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Aims The aim of this work was to use mathematical kinetic modelling to assess the combined effects of aW, pH, O2 availability and temperature on the growth rate and time to growth of Aspergillus fumigatus strains isolated from corn silage. Methods and Results A full factorial design was used in which two factors were assayed: pH and aW. The aW levels assayed were 0·80, 0·85, 0·90, 0·92, 0·94, 0·96, 0·98 and 0·99. The levels of pH assayed were 3·5, 4, 4·5, 5, 6, 7, 7·5 and 8. The assay was performed at normal oxygen tension at 25 and 37°C, and at reduced oxygen tension at 25°C. Two strains of A. fumigatus isolated from corn silage were used. Kinetic models were built to predict growth of the strain under the assayed conditions. The cardinal models gave a good quality fit for radial growth rate data. The results indicate that the environmental conditions which take place during silage production, while limiting the growth of most micro-organisms, would not be able to control A. fumigatus. Moreover, pH levels in silage, far from limiting its growth, are also close to its optimum. Carbon dioxide at 5% in the environment did not significantly affect its growth. Conclusions A need for a further and controlled acidification of the silage exists, as no growth of A. fumigatus was observed at pH 3·5, as long as the organoleptic characteristics of the silage are not much compromised. Significance and Impact of the Study Aspergillus fumigatus is one of the major opportunistic pathogens able to cause illness such as allergic bronchopulmonary aspergillosis, aspergilloma and invasive aspergillosis to rural workers. Exposure of animals to A. fumigatus spores can result in infections, particularly in those organs exposed to external invasion, such as the airways, mammary gland and uterus at birth. [ABSTRACT FROM AUTHOR]

A survey of fungal contamination and presence of aflatoxins (AFs) and fumonisins (FBs) in 30 feed samples collected from 10 tilapia farms during three seasons in Nayarit State, located in north-western Mexico, was carried out using ELISA as screening and High-Performance Liquid Chromatography (HPLC) as confirmatory method. Mycobiota includedAspergillus flavusandFusariumspp. AFs were detected in 63.3% of samples using ELISA, but confirmation by HPLC revealed that all samples were under the detection limit. Regarding to FBs, positive samples were detected using both methods, with 19 positive samples (60% of total) by ELISA and 14 positive samples (46.6% of total) by HPLC and levels ranging from 0.148 to 2.587 mg/kg. Correlation was observed between both methods (r =0.516,p =0.004) for FBs results. No sample exceeded the European maximum levels for any of the mycotoxins. Water activity of samples ranged from 0.345 to 0.655, suggesting that mycotoxin occurrence is probably related to raw material contamination. [ABSTRACT FROM AUTHOR]

Ochratoxin A (OTA) was analysed in composite samples of cereal-based baby foods, beer, breakfast cereals (corn- and rice and wheat-based), loaf bread, peanuts and pistachios. Foodstuffs were collected in hypermarkets and supermarkets from 12 cities in the Spanish region of Catalonia, and composite samples were prepared for analysis involving liquid–liquid extraction, followed by immunoaffinity column clean-up and HPLC with fluorescence detection. Consumption data for the selected foodstuffs were collected by means of a food-frequency questionnaire. The studied population was grouped by age in infants, children, adolescents and adults; and exposure to OTA through the specified foodstuffs, and through wine and coffee, was assessed. Exposure assessment was done through deterministic and probabilistic modelling of the contamination and consumption data. OTA occurrence and mean of positive samples (ng g−1 or ng ml−1, for beer) were the following: 8.7% and 0.233 in baby foods; 88.7% and 0.022 in beer; 2.8% and 0.728 in corn-based breakfast cereals; 25% and 0.293 in wheat-based breakfast cereals; 12.9% and 0.283 in loaf bread; 41.7% and 0.241 in peanuts; and 2.9% and 0.228 in pistachios. The median estimated daily intake of OTA through the foodstuffs by each age group were below the latest provisional tolerable daily intakes (PTDIs) of 17 and 14 ng kg−1 bw day−1 recommended by the European Food Safety Authority (EFSA) in 2006 and the Joint FAO/WHO Expert Committee on Food Additives (JECFA) in 2007, respectively, ranging from 1% and 2% of those values in adolescents and children, to 3% and 11% in adults and infants. [ABSTRACT FROM PUBLISHER]

