Toxigenic Alternaria species from Argentinean blueberries

Blueberries are traditionally consumed in North America, some European countries and Japan. In Argentina, the blueberry crop is profitable because production starts in November, when the northern hemisphere lacks fresh fruit. Fungal contaminants can grow and produce mycotoxins in fresh fruit. The aims of this work were to identify the main genera of the mycobiota of blueberries grown in Argentina and to determine the toxicogenic potential, pathogenicity and host specificity of the species isolated. The genus Alternaria was the main component of the blueberry mycobiota (95%); minor proportions of Phoma spp. (4%) and Penicillium spp. (1%) were also isolated. According to their sporulation patterns, 127 Alternaria isolates belonged to the Alternaria tenuissima species-group, 5 to the Alternaria alternata species-group and 2 to the Alternaria arborescens species-group. The last mentioned species-group was not isolated at 5°C. Of the 134 isolates, 61% were toxicogenic in autoclaved rice; 97% of these produced alternariol (AOH) in a range from 0.14 to 119.18 mg/kg, 95% produced alternariol methylether (AME) in a range from 1.23 to 901.74 mg/kg and 65% produced tenuazonic acid (TA) in a range from 0.13 to 2778 mg/kg. Fifty two isolates co-produced the three mycotoxins. According to the size of the lesion that they caused on blueberries, the isolates were classified as slightly pathogenic, moderately pathogenic and very pathogenic. No significant differences in pathogenicity were found on different blueberry varieties. In this work, high incidence and toxicogenic potential of the Alternaria isolates from blueberries were demonstrated. Thus, more studies should be done to evaluate the health risk posed by the presence of the Alternaria toxins in blueberries and in the manufactured by-products.     

Alternaria toxins in Argentinean wheat,bran, and flour

Alternaria species have been reported to infect a wide variety of vegetables, fruits, and cereal crops. Wheat is one of the most consumed cereal worldwide. A sensitive HPLC-DAD methodology was applied to quantify alternariol (AOH), alternariol methyl ether (AME) and tenuazonic acid (TeA) in 65 samples of whole wheat, bran, and flour. The extraction methodology allowed extracting the three toxins simultaneously. Limits of detection in wheat were 3.4, 4.5, and 0.5 µg kg^?1 for AOH, AME and TeA, respectively. For bran, these data were 3.1, 4.5, and 12 µg kg^?1 and for flour 50, 70, and 14 µg kg^?1, respectively. The studied recoveries were higher than 70% and RSD was below 10%. Wheat and bran samples showed low AOH and AME contamination compared to TeA. The averages levels found for TeA in wheat, bran and flour were 19,190, 16,760, and 7360 µg kg^?1, respectively.     

Production of alternaria mycotoxins by Alternaria alternata isolated from weather-damaged wheat

The production of Alternaria mycotoxins by Alternaria alternata isolated from Chinese weathered wheat kernels were first investigated on polished rice and durum wheat grains. These mycotoxins included alternariol (AOH) and its monomethyl ether (AME), altenuene (ALT), altertoxin I (ATX-I), and tenuazonic acid (TA). Of 25 isolates tested, all were AOH and AME producers, 21 (84%) coproduced ALT and ATX-I, and 8 (32%) produced TA in rice culture. TA was the most abundant toxin produced at a level ranging from 1,369 to 3,563 mg/kg. Much smaller amounts of AOH, AME, ALT, and ATX-I were present with average concentrations of 54, 40, 44, and 8 mg/kg, respectively. There were linear correlations between the level of AOH and AME (r = 0.846), alternariols (AOH plus AME) and ALT (r = 0.785), and ATX-I and TA (r = 0.553). Polished rice medium seems to support a bit more production of Alternaria metabolites than wheat but with an insignificant difference in concentrations (P > 0.05). A study of the time-course of toxin production by A. alternata isolates indicated that AOH production began faster than any other toxins monitored, and ALT production exhibited a progressive increase throughout the experiment. TA producers might reveal their considerably higher ability to produce toxin in the field despite their low frequency.     

Mycotoxin production capability of Penicillium roqueforti in strains isolated from mould-ripened traditional Turkish civil cheese

Mould-ripened civil is a traditional cheese produced mainly in eastern Turkey. The cheese is produced with a mixture of civil and whey curd cheeses (lor). This mixture is pressed into goat skins or plastic bags and is ripened for more than three months. Naturally occurring moulds grow on the surface and inside of the cheese during ripening. In this research, 140 Penicillium roqueforti strains were isolated from 41 samples of mould-ripened civil cheese collected from Erzurum and around towns in eastern Turkey. All strains were capable of mycotoxin production and were analysed using an HPLC method. It was established that all the strains (albeit at very low levels) produced roquefortine C, penicillic acid, mycophenolic acid and patulin. The amounts of toxins were in the ranges 0.4–47.0, 0.2–43.6, 0.1–23.1 and 0.1–2.3 mg kg^?1, respectively. Patulin levels of the samples were lower than the others. The lowest level and highest total mycotoxin levels were determined as 1.2 and 70.1 mg kg^?1 respectively. The results of this preliminary study may help in the choice of secondary cultures for mould-ripened civil cheese and other mould-ripened cheeses.     

