Occurrence of Aspergillus species in mixed feeds and component raw materials and their ability to produce ochratoxin A

Unveiling ochratoxin A and ochratoxigenic fungi in Brazilian artisanal Cheeses: Insights from production to consumption

Ochratoxin A (OTA) is a toxin produced by several Aspergillus species, mainly those belonging to section Circumdati and section Nigri. The presence of OTA in cheese has been reported recently in cave cheese in Italy. As artisanal cheese production in Brazil has increased, the aim of this study was to investigate the presence of ochratoxin A and related fungi in artisanal cheese consumed in Brazil. A total of 130 samples of artisanal cheeses with natural moldy rind at different periods of maturation were collected. Of this total, 79 samples were collected from 6 producers from Canastra region in the state of Minas Gerais, since this is the largest artisanal cheese producer region; 13 samples from one producer in the Amparo region in the state of São Paulo and 36 samples from markets located in these 2 states. Aspergillus section Circumdati occurred in samples of three producers and some samples from the markets. A. section Circumdati colony counts varied from 102 to 106 CFU/g. Molecular analysis revealed Aspergillus westerdijkiae (67 %) as the most frequent species, followed by Aspergillus ostianus (22 %), and Aspergillus steynii (11 %). All of these isolates of A. section Circumdati were able to produce OTA in Yeast Extract Sucrose Agar (YESA) at 25 °C/7 days. OTA was found in 22 % of the artisanal cheese samples, ranging from 1.0 to above 1000 µg/kg, but only five samples had OTA higher than 1000 µg/kg. These findings emphasize the significance of ongoing monitoring and quality control in the artisanal cheese production process to minimize potential health risks linked to OTA contamination.

Epiphytic microflora and mycotoxin content in meadows-Is plant biodiversity affecting fungal contamination?

Ecosystem services are an important aspect of grasslands utilization; however, they are often contradictory to their main purpose, which is a production of good quality and safe feed. In this study, we evaluated the difference between grass monocultures and species-rich mixtures in terms of epiphytic microflora and mycotoxin contamination levels. We hypothesized that higher species diversity would lead to higher microbial counts, which could lead to higher mycotoxin contamination risk. Differences in epiphytic fungal, yeast and total amount of microorganisms (CFU g -1) depending on the species diversity in the field has been evaluated by cultivation method. Concentration of deoxynivalenol (DON), zearalenone (ZEN) and aflatoxin B1 (AFB1) was measured by ELISA. Results are suggesting that higher total amount of microorganisms were found in monocultures, however, fungal and yeast counts were higher in species-rich mixtures. Higher species diversity of grasses was related to higher total microbial count (TMC) and yeast colonization of phyllosphere. Our results suggest higher risk of fungal phyllosphere colonization of species-rich mixtures with higher biodiversity and therefore higher risk of mycotoxin contamination of such feed.

Monitoring of Mycotoxigenic Fungi in Fish Farm Water and Fumonisins in Feeds for Farmed Colossoma macropomum

This study aimed to evaluate the occurrence of mycotoxigenic fungi in fish farm water and mycotoxins in feeds for farmed tambaqui (Colossoma macropomum). A total of 40 samples of freshwater from fish farms and 16 samples of feed were collected and analyzed for microbiology. A total of five species of free-living fungi were identified in fish farms: Aspergillus fumigatus, Penicillium citrinum, P. implicatum, Fusarium oxysporum and Alternaria alternata. These fungi species were counted in water samples at 35.14 CFU mL-1 and 24.69 CFU mL-1 in the dry seasons. In all fish farms, there was a higher abundance of fungi species in the rainy season. During visits to the fish farmers, it was possible to verify poor feed storage conditions. Concerning mutations in blood cells, in tambaqui (C. macropomum), a total of 159 anomalies were found, and in Leptodactylus petersii, 299 anomalies were found, with higher incidences in conditions above 1.0 CFU mL-1 in log10(x+1) fungi and in the rainy season. The occurrence of mycotoxicological contamination was confirmed in 81.25% of the analyzed samples. The quantified mycotoxin was Fumonisins B1 + B2 (375 to 1418 μg kg-1). Pearson's correlation analysis showed a significant positive correlation between Fumonisins and feed samples (r = 0.83). There was also a significant positive correlation between the abundance of fungi in water and the quantification of Fumonisins (r = 0.79). Based on the results obtained, it can be concluded that free-living fungi can be used as bioindicators of water quality in fish farms. Consequently, the lack of good management practices caused microbiological contamination of the aquatic environment.