Fumonisin B1 (FB1) and B2 (FB2) are mycotoxins produced by Fusarium verticillioides and F. proliferatum and common contaminants of cereal crops. The objectives of this study were to (1) study the occurrence of fumonisins in Catalonia (north-eastern region of Spain) and (2) assess the exposure of the Catalonian population to these mycotoxins. Contamination data was provided by a wide survey where 928 individual samples were pooled to analyse 370 composite samples. Fumonisins were extracted and purified using immunoaffinity columns and determined by HPLC with fluorescence detection. The raw consumption data came from a nutritional study specifically designed to assess the dietary intake of the main foodstuffs related to fumonisin contamination for all population age groups. In addition, two specific groups were selected with respect to maize consumption: immigrants and celiac sufferers. Contamination and consumption data were combined by simulation using an essentially parametric–parametric (P-P) method. The P-P method draws sampling values from distribution functions fitted to consumption and contamination datasets. Moreover, to quantify the accuracy and reliability of the statistical estimates, we built related confidence intervals using a Pseudo-Parametric bootstrap method. The results of this study show that fumonisins are commonly found in some commodities on the Catalonian market, such as beer, corn snacks and ethnic foods; however, the values were well below the permitted maximum EU levels. The most exposed group were infants followed by immigrants but, in all cases, they were below the TDI of 2 µg/kg bw/day. [ABSTRACT FROM AUTHOR]

Fumonisins occur mainly in maize and they produce alterations on sphingolipid metabolism, unbalancing the sphinganine (Sa)/sphingosine (So) ratio. This alteration has been proposed as a biomarker of fumonisin exposure. The objective of this study was to establish the urinary and plasmatic levels of Sa, So as well as the ratio Sa/So from a sample of the Catalonian (Spain) population exposed to fumonisins at low levels. Firstly, plasma and urinary Sa and So levels and the ratio Sa/So were compared between two population groups, and later urinary Sa and So levels from corn food consumers and a control group were monitored for 2 weeks under controlled intake of corn foods. Sa and So levels were determined in urine and blood samples using validated methods using HPLC with fluorescence detection. Significant differences were not found in urine samples when Sa/So ratios were compared from corn food consumers and non-consumers, while significant differences were found in urine and plasma samples, but evidence of the mechanism of action of fumonisins was not apparent. Through a time-course study we have narrowed down the day in which the maximum alteration of Sa/So ratio should be expected in humans. This paper reports some useful information to improve the design of studies to validate the ratio Sa/So as a possible biomarker of fumonisin exposure. [ABSTRACT FROM AUTHOR]

