after optimization of a sterol extraction method. Their concentration ranged from 3.1 to 11.2mg/g dw depending on the strain, casing soil, flush number, developmental stage and sporophore tissue analyzed. Two methods were optimized to obtain sterol enriched extracts from A. bisporus fruiting bodies using pressurized liquid extraction (PLE) and supercritical fluid extraction (SFE). PLE using ethanol as solvent at 10.7MPa (50°C and 100°C) after 5cycles of 5min extraction (mixing in the extraction cell the sample with sand in a ratio 1:4) yielded extracts with respectively 5 and 2.9% sterols. Using SFE-CO2 at 40°C and 9 to 30MPa fractions containing 60% of sterols were obtained. Both technologies could be also utilized to extract sterols from mushroom by-products (the lower part of the stipe) as a method for their valorization. Industrial relevance: In this work, two environmentally friendly methods (SFE and PLE) to obtain sterol enriched fractions from Agaricus bisporus mushrooms were optimized. Extractions from both the complete fruiting body and the lower part of the stipe (usually discarded as a by-product during harvesting) yielded extracts with high ergosterol (and derivatives) content that could be used as functional ingredients to design novel foods with hypocholesterolemic properties since fungal sterols are able to reduce cholesterol levels in serum as plant phytosterols. Moreover, if the mushroom by-products are utilized as starting material, this application can be an interesting alternative method for the commercial valorization of this residue. [ABSTRACT FROM AUTHOR]

Inflammatory bowel disease (IBD) is a chronic, complex relapsing disorder characterised by immune dysregulation, gut microbiota alteration, and disturbed intestinal permeability. The diagnosis and the management of IBD are challenging due to the recurrent nature and complex evolution of the disease. Furthermore, the molecular mechanism underlying the aetiology and pathogenesis of IBD is still poorly understood. There is an unmet need for novel, reliable, and noninvasive tools for diagnosing and monitoring IBD. In addition, metabolomic profiles may provide a priori determination of optimal therapeutics and reveal novel targets for therapies. This review tries to gather scientific evidence to summarise the emerging contribution of metabolomics to elucidate the mechanisms underlying IBD and changes associated with disease phenotype and therapies, as well as to identify biomarkers with metabolic imbalance in those patients. Metabolite changes during health and disease could provide insights into the disease pathogenesis and the discovery of novel indicators for the diagnosis and prognosis assessment of IBD. Metabolomic studies in IBD have shown changes in tricarboxylic acid cycle intermediates, amino-acid and fatty-acid metabolism, and oxidative pathways. Metabolomics has made progress towards identifying metabolic alterations that may provide clinically useful biomarkers and a deeper understanding of the disease. However, at present, there is insufficient evidence evaluating the predictive accuracy of these molecular signatures and their diagnostic ability, which is necessary before metabolomic data can be translated into clinical practice. [ABSTRACT FROM AUTHOR]

Inflammatory bowel disease (IBD) is a chronic relapsing–remitting systemic disease of the gastrointestinal tract. It is well established that the gut microbiome has a profound impact on IBD pathogenesis. Our aim was to systematically review the literature on the IBD gut microbiome and its usefulness to provide microbiome-based biomarkers. A systematic search of the online bibliographic database PubMed from inception to August 2020 with screening in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was conducted. One-hundred and forty-four papers were eligible for inclusion. There was a wide heterogeneity in microbiome analysis methods or experimental design. The IBD intestinal microbiome was generally characterized by reduced species richness and diversity, and lower temporal stability, while changes in the gut microbiome seemed to play a pivotal role in determining the onset of IBD. Multiple studies have identified certain microbial taxa that are enriched or depleted in IBD, including bacteria, fungi, viruses, and archaea. The two main features in this sense are the decrease in beneficial bacteria and the increase in pathogenic bacteria. Significant differences were also present between remission and relapse IBD status. Shifts in gut microbial community composition and abundance have proven to be valuable as diagnostic biomarkers. The gut microbiome plays a major role in IBD, yet studies need to go from casualty to causality. Longitudinal designs including newly diagnosed treatment-naïve patients are needed to provide insights into the role of microbes in the onset of intestinal inflammation. A better understanding of the human gut microbiome could provide innovative targets for diagnosis, prognosis, treatment and even cure of this relevant disease. [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]

The importance of the gut microbiota in human health is currently well established. It contributes to many vital functions such as development of the host immune system, digestion and metabolism, barrier against pathogens or brain-gut communication. Microbial colonization occurs during infancy in parallel with maturation of the host immune system; therefore, an adequate cross-talk between these processes is essential to generating tolerance to gut microbiota early in life, which is crucial to prevent allergic and immune-mediated diseases. Inflammatory bowel disease (IBD) is characterized by an exacerbated immune reaction against intestinal microbiota. Changes in abundance in the gut of certain microorganisms such as bacteria, fungi, viruses, and archaea have been associated with IBD. Microbes that are commonly found in high abundance in healthy gut microbiomes, such as F. prausnitzii or R. hominis , are reduced in IBD patients. E. coli , which is usually present in a healthy gut in very low concentrations, is increased in the gut of IBD patients. Microbial taxa influence the immune system, hence affecting the inflammatory status of the host. This review examines the IBD microbiome profile and presents IBD as a model of dysbiosis.