Mycotoxins Biocontrol Methods for Healthier Crops and Stored Products

Contamination of crops with phytopathogenic genera such as Fusarium, Aspergillus, Alternaria, and Penicillium usually results in mycotoxins in the stored crops or the final products (bread, beer, etc.). To reduce the damage and suppress the fungal growth, it is common to add antifungal substances during growth in the field or storage. Many of these antifungal substances are also harmful to human health and the reduction of their concentration would be of immense importance to food safety. Many eminent researchers are seeking a way to reduce the use of synthetic antifungal compounds and to implement more eco-friendly and healthier bioweapons against fungal proliferation and mycotoxin synthesis. This paper aims to address the recent advances in the effectiveness of biological antifungal compounds application against the aforementioned fungal genera and their species to enhance the protection of ecological and environmental systems involved in crop growing (water, soil, air) and to reduce fungicide contamination of food derived from these commodities.

Molecular characterization of ochratoxigenic fungi associated with poultry feedstuffs in Saudi Arabia

Fungal and mycotoxins contamination of food and poultry feeds can occur at each step along the chain from grain production, storage, and processing. A total of 200 samples comprising of mixed poultry feedstuffs (n = 100) and their ingredients (n = 100) were collected from Riyadh, Alhassa, Qassium, and Jeddah cities in Saudi Arabia. These samples were screened for contamination by fungi. Penicillium chrysogenum was the predominant species taking into its account and frequency, respectively, in both mixed poultry feedstuff and barley samples (4,561.9 and 687 fungal colony-forming units (CFU)/g) and (66% and 17%). Moisture content was an important indicator for the count of fungi and ochratoxin A. Ochratoxin analysis of plate cultures was performed by a HPLC technique. Sample of mixed poultry feedstuff which was collected from Jeddah displayed the highest level of ochratoxin (14.8 µg/kg) and moisture content (11.5%). Corn grains samples were highly contaminated by ochratoxin A (450 and 423 µg/kg) and recorded the highest moisture contents (14.1 and 14.5%). Ochratoxin A production in fungal species isolated from mixed poultry feedstuff samples were high with P. verrucosum (5.5 μg/kg) and A. niger (1.1 μg/kg). In sorghum and corn grains, the highest ochratoxins producing species were P. viridicatum (5.9 μg/kg) and A. niger (1.3 μg/kg), respectively. Sixty-three isolates of A. niger were ochratoxigenic, and all of them showed the presence of pks genes using PKS15C-MeT and PKS15KS primer pairs. The detection technique of A. niger in poultry feedstuff samples described in the present study was successfully used as a rapid and specific protocol for early detection of A. niger without cultivation on specific media.

Dynamic Ochratoxin A Production by Strains of Aspergillus niger Intended Used in Food Industry of China

Thirty strains of Aspergillus niger, including 27 intended used in the food industry of China, were studied for their ochratoxin A (OTA) production on the three natural substrates—corn, rice, and wheat bran—at different time intervals by high-performance liquid chromatography. It was found that the frequencies of OTA for the studied 27 industrial strains ranged from 14.8% (4/27) at day 28 to 25.9% (7/27) at day 7 on corn, 14.8% (4/27) at day 7 to 33.3% (9/27) at day 21 on rice, and 22.2% (6/27) at day 7, 14, and 28 to 44.4% (12/27) at day 21 on wheat bran, respectively. The average concentrations of OTA produced by the studied 27 industrial strains ranged from 5.1 μg/kg at day 28 to 8.7 μg/kg at day 21 on corn, 4.2 μg/kg at day 7 to 17.9 μg/kg at day 14 on rice, and 4.5 μg/kg at day 7 to 7.2 μg/kg at day 21 on wheat bran, respectively. Furthermore, the OTA production in the studied 27 industrial strains of A.niger was strongly associated with their function (or application), culture substrate, and time. The saccharifying enzyme producers produced higher levels of OTA, compared with the organic acid producers, the tannase producers, and the β-galactosidase producer, while concentration differences were also observed in OTA production among strains of A.niger with the same application. In a word, some strains of A.niger intended used in the Chinese food industry indeed have the capability of producing OTA, elevating the risks to food safety associated with their use.

A risk assessment study of the occurrence and distribution of aflatoxigenic Aspergillus flavus and aflatoxin B1 in dairy cattle feeds in a central northern state, Nigeria

Nigeria, being a tropical nation, characterized by favorable climatic conditions, may display high chances of feed contaminations due to aflatoxigenic Aspergillus flavus with the consequences of health risks associated with the consumption of dairy products. A cross-sectional study was conducted to examine the risks of occurrence and distribution of aflatoxigenic Aspergillus flavus (A. flavus) and aflatoxin B1 (AFB1) contamination levels based on the European Union (EU) and United States Food and Drug Administration (USFDA) set limits. Feeds (n = 144) were collected from selected conventional and traditional dairy herds; prepared and analyzed using immuno-affinity column (IAC) and high performance liquid chromatography (HPLC) respectively. Forty eight (55.8%) isolates were identified as A. flavus of the isolated Aspergilli (n = 86). Of this proportion, 12 (25.0%) were aflatoxigenic strains. An outrageous number of the tested feeds (86.8%, n = 144) were positive for AFB1 contamination. Detectable AFB1 concentrations ranged between (0.5 and 24.8) μgKg^-1 and were distributed variously according to many factors of distribution. Eighty three (66.4%, n = 125) of the AFB1 contaminated feed samples showed AFB1 concentrations between 5 and ≥20 μgKg^-1. All-inclusive policies are key to reducing the health risks posed to the consumers of dairy products.