The mycotoxin deoxynivalenol (DON) is one of the most common contaminants of cereals worldwide, and its occurrence has been widely reported in raw foods and foodstuffs, around the European region, including Catalonia. In the present work, a stochastic methodology has been applied to accurately assess the exposure of the Catalonian population (Spain) to DON through food consumption. Raw contamination data was provided by a large survey conducted in this region, in addition to the raw consumption data from a nutritional study specifically designed to assess the dietary intake of the main foodstuffs related to DON contamination for all population age groups. Contamination and consumption data were combined by simulation using an essentially parametric (P-P) method. The P-P method draws sampling values from distribution functions fitted to consumption and contamination data sets. Moreover, to quantify the accuracy and reliability of the statistics estimates, we built the related confidence intervals using a pseudo-parametric bootstrap method. Considering the results drawn from the P-P simulation method, the Catalonian population should be expected to be exposed at moderated levels of deoxynivalenol, the infants and individuals with ethnic dietary patterns being the most exposed population groups [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the effect of some pre-harvest fungicides on growth and aflatoxin (AF) production of three Aspergillus flavus strains found in Capsicum powder. Each isolate, previously isolated from paprika, chilli and smoked paprika, was inoculated on yeast extract sucrose agar and on a 3% paprika extract agar medium supplemented with different fungicides and incubated at 20 and 30°C during 7 days. Growth measurements were obtained on days 3, 5 and 7, and the AF production was determined on day 7. The significance of the effects of the factors (strain, medium, temperature, time and fungicides) and their interaction over colony diameter and AF production was determined. Temperature constrained the effectiveness of fungicides in reducing growth, the fungicides being most effective at 20°C. The efficacy of the fungicides over AF production depended on the medium used and temperature. The most effective fungicides in inhibiting growth and AF production, regardless of the strain tested or applied conditions, were tebuconazole 25% and mancozeb 80% applied at a concentration of 0.75 and 3.5 g l−1, respectively. Care should thus be taken in the choice of a suitable fungicide because their effectiveness may depend on intra-specific variation and temperature. Moreover, it is necessary to take into account that the most efficient fungicide in reducing growth is not always the best choice for pre-harvest treatments because it may promote AF production. Thus, the best fungicide is the one that can simultaneous prevent growth and AF production. [ABSTRACT FROM AUTHOR]

A survey of the fungal contamination and occurrence of aflatoxins and ochratoxin A (OTA) in 50 pistachio nut samples collected from commercial stores around Catalonia (Spain) was carried out. Aspergillus flavus was found in 30% of samples, whereas Aspergillus section Nigri, Aspergillus ochraceus, and Penicillium verrucosum were found in 40%, 2% and 26% of samples, respectively. A total of 204 fungal isolates were obtained; 70.8% of A. flavus isolates were able to produce aflatoxin B1 and B2, whereas OTA production capacity was detected in 54.4% of the A. section Nigri biseriate isolates. Aflatoxins were detected in five samples (10% of total), all exceeding the maximum legal limit set for aflatoxin B1 (2 µg kg-1) or for total aflatoxins (4 µg kg-1), with one sample having a very high level of contamination (1134.5 µg kg-1). Only one sample of pistachio showed OTA contamination at 0.67 µg kg-1. Simultaneous contamination by aflatoxins and OTA was not observed in these samples. It was concluded that the frequency of aflatoxins and OTA contamination in pistachio samples available in the Spanish market is relatively low. Thus, no significant contribution to health risk should be expected from aflatoxin consumption through pistachios among healthy consumers. However, the existence of single samples with an extremely high aflatoxin concentration reinforces the need for effective prevention strategies in pistachio processing and commercialization. [ABSTRACT FROM AUTHOR]

This study was conducted to assess patulin exposure in the Catalonian population. Patulin levels were determined in 161 apple juice samples, 77 solid apple-based food samples and 146 apple-based baby food samples obtained from six hypermarkets and supermarkets from twelve main cities of Catalonia, Spain. Patulin was analysed by a well-established validated method involving ethyl acetate extraction and direct analysis by high-performance liquid chromatography (HPLC) with ultraviolet light detection. Mean patulin levels for positive samples in apple juice, solid apple-based food and apple-based baby food were 8.05, 13.54 and 7.12 µg kg-1, respectively. No samples exceeded the maximum permitted levels established by European Union regulation. Dietary intake was separately assessed for babies, infants and adults through a Food Frequency Questionnaire developed from 1056 individuals from Catalonia. Babies were the main group exposed to patulin, however no risk was detected at these levels of contamination. Adults and infants consumers were far from risk levels. Another approach to determine estimated exposure was conducted through Monte Carlo simulation that distinguishes variability in exposures from uncertainty of distributional parameter estimates. [ABSTRACT FROM AUTHOR]