Alternaria toxins in wheat during the 2004 to 2005 Argentinean harvest

The natural occurrence of Alternaria mycotoxins in Argentinean wheat from the zone 5 South during the 2004 to 2005 harvest was investigated in 64 wheat samples. All samples were highly contaminated with a wide range of fungal species. Alternaria was found as the main component of the mycota, with an infection percentage of 100%. Three mycotoxins produced by species of Alternaria were determined in wheat: alternariol, alternariol monomethyl ether, and tenuazonic acid. Alternariol was detected in 4 (6%) of 64 samples, with a range of 645 to 1,388 microg/kg (mean of 1,054 microg/kg); alternariol monomethyl ether, with a range of 566 to 7,451 microg/kg (mean of 2,118 microg/kg) in 15 (23%) of 64 samples; and tenuazonic acid in 12 (19%) of 64 samples, with a range of 1,001 to 8,814 microg/kg (mean, 2,313 microg/kg). Alternariol monomethyl ether was the predominant toxin, but tenuazonic acid was detected in higher concentrations. Alternariol was present in fewer samples and in lower levels than were the other toxins. Tenuazonic acid and alternariol monomethyl ether occurred together in four samples, while tenuazonic acid and alternariol co-occurred in one sample. This the first report of the natural occurrence of Alternaria mycotoxins in Argentinean wheat. Toxin levels were high, probably due to the heavy infection with Alternaria species found in the samples.     

Trichothecenes and zearalenone production by Fusarium equiseti and Fusarium semitectum species isolated from Argentinean soybean

Fusarium equiseti and Fusarium semitectum represent the most abundant species in the Fusarium complex isolated from flowers, soybean pods and seeds in Argentina. The aim of the present study was to assess the production of major type A and type B trichothecenes (diacetoxyscirpenol, neosolaniol, T-2 toxin and HT-2 toxin, nivalenol, deoxynivalenol) and zearalenone by 40?F. equiseti and 22 F. semitectum isolates on rice culture. Mycotoxins were determined by HPLC with fluorescence detection after derivatisation with 1-anthronylnitrile for type A trichothecenes (i.e. diacetoxyscirpenol, neosolaniol, T-2 toxin and HT-2 toxin), by HPLC with UV detection for type B trichothecenes (i.e. nivalenol and deoxynivalenol), and by TLC for zearalenone. A total of 22 of 40?F. equiseti isolates produced diacetoxyscirpenol, nivalenol and ZEA alone or in combination, whereas only two of 20?F. semitectum isolates were nivalenol and ZEA producers. Both Fusarium species did not produce any deoxynivalenol, neosolaniol, T-2 toxin and HT-2 toxin. The variable retention in toxigenicity displayed by both fungal species suggests that these species have a saprophytic lifestyle in the soybean agroecosystem in Argentina.     

Trichothecenes and zearalenone production by Fusarium equiseti and Fusarium semitectum species isolated from Argentinean soybean

Fusarium equiseti and Fusarium semitectum represent the most abundant species in the Fusarium complex isolated from flowers, soybean pods and seeds in Argentina. The aim of the present study was to assess the production of major type A and type B trichothecenes (diacetoxyscirpenol, neosolaniol, T-2 toxin and HT-2 toxin, nivalenol, deoxynivalenol) and zearalenone by 40?F. equiseti and 22 F. semitectum isolates on rice culture. Mycotoxins were determined by HPLC with fluorescence detection after derivatisation with 1-anthronylnitrile for type A trichothecenes (i.e. diacetoxyscirpenol, neosolaniol, T-2 toxin and HT-2 toxin), by HPLC with UV detection for type B trichothecenes (i.e. nivalenol and deoxynivalenol), and by TLC for zearalenone. A total of 22 of 40?F. equiseti isolates produced diacetoxyscirpenol, nivalenol and ZEA alone or in combination, whereas only two of 20?F. semitectum isolates were nivalenol and ZEA producers. Both Fusarium species did not produce any deoxynivalenol, neosolaniol, T-2 toxin and HT-2 toxin. The variable retention in toxigenicity displayed by both fungal species suggests that these species have a saprophytic lifestyle in the soybean agroecosystem in Argentina.     