Sterigmatocystin in foodstuffs and feed: aspects to consider

Sterigmatocystin (STC) is a possible human carcinogen (2B) according to International Agency for Research on Cancer classification and has been associated with immunotoxic and immunomodulatory activity, together with mutagenic effects. It might be found in numerous substrates, from foods and feeds to chronically damp building materials and indoor dust. Although European Food Safety Authority concluded that the exposure to STC to be of low concern for public health, reinforces the need of data concerning exposure of European citizens. Climate change can represent an increased risk of exposure to STC since it is a crucial factor for agro-ecosystem powering fungal colonisation and mycotoxin production This aspect can represent an increased risk for European countries with temperate climates and it was already reported by the scientific community.

Taxonomic Characterization and Secondary Metabolite Profiling of Aspergillus Section Aspergillus Contaminating Feeds and Feedstuffs

Xerophilic fungal species of the genus Aspergillus are economically highly relevant due to their ability to grow on low water activity substrates causing spoilage of stored goods and animal feeds. These fungi can synthesize a variety of secondary metabolites, many of which show animal toxicity, creating a health risk for food production animals and to humans as final consumers, respectively. Animal feeds used for rabbit, chinchilla and rainbow trout production in Argentina were analysed for the presence of xerophilic Aspergillus section Aspergillus species. High isolation frequencies (>60%) were detected in all the studied rabbit and chinchilla feeds, while the rainbow trout feeds showed lower fungal charge (25%). These section Aspergillus contaminations comprised predominantly five taxa. Twenty isolates were subjected to taxonomic characterization using both ascospore SEM micromorphology and two independent DNA loci sequencing. The secondary metabolite profiles of the isolates were determined qualitatively by HPLC-MS. All the isolates produced neoechinulin A, 17 isolates were positive for cladosporin and echinulin, and 18 were positive for neoechinulin B. Physcion and preechinulin were detected in a minor proportion of the isolates. This is the first report describing the detailed species composition and the secondary metabolite profiles of Aspergillus section Aspergillus contaminating animal feeds.

Occurrence and potential transfer of mycotoxins in gilthead sea bream and Atlantic salmon by use of novel alternative feed ingredients

Plant ingredients and processed animal proteins (PAP) are suitable alternative feedstuffs for fish feeds in aquaculture practice, although their use can introduce contaminants that are not previously associated with marine salmon and gilthead sea bream farming. Mycotoxins are well known natural contaminants in plant feed material, although they also could be present on PAPs after fungi growth during storage. The present study surveyed commercially available plant ingredients (19) and PAP (19) for a wide range of mycotoxins (18) according to the EU regulations. PAP showed only minor levels of ochratoxin A and fumonisin B1 and the mycotoxin carry-over from feeds to fillets of farmed Atlantic salmon and gilthead sea bream (two main species of European aquaculture) was performed with plant ingredient based diets. Deoxynivalenol was the most prevalent mycotoxin in wheat, wheat gluten and corn gluten cereals with levels ranging from 17 to 814 and μg kg(-1), followed by fumonisins in corn products (range 11.1-4901 μg kg(-1) for fumonisin B1+B2+B3). Overall mycotoxin levels in fish feeds reflected the feed ingredient composition and the level of contaminant in each feed ingredient. In all cases the studied ingredients and feeds showed levels of mycotoxins below maximum residue limits established by the Commission Recommendation 2006/576/EC. Following these guidelines no mycotoxin carry-over was found from feeds to edible fillets of salmonids and a typically marine fish, such as gilthead sea bream. As far we know, this is the first report of mycotoxin surveillance in farmed fish species.

Fungal and mycotoxin contamination of coffee beans in Benguet province, Philippines

Coffee remains an important agricultural product in Benguet province, Philippines, but is highly susceptible to fungal and mycotoxin contamination in various stages of growth and processing and in different local climates. In this study, pre- and post-harvest coffee bean samples from temperate and warm farming areas were assessed for their fungal and mycotoxin contaminants. One hundred eighty-five fungal isolates belonging to six genera were isolated representing 88.1% of mycotoxigenic fungi. The predominant species belonged to the genus Aspergillus, which are known producers of mycotoxins. Coffee beans from the post-harvest temperate group were found to have the highest percentage mycotoxigenic contamination of 98.4%, suggesting that the risk for fungal contamination is high after drying. Determination of the mycotoxins indicated 28.6% contamination. Ochratoxin A was found to be highest in dried whole cherries which contained 97.3 μg kg(-1), whilst sterigmatocystin was also highest in dried whole cherries at 193.7 μg kg(-1). These results indicate that there are risks of fungal and mycotoxin contamination of Benguet coffee at the post-harvest stage.