The objective was to determine the effect of added sodium chloride, barley malt and sucrose on the stability of fumonisin B1 (FB1) present in corn flour. Two levels of both sodium chloride (0.4% and 2%) and barley malt (0.8% and 5%) were added to the unextruded corn flour, and six levels of sucrose (3-10%) were used. The addition of sucrose at the lowest salt content (0.4%) as well as salt, either at 0.4% or at 2%, led to a significant decrease of FB1 levels in extruded samples, whereas malt, either at 0.8% or at 5%, did not significantly affect FB1 stability. Decontamination rates depended on the concentrations of added ingredients and ranged from 2% to 92%. The greatest reductions in FB1 content were achieved with extrusion cooking with a high salt content, whilst the lowest reductions were the result of processing corn flour with low contents of both salt and sucrose. Salt at 2% was the most effective ingredient in reducing FB1 content of the final extruded food. [ABSTRACT FROM AUTHOR]

Aims: To evaluate the effect of Botrytis cinerea growth on ochratoxin A (OTA) production by Aspergillus carbonarius and degradation. Methods and Results: OTA-producing A. carbonarius and B. cinerea were grown on grape-like medium at 20°C for 7 days. Radii of colonies were daily recorded and OTA was analysed. In addition, each B. cinerea isolate was inoculated on grape-like synthetic nutrient medium (SNM) paired with each A. carbonarius isolate at a distance of 45 mm. Botrytis cinerea isolates were also grown in OTA-spiked SNM. Growth rates of B. cinerea and A. carbonarius were 20 and 7·5 mm day−1, respectively. The growth of the colonies of each species stopped when they contacted each other in paired cultures. OTA production by A. carbonarius in the contact area was affected by B. cinerea, but no clear trend was observed. All B. cinerea isolates showed to degrade between 24·2% and 26·7% of OTA from spiked SNM. Conclusions: The ecological advantage of B. cinerea, in terms of growth rate, vs. OTA-producing Aspergillus in some wine-growing regions and its ability to degrade OTA may explain the low levels of this toxin in noble wines. Significance and Impact of the Study: At determinate conditions, the presence of B. cinerea in grapes with A. carbonarius may help in reducing OTA accumulation. [ABSTRACT FROM AUTHOR]

Aims: To test the ability of Fusarium proliferatum strains isolated from Pinus pinea to synthesize fumonisin B1 (FB1) in pine nuts. Method and Results: Eleven strains were inoculated in moist sterile shelled pine nuts and whole pine nuts, and incubated for 28 days. Moist sterile maize was inoculated in parallel as an optimum substrate for FB1 production by Fusarium species. Conclusions: Six of the strains produced FB1 in shelled pine nuts, and two of them did so in whole pine nuts. Impact and Significance of the Study: F. proliferatum is able to grow and produce FB1 in the husk of pine nuts and the mycotoxin can be found in the nut once shelled. Consequently, FB1 may be an important hazard in pine nuts. [ABSTRACT FROM AUTHOR]

Aims: The aim of this study was to assess the opportunities of Penicillium expansum to develop and produce patulin in apples during cold storage and in the steps prior to processing of apple products. Methods and Results: Two lots of apples var. Golden with different ripeness degree were used. Half of each lot was fungicide treated. Apples were inoculated with P. expansum and stored at 1°C for 6 weeks. The extent of lesions and patulin accumulation both at the end of cold storage and after 3 days at 20°C were assessed. Short storage at 20°C aimed to simulate the transport and storage steps at room temperature before processing. Lesion size significantly increased during the storage at 20°C. An interaction between fungicide treatment and ripeness degree was found; efficiency of fungicide treatment was higher for ripe apples. Although lesions were evident after cold storage, no patulin was detected. Patulin was detected only when fruits were further stored at 20°C. Neither ripeness degree nor fungicide treatment affected patulin accumulation. Conclusions: Cold storage periods of 6 weeks do not lead to patulin accumulation. Significance and Impact of the Study: Shortening preprocessing times at warm temperatures would result into a reduction in patulin content at initial steps of fruits entering the processing plants. [ABSTRACT FROM AUTHOR]

The article presents a study which examined the effects of incubation time, especially at early growth stages, on mean ochratoxin A (OTA)-producing capacity and OTA accumulation by four Aspergillus carbonarius strains isolated from Spanish and Tunisian grapes. OTA accumulation starts earlier at high temperatures but increases slowly and becomes constant. The study concluded that OTA production and accumulation may happen in the temperature range of 15-30 degree Centigrade.

The antifungal effect of 20 essential oils against the most important moulds in terms of spoilage of bakery products (Eurotium spp., Aspergillus spp. and Penicillium spp.) was investigated. Suitable solutions of essential oils were added directly to an agar culture medium (containing 2% wheat flour) to obtain a final concentration in the range between 0 to 1,000ppm. Antifungal activity was tested at different water activity (aw) and pH conditions, and the fungal growth was followed by measuring the colony diameter during the incubation period. Only cinnamon leaf, rosemary, thyme, bay and clove essential oils exhibited some antifungal activity against all isolates. The antifungal activity depended on aw and pH levels. In general, a stronger inhibition was observed as the water availability increased, moreover, in some cases at 0.80 aw they favoured fungal growth. The interaction between essential oil concentration and pH depended mainly on the essential oil. Rosemary, thyme and bay were more effective at pH 5, loosing their activity as pH increased, while only cinnamon leaf was more effective near neutrality. These findings strengthen the possibility of using plant essential oils as an alternative to chemicals to preserve bakery products. [ABSTRACT FROM AUTHOR]

a. velluti, v. sanchis, a.j. ramos, c. turon and s. marín. 2004. The effect of five essential oils (oregano, cinnamon, lemongrass, clove and palmarose) on growth rate, zearalenone (ZEA) and deoxynivalenol (DON) production by Fusarium graminearum strains was assessed. The influence of the essential oils was tested on irradiated maize at two concentrations (500 and 1000 mg kg−1), at different water activity ( aw) (0·95 and 0·995) and temperature (20 and 30°C) levels. At 0·995 aw all essential oils tested had an inhibitory effect on growth rate of F. graminearum at both temperatures studied. At this aw level, DON production in general was inhibited by all essential oils at 30°C and, although palmarose and clove were the only essential oils with statistically significant inhibitory effect on ZEA production, an inhibitory trend was observed when cinnamon and oregano oils were added to maize grain. Antifungal and antimycotoxigenic activity of the essential oils assayed was shown to depend on environmental conditions. It is apparent that essential oils should be considered as alternative preharvest natural fungicides. Further investigation on natural maize grain might be useful to study the effectiveness of these essential oils in the presence of natural mycoflora of maize grain. [ABSTRACT FROM AUTHOR]

Fungal infection and ochratoxin A (OTA) contamination were determined in green coffee samples from different origins, in which OTA-producing fungi were also identified. About 72% of the beans analysed by direct plating presented fungal infection, including species of Aspergillus, Penicillium and Rhizopus. The genus Aspergillus was presented in more than 90% of infected coffee beans. Aspergillus ochraceus and Aspergillus section Nigri isolates represented 2.8 and 65.4%, respectively from the total number of isolates from the coffee beans. The capacity to produce OTA was determined in 260 isolates of A. section Nigri and 19 of A. ochraceus by the agar plug method, giving positive results for 6% of the A. section Nigri isolates and 16% of the A. ochraceus. OTA production was analysed by high performance liquid chromatography. OTA contamination of green coffee beans was analysed by enzyme immunoassay. OTA levels in all samples analysed were above the limit of detection (0.6 µg/kg), with a mean OTA concentration of 6.7 µg/kg. [ABSTRACT FROM AUTHOR]