Natural occurrence of emerging Fusarium mycotoxins in feed and fish from aquaculture

A new analytical method for the simultaneous determination of enniatins (ENs) and beauvericin (BEA) in fish feed and fish tissues by liquid chromatography coupled to mass spectrometry with linear ion trap (LC-MS/MS-LIT) was developed. Results showed that the developed method is precise and sensitive. The presence of emerging Fusarium mycotoxins, ENs and BEA, was determined in samples of aquaculture fish and feed for farmed fish, showing that all feed samples analyzed were contaminated with mycotoxins, with 100% coexistence. In aquacultured fish samples, the highest incidence was found in edible muscle and liver. As for the exposure assessment calculated, it was found that average consumer intake was lower than tolerable daily intake (TDI) values for other Fusarium mycotoxins.

Ochratoxin A levels in spices and dried nuts consumed in Tunisia

A total of 112 samples of spices (24 caraway, 20 coriander, 25 curcuma, 20 black pepper and 23 red pepper) and 110 samples of dried nuts (44 almonds, 42 peanuts and 24 pistachio) purchased from popular markets in 24 regions of Tunisia were analyzed for ochratoxin A (OTA) by fluorescence HPLC. The average levels of contamination of OTA found in spice samples were 244, 206, 290, 274 and 203 µg/kg, respectively, for caraway, coriander, curcuma, black pepper and red pepper. Concerning dried nut samples, the average levels were 61, 60 and 89 µg/kg, respectively, for almonds, peanuts and pistachio. Contamination levels were higher than the usual norms (10.0 OTA µg/kg) established by the European Commission in 2005 . This survey is the first to be carried out on the natural occurrence of OTA in the main spices and dried nuts consumed by the Tunisian population.

Water availability and calcium propionate affect fungal population and aflatoxins production in broiler finisher feed during storage

The aim of this study was to investigate the effects of calcium propionate, water activity (aw) and incubation time on the total fungal count and aflatoxins B₁ (AFB₁), B₂ (AFB₂), G₁ (AFG₁) and G₂ (AFG₂) production in the broiler finisher feed. The feed was added with calcium propionate (5 g kg(-1)), adjusted to 0.85, 0.90 and 0.95 aw and stored for 28 days at 25°C, analysing for mould growth and aflatoxins production every 7 days. Analysis of variance indicated that all the factors (preservative, aw and storage time) alone and in combination significantly (p < 0.001) affected the total fungal count and aflatoxins production in the feed. Minimum total fungal counts (1.99 × 10(2) CFU g(-1)) were observed in calcium propionate feed at 0.85 aw on day 1 and the highest (4.36 × 10(9) CFUs g(-1)) in control sample at 0.95 aw on day 28 of storage. During the storage period, AFB₁ content in control samples increased from 11.35 to 73.44, from 11.58 to 81.81 and from 11.54 to 102.68 ng g(-1), whereas in preserved feed the content of B₁ increased from 11.47 to 37.83, from 11.54 to 49.07 and from 11.20 to 53.14 ng g(-1) at 0.85, 0.90 and 0.95 aw, respectively. Similar patterns were noted for AFB2, AFG₁ and AFG₂ contents. All the aflatoxins readily increased over storage time; however, the increase was much slower in preserved feed that contained a lower amount of available water. This study reveals that calcium propionate addition to poultry litter along with water activity amelioration is an effective tool for controlling mould incidence and aflatoxin production in poultry feed.

Aptamer-affinity column clean-up coupled with ultra high performance liquid chromatography and fluorescence detection for the rapid determination of ochratoxin A in ginger powder

Aptamers are single-stranded oligonucleotides with high affinity and specificity and are widely used in targets separation and enrichment. Here, an aptamer-affinity column (AAC) was firstly prepared in-house through a covalent immobilization strategy. Then, ochratoxin A (OTA) in ginger powder was absorbed and enriched using the new aptamer-based clean-up technology for the first time, and was further analyzed by ultra high performance liquid chromatography with fluorescence detection. After optimization, the average recoveries for blank samples spiked with OTA at 5, 15, and 45 μg/kg ranged from 85.36 to 96.83%. Furthermore, the AAC exhibited a similar accuracy as an immunoaffinity column to clean up OTA in ginger powder. Above all, it exhibited better reusability, twice that of the immunoaffinity column, had lower toxicity and cost, and took less time. Of 25 contaminated ginger powder samples, OTA contamination levels ranged from 1.51 to 4.31 μg/kg, which were lower than the European Union (EU) regulatory limits. All the positive samples were further confirmed by ultra-fast LC with MS/MS. In conclusion, the method of clean-up based on the AAC coupled to ultra-HPLC with fluorescence detection was rapid, specific, and sensitive for the quantitative analysis of OTA in a complex matrix.