n. bellí, a.j. ramos, v. sanchis and s. marín. 2003. The objective of this study was to determine the temporal ochratoxin A (OTA) accumulation profile of Aspergillus section Nigri at different water activity ( aw) levels. Two Aspergillus carbonarius and two Aspergillus niger aggregate strains isolated from grapes were tested in vitro for OTA accumulation at 25°C on synthetic nutrient medium, over periods of 20 days at different aw levels. Results were modelled by a multiple linear regression and response surface predictive models were obtained. High levels of aw favoured OTA production by these moulds. Maximum amounts of OTA were found at the earlier growth states (5 days for A. carbonarius and 7–13 days for A. niger aggregate). Provided that A. section Nigri, and mainly A. carbonarius, play the main role in OTA presence in grapes, it would be critical to adjust the harvest and processing time to significantly reduce the chances for OTA accumulation. Ochratoxin A production by A. section Nigri has been shown for the first time to occur optimally after as little as 5 days on a grape-like medium. [ABSTRACT FROM AUTHOR]

This work gives a general overview of ochratoxin A (OTA) occurrence in wines and the methodology for OTA analysis. The results of more than two thousand samples taken from the literature have been taken into account to quite extensively describe the present situation of OTA contamination of wine. According to these data, OTA is much more commonly detected in red wines than in rosé and white wines, and OTA concentration is remarkably higher than in the latter ones. Thus OTA could be detected in 45% (median 34%) of white wine samples, whereas it was detected in 66% (median 66%) of rosé and 71% (median 90%) of red wine samples. When comparing the wines from Northern and Southern regions, the latter showed a higher contamination than those from the Northern area. It has been suggested that OTA accumulation could be due to fungi belonging to the genus Aspergillus in wines from Southern European countries because the crops are exposed to elevated temperatures, which favour growth of OTA-producing Aspergillus species over Penicillium. High performance liquid chromatography (HPLC) associated with fluorescence detection preceded by extraction of OTA using commercially available immunoaffinity columns (IAC) is currently the most applied method for OTA determination in wines. [ABSTRACT FROM AUTHOR]

Apart from Eurotium species, Aspergillus and Penicillium isolates are common contaminants of bakery products. This paper deals with the use of weak-acid preservatives (potassium sorbate, calcium propionate, and sodium benzoate) to prevent spoilage by Aspergillus niger, A. flavus, and Penicillium corylophilum in analogs of a bakery product. A hurdle technology approach has been considered in which factors other than preservatives are pH and water activity. Potassium sorbate has been found to be the most effective in preventing fungal spoilage of this kind of products at the maximum concentration tested (0.3%). Suboptimal doses (0.03%) of all preservatives tested led to an enhancement of growth of Aspergillus and Penicillium isolates. The characteristics of the products involved must be carefully considered before making the decision of adding weak-acid preservatives; moreover, they must be added at the right concentrations. Furthermore, more research is needed on the use of alternative natural preservatives, such as essential oils. [ABSTRACT FROM AUTHOR]

This survey describes the fumonisin B[SUB1] (FB[SUB1]) occurrence in 228 and 58 corn-based food samples from Spain for human and animal consumption, respectively. High-performance liquid chromatography (HPLC) with ophthaldialdehyde derivatization was used for the analysis of FB[SUB1]. We detected FB[SUB1] in 86% of the samples for animal consumption, ranging from 89-8757 ng/g. Four of these samples had levels of FB[SUB1] > 5000 ng/g but none of them higher than 10,000 ng/g. On the other hand, FB[SUB1] was detected in 23% of the samples for human consumption. The lowest amount of FB[SUB1] found in a positive sample was 16 ng/g, and the highest was 938 ng/g. The most contaminated samples were the wholemeal corn flours, with a range of contamination that varied from 299-938 ng/g. [ABSTRACT FROM AUTHOR]

Examines the effect of modified atmosphere packaging and water activity on growth of Eurotium amstelodami, E. chevalier and E. herbariorum on a sponge cake analogue. Use of a multivariate statistical method; Interaction between carbon dioxide and oxygen; Correlation between carbon dioxide concentration in the bags and the lag phase.