Identification of ochratoxin A producing fungi associated with fresh and dry liquorice

The presence of fungi on liquorice could contaminate the crop and result in elevated levels of mycotoxin. In this study, the mycobiota associated with fresh and dry liquorice was investigated in 3 producing regions of China. Potential toxigenic fungi were tested for ochratoxin A (OTA) and aflatoxin B1 (AFB1) production using liquid chromatography/mass spectrometry/mass spectrometry. Based on a polyphasic approach using morphological characters, β-tubulin and RNA polymerase II second largest subunit gene phylogeny, a total of 9 genera consisting of 22 fungal species were identified, including two new Penicillium species (Penicillium glycyrrhizacola sp. nov. and Penicillium xingjiangense sp. nov.). The similarity of fungal communities associated with fresh and dry liquorice was low. Nineteen species belonging to 8 genera were detected from fresh liquorice with populations affiliated with P. glycyrrhizacola, P. chrysogenum and Aspergillus insuetus comprising the majority (78.74%, 33.33% and 47.06% of total) of the community from Gansu, Ningxia and Xinjiang samples, respectively. In contrast, ten species belonging to 4 genera were detected from dry liquorice with populations affiliated with P. chrysogenum, P. crustosum and Aspergillus terreus comprising the majority (64.00%, 52.38% and 90.91% of total) of the community from Gansu, Ningxia and Xinjiang samples, respectively. Subsequent LC/MS/MS analysis indicated that 5 fungal species were able to synthesize OTA in vitro including P. chrysogenum, P. glycyrrhizacola, P. polonicum, Aspergillus ochraceus and A. westerdijkiae, the OTA concentration varied from 12.99 to 39.03 µg/kg. AFB1 was absent in all tested strains. These results demonstrate the presence of OTA producing fungi on fresh liquorice and suggest that these fungi could survive on dry liquorice after traditional sun drying. Penicillium chrysogenum derived from surrounding environments is likely to be a stable contributor to high OTA level in liquorice. The harvesting and processing procedure needs to be monitored in order to keep liquorice free of toxigenic fungi.

Natural co-occurrence of fungi and mycotoxins in poultry feeds from Entre Ríos, Argentina

A total of 120 pelleted poultry feed samples from Entre Ríos Province, Argentina, were evaluated. The aims were to investigate (1) the presence of relevant toxigenic fungi, as well as to determine the ability to produce aflatoxins (AFs) by Aspergillus section Flavi isolated strains; and (2) the natural co-occurrence of AFs, fumonisins (FBs), gliotoxin, diacetoxyscirpenol (DAS), HT-2 and T-2 toxin by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Total fungal counts were below the established value (1 × 10⁴ CFU g⁻¹). Aspergillus flavus and A. parasiticus were the only aflatoxigenic species isolated. Co-occurrence of fumonisin B₁ (FB₁), HT-2 and T-2 toxin was detected in 100% of the feeds, with mean levels from 4502 to 5813; 6.7 to 21.6 and 19.6 to 30.3 µg kg⁻¹, respectively. A large number of starter samples were co-contaminated with aflatoxin B₁ (AFB₁), FB₁, HT-2 and T-2 toxins. Gliotoxin and DAS were not found in this survey.

Survey of Aspergillus and Fusarium species and their mycotoxins in raw materials and poultry feeds from Córdoba, Argentina

The aims of the present work were: (1) to determine both mycobiota in raw materials and finisher poultry feed, as well as the ability to produce aflatoxin B1 by A. flavus strains, and (2) to evaluate the natural co-occurrence of aflatoxins (AFs), fumonisins (FBs), gliotoxin, diacetoxyscirpenol (DAS), HT-2 toxin, and T-2 toxin in poultry feed by LC-MS/MS. Nineteen percent of raw materials and 79% of finisher poultry feed samples exceeded the maximum allowed total fungal count (1 × 10(4) CFU g(-1)) to ensure hygienic quality. Aspergillus flavus was the only species belonging to section Flavi which was isolated while Fusarium verticilliodes was the prevalent species. Forty-seven percent of A. flavus strains were aflatoxin B1 producers and the highest frequency of aflatoxigenic strains was isolated from finisher poultry feeds. Principal component analysis showed that corn grains are closely related with total fungal and Fusarium counts. This positive relationship suggests that total fungal and Fusarium spp. counts in poultry feed might come mainly from corn grains. Regarding poultry feeds, in ground finisher type, Aspergillus spp. counts increased as water activity (aw) diminished. A positive relationship among aw, total fungal and Fusarium spp. counts was observed in both ground finisher and ground starter feed. Several mycotoxins were monitored in feeds by applying the LC MS/MS technique. One hundred percent of poultry samples were contaminated with FB1, and the highest levels were detected in pelleted finisher poultry. AFB1, gliotoxin, DAS, HT-2 toxin, and T-2 toxin were not detected in any poultry feed. The scarcity of available mycotoxicological studies from Argentinean poultry feed using a multitoxin analysis technique enhances the contribution of the findings of this report.

Polyaniline Langmuir-Blodgett film based aptasensor for ochratoxin A detection

Ochratoxin A (OTA) produced by Aspergillus Ochraceus and Penicillium verrucosum is a very dangerous toxin due to its toxic effects in human beings and its presence in a wide range of food products and cereals. A Langmuir-Blodgett (polyaniline (PANI)-stearic acid (SA)) film based highly sensitive and robust impedimetric aptasensor has been developed for ochratoxin A (OTA) detection. DNA Aptamer (Apt-DNA) specific to OTA has been covalently immobilized onto mixed Langmuir-Blodgett (LB) monolayer comprising of PANI-SA deposited onto indium tin-oxide (ITO) coated glass plates. This Apt-DNA/PANI-SA/ITO aptaelectrode has been characterized using scanning electron microscopy, Fourier transform-infrared spectroscopy, contact angle measurements, cyclic voltammetry and electrochemical impedance spectroscopy, respectively. The Apt-DNA/PANI-SA/ITO aptasensor shows detection of OTA by electrochemical impedance spectroscopy in the linear range of 0.0001 μg/ml (0.1 ng/ml) to 0.01 μg/ml (10 ng/ml) and 1 μg/ml-25 μg/ml with detection limit of 0.1 ng/ml in 15 min. The Apt-DNA/PANI-SA/ITO aptasensor can be reused ∼13 times. The binding or affinity constant (K(a)) of aptamer with OTA, calculated using Langmuir adsorption isotherm, is found be 1.21×10(7) M(-1).

Aflatoxigenic fungi and aflatoxin B1 in commercial pet food in Brazil

The aims of this study were to determine the aflatoxigenic mycoflora and the incidence of aflatoxin B1 in commercial samples of ready dog food. This in turn demonstrated the ability of the Aspergillus flavus and Aspergillus parasiticus strains to produce aflatoxin B1. 180 samples (standard, premium and super premium) were collected. Aspergillus was the prevalent genera followed by Penicillium and Fusarium. A. flavus and A. parasiticus were the prevalent species. All A. flavus and A. parasiticus strains from super premium samples were able to produce aflatoxin B1, whereas toxigenic strains isolated from standard and premium samples varied from 80 to 100%. A high percentage of ready pet food contaminated by toxigenic species from section Flavi was found and aflatoxin B1 levels were detected. The fungal counts from the three kinds of feed did not exceed the proposed value (1×104 cfu/g) and none of the samples exceeded the aflatoxin B1 recommended level (20 ng/g). The presence of A. flavus and A. parasiticus with aflatoxigenic ability could be a potential risk for production of AFB1 in feedstuffs when environmental storage conditions are not adequate.

The mycobiota and toxicity of equine feeds

Feed contamination can lead to nutrient losses and detrimental effects on animal health and production. The purposes of this study were to investigate the mycobiota in equine mixed feeds and to determine natural contamination with aflatoxin B1 (AFB1) and fumonisin B1 (FB1). Fungal enumeration of equine feed samples was done. A commercially available enzyme-linked immunosorbent assay kit was applied to quantify AFB1 and FB1. A comparison between ELISA and HPLC was carried out. Feed mould counts ranged from <1 x 10(2) to 1 x 10(5) cfu/g. The most frequent genus isolated was Aspergillus (40.54%), followed by Penicillium (18.38%) and Fusarium (16.22%). The most prevalent Aspergillus sp. was A. flavus (36%). AFB1 values ranged between 0.01 and 99.4 microg/kg. FB(1) levels ranged between 0.01 and 7.49 microg/kg. HPLC and ELISA methods showed positive correlation for AFB1 and FB1 determinations (r = 0.9851 and r = 0.9791, respectively). The ELISA analytical method was efficient for AFB1 and FB1 detection. The scarcity of studies on natural fungal contamination and on the presence of AFB1 and FB1 in materials used as equine feed ingredients highlights the value and contribution of this study.

Potential Aflatoxin and Ochratoxin A Production by Aspergillus Species in Poultry Feed Processing

Poultry feeds are prone to fungal growth and mycotoxin production during processing. The identification of biota with the ability to produce mycotoxins is essential. The aims of this study were (1) to monitor the mycobiota counts at different stages of poultry feed processing; (2) to determine the occurrence of Aspergillus species; (3) to evaluate the natural incidence of aflatoxins and ochratoxin A. The ability of Aspergillus spp. and its teleomorphs isolated here to produce these toxins was also investigated. Samples (144) were collected at random from a factory in Brazil. The occurrence of Aspergillus and Eurotium species was demonstrated on DRBC and DG18 media and the production of aflatoxins and ochratoxin A and their natural incidence were determined by TLC and HPLC methods. A. flavus and E. chevalieri were the most prevalent species isolated. Fungal contamination was not found after the pelleting process, though Aspergillus and Eurotium species were recovered from trough samples. High levels of aflatoxin and ochratoxin A producers were found at all stages of poultry feed processing. Also, high natural contamination with aflatoxins and ochratoxin A was found in the samples. Contact of feed with remainder poultry feed could lead to fungal contamination, so the risk of aflatoxin and/or ochratoxin A contamination of feed must be taken into account.

Mycobiota in poultry feeds and natural occurrence of aflatoxins, fumonisins and zearalenone in the Rio de Janeiro State, Brazil

The intake of mycotoxin-contaminated feeds can lead to nutrient losses and may have adverse effects on animal health and on productivity. The aims of this study were (1) to determine the mycobiota present in poultry feed samples, and (2) to evaluate the natural occurrence of aflatoxin B(1), fumonisin B(1) and zearalenone. Fungal counts were similar between all culture media tested (10(3 )CFU g(-1)). The most frequent genus isolated was Penicillium spp. (41.26%) followed by Aspergillus spp. (33.33%) and Fusarium spp. (20.63%). High precision liquid chromatography was applied to quantify aflatoxin B(1) and fumonisin B(1). Thin layer chromatography was used to determine zearalenone levels. Aflatoxin B(1 )values ranged between 1.2 and 17.5 microg kg(-1). Fumonisin B(1) levels ranged between 1.5 and 5.5 microg g(-1). Zearalenone levels ranged between 0.1 and 7 microg g(-1). The present study shows the simultaneous occurrence of two carcinogenic mycotoxins, aflatoxin B(1) and fumonisin B(1), together with another Fusarium mycotoxin (zearalenone) in feed intended for poultry consumption. Many samples contained AFB(1 )levels near the permissible maximum and it could affect young animals. A synergistic toxic response is possible in animals under simultaneous exposure.

Ochratoxin A in red paprika: relationship with the origin of the raw material

The occurrence of ochratoxin A (OA) in paprika elaborated from peppers grown in several countries (Peru, Brazil, Zimbabwe and Spain) was studied, using an immunoaffinity clean-up column coupled to liquid chromatography and fluorescence detection. The preparation of the methyl ester (OA-Me) and liquid chromatography-electrospray-ion trap-mass spectrometry was used both to confirm the identity of the chromatographic peak that correspond to OA and to quantify it at low levels or in dirty fractions. A total of 115 strains of moulds were isolated; 85 of the fungal strains were obtained from OA contaminated paprika samples and identified as belonging to the Aspergillus Section Circumdati group (A. ochraceus) and Section Nigri group (A. niger, A. carbonarius). Among the latter ones, 31% of the A. ochraceus isolates and one A. niger were OA producers in vitro. None of the mould strains isolated from paprika samples with undetectable levels of OA or concentrations below 1 microg kg(-1) were toxin producers. Great differences in OA content in paprika samples were found, and a relationship with the climatic conditions of the geographic origin of the samples, and with cultural and technical practices in pepper manipulation is suggested.

Reliable indirect competitive ELISA used for a survey of ochratoxin A in green coffee from the North of Paraná State, Brazil

The performance of an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) based on a monoclonal antibody (mAb) for ochratoxin A (OTA) detection was evaluated in a comparative study with high-performance liquid chromatography (HPLC) analysis using 68 freshly harvested coffee samples from the North of Paraná State, Brazil. The anti-OTA mAb showed high specificity and low cross-reactivity with OTA analogues (OTB and OTalpha), but cross-reacted with OTC. This ic-ELISA showed a detection limit of 3.75 ngg-1 sample, when compared to 0.80 ngg-1 by HPLC, with an ic-ELISA/HPLC correlation coefficient of 0.90. As regards OTA analysis of these coffee samples, natural contamination was detected in 10 samples (14.7%) by both methods, where the ic-ELISA values (range 3.9-7.3 ngg-1) were 1.1 to 1.6-fold higher than HPLC data (2.7-4.7 ngg-1). Five samples (7.4%) were OTA positive (range 0.84-1.30 ngg-1) only by HPLC assay, probably due to the higher detection limit reached by ic-ELISA. OTA was undetectable in 53 samples (77.9%) by both methods, while all positive samples (range 0.84-7.30 ngg-1) showed OTA levels lower than 8 ngg-1 (maximum limit recommended by the European Union). The matrix interference of green coffee was minimized by dilution of sample extracts before carrying out the ELISA assay. This mAb-based ic-ELISA can be effectively applied for OTA screening in coffee, because it is simple, sensitive and sample preparation is easy.

Occurrence of mycotoxins (ochratoxin A, deoxynivalenol) and toxigenic fungi in Moroccan wheat grains: impact of ecological factors on the growth and ochratoxin A production

The aim of the present work was to evaluate the contamination of some samples, taken from Moroccan wheat grains, by ochratoxin A (OTA), deoxynivalenol (DON) and the associated toxigenic fungi. Moreover, we focused on the influence of environmental factors on both the growth and OTA production by three strains of Aspergillus. The results showed that only few samples were contaminated by the two mycotoxins (2 samples for OTA and 7 for DON). The main isolated fungi belong to the Aspergillus, Penicillium and Fusarium genus; 74 Aspergillus and 28 Penicillium isolates were tested for their ability to produce OTA. Only 2 A. alliaceus and 14 A. niger were able to synthesize OTA. However, none of Penicillium isolates can produce this toxin under the conditions mentioned. In respect of the effects of the temperature and water activity (aw), the optimal conditions for the growth and OTA production were different. While the optimal conditions of growth for A. alliaceus and A. terreus are 30 degrees C and 0.98 aw, A. niger preferred 0.93-0.95 aw at 25 degrees C, whereas the optimal production of OTA was observed at 30 degrees C for both A. alliaceus and A. niger at 0.93 and 0.99 aw, respectively.

Influence of water activity, temperature and time on mycotoxins production on barley rootlets

AIMS

The objective of this study was to determine the ochratoxin (OT) and aflatoxin (AF) production by three strains of Aspergillus spp. under different water activities, temperature and incubation time on barley rootlets (BR).

METHODS AND RESULTS

Aspergillus ochraceus and Aspergillus flavus were able to produce mycotoxins on BR. Aspergillus ochraceus produced ochratoxin A (OTA) at 0.80 water activity (a(w)), at 25 and 30 degrees C as optimal environmental conditions. The OTA production varies at different incubation days depending on a(w). Aflatoxin B(1) (AFB1) accumulation was obtained at 25 degrees C, at 0.80 and 0.95 a(w), after 14 and 21 incubation days respectively. Temperature was a critical factor influencing OTA and AFB(1) production.

CONCLUSIONS

This study demonstrates that BR support OTA and AFB(1) production at relatively low water activity (0.80 a(w)) and high temperatures (25-30 degrees C).

SIGNIFICANCE AND IMPACT OF THE STUDY

The study of ecophysiological parameters and their interactions would determine the prevailing environmental factors, which enhance the mycotoxin production on BR used as animal feed.

Toxicokinetics and toxicodynamics of ochratoxin A, an update

Ochratoxin A (OTA) is a mycotoxin produced by fungi of two genera: Penicillium and Aspergillus. OTA has been shown to be nephrotoxic, hepatotoxic, teratogenic and immunotoxic to several species of animals and to cause kidney and liver tumours in mice and rats. Because of differences in the physiology of animal species, wide variations are seen in the toxicokinetic patterns of absorption, distribution and elimination of the toxin. Biotransformation of OTA has not been entirely elucidated. At present, data regarding OTA metabolism are controversial. Several metabolites have been characterized in vitro and/or in vivo, whereas other metabolites remain to be characterized. Several major mechanisms have been shown as involved in the toxicity of OTA: inhibition of protein synthesis, promotion of membrane peroxidation, disruption of calcium homeostasis, inhibition of mitochondrial respiration and DNA damage. The contribution of metabolites in OTA genotoxicity and carcinogenicity is still unclear. The genotoxic status of OTA is still controversial because contradictory results were obtained in various microbial and mammalian tests, notably regarding the formation of DNA adducts. More recent studies are focused on the OTA ability to disturb cellular signalling and regulation, to modulate physiological signals and thereby to influence cells viability and proliferation. The present paper offers an update on these different issues. In addition since humans and animals are likely to be simultaneously exposed to several mycotoxins, especially through their diet, the little information available on the combined effects of OTA and other mycotoxins has also been reviewed.

Mycoflora of poultry feeds and ochratoxin-producing ability of isolated Aspergillus and Penicillium species

In Brazil, commercial feedstuffs are an important component in modern animal husbandry, but there is no information available about fungal contamination and ochratoxin A (OTA) production. The aims of this study were to determine the mycoflora incidence in poultry feeds and evaluate OTA production. In addition, the ability to produce OTA by several Aspergillus and Penicillium species was investigated. A total of 96 samples of poultry feeds were collected from four factories in Rio de Janeiro. Samples were examined for total moulds, for Aspergillus and Penicillium spp. occurrence and for their relative densities on dichloran rose bengal chloramphenicol and dichloran 18% glycerol media. The capacity to produce ochratoxin A by selected Aspergillus and Penicillium species was determined by HPLC. Total mould counts were generally higher than 1 x 10(5 )CFU ml(-1). Aspergillus and Penicillium species were isolated in the highest numbers. Aspergillus flovus and Penicillium citrinum were the most prevalent species. There was a high percentage of potential OTA producers (46%). The amount of OTA produced on this substrate was enough to cause adverse effects in animals. Several strains isolated from poultry feeds were able to produce high levels of OTA on chloramphenicol yeast medium. OTA in raw materials needs to be surveyed and storage practices must be investigated to determine occurrence and establish the livestock toxicological risk in poultry feed.