AFLP variability, toxin production, and pathogenicity of Alternaria species from Argentinean tomato fruits and puree

Large amounts of tomato fruits and derived products are produced in Argentina and may be contaminated by Alternaria toxins. Limited information is available on the genetic variability, toxigenicity, and pathogenicity of Alternaria strains occurring on tomato. We analyzed 65 Alternaria strains isolated in Argentina from tomato fruits affected by black mould and from tomato puree, using amplified fragment length polymorphisms (AFLPs) technique. AFLP analysis resolved the set of strains in 3 main clusters (DICE similarity values of 58 and 60%) corresponding to A. alternata/tenuissima (44 strains), A. arborescens (15 strains) and to an unknown group (6 strains). Most of the representative strains, belonging to each AFLP cluster, when cultured on rice, produced tenuazonic acid (up to 46,760 mg/kg), alternariol monomethyl ether (AME, up to 1860 mg/kg), and alternariol (up to 70 mg/kg). The toxin profile related to the strains was not related to any AFLP cluster, except for AME which was produced at lower level by A. arborescens. Most of strains were pathogenic on two types of commonly cultivated tomato fruits. These findings provide new information on the variability within the Alternaria species complex associated with tomato disease.     

Evaluation of exopolysaccharide production by Leuconostoc mesenteroides strains isolated from wine

ABSTRACT:  Exopolysaccharide (EPS)-producing lactic acid bacteria are responsible for the alteration of wine and other fermented beverages. The potential to produce EPS was investigated for Leuconostoc mesenteroides strains isolated from Spanish grape must and wine. Most strains were able to produce EPS from sucrose containing media. Based on their EPS-producing phenotype and on their EPS monosaccharide composition, the L. mesenteroides strains analyzed could be arranged in 2 groups. One group comprises mucoid strains producing a glucan polymer, and the other group includes strains producing a fructan polymer. The presence of a glucosyltransferase encoding gene in the glucan producing L. mesenteroides strains was assayed by PCR. Two primer sets, PF1-PF8 and GTFF-GTFR, were used to amplify internal fragment of known glucosyltransferase genes. None of the glucan-producing strains gave a positive amplicon by the primer sets used. Therefore, new tools need to be developed to broaden the range of potentially spoiling agents detected by PCR in fermented beverages.     

Temperature and water activity effects on growth and temporal deoxynivalenol production by two Argentinean strains of Fusarium graminearum on irradiated wheat grain

The ability of six strains of Pichia anomala, four strains of Pichia kluyveri and two strains of Hanseniaspora uvarum predominant during coffee processing to produce polygalacturonase (PG), pectin esterase (PE) and pectin lyase (PL) in yeast polygalacturonic acid medium (YPA) and in coffee broth (CB) was studied. For comparison, a reference strain of Kluyveromyces marxianus CCT 3172 isolated from cocoa and reported to produce high amount of PG was included.

Initial screening of PG activity using YPA medium showed that K. marxianus CCT 3172, P. anomala S16 and P. kluyveri S13Y4 had the strongest activity. Enzymatic assays showed that the four yeast species secreted PG, but none of the yeasts investigated was found to produce PE or PL. P. anomala S16 and P. kluyveri S13Y4 were found to produce higher amounts of PG when grown in CB than in YPA. When K. marxianus CCT 3172, P. anomala S16 and P. kluyveri S13Y4 were grown in YPA broth adjusted to pH of 3.0–8.0 and incubated at temperatures of 15–40 °C, the three yeast species secreted the highest amount of PG at pH 6.0 and at 30 °C. For PG secreted by K. marxianus CCT 3172 and P. anomala S16, the optimum pH and temperature for the enzymatic activity were 5.5 and 40 °C, respectively. On the other hand, PG produced by P. kluyveri S13Y4 showed the highest activity at pH 5.0 and 50 °C.

Significant differences in the extracellular activity of PG were found between the yeasts species as well as between strains within same species. High amounts of PG were produced by two strains of P. anomala and P. kluyveri. It is therefore likely that strains of those two species may be involved in the degradation of pectin during coffee fermentation.     

Toxigenic potential of Fusarium culmorum strains isolated from French wheat

Sixty F. culmorum strains were isolated from wheat grains collected from different wheat-growing areas in France and from different cultivars. The isolates were grown on autoclaved wheat grain to assess their ability to produce trichothecenes and zearalenone. Fungal biomass was evaluated through the ergosterol grain content. All the isolates produced zearalenone (0.39-1660mg kg -1 ). Thirty-five of the 60 F. culmorum produced nivalenol (0.11-11.7mg kg -1 ), 12 of 60 produced fusarenone X (0.05-8.42mg kg -1 ), five of 60 produced 15-acetyldeoxynivalenol (0.48- 27.7mg kg -1 ), 13 of 60 produced 3-acetyldeoxyni-valenol (0.07-21.0mg kg -1 ) and 24 of 60 produced deoxynivalenol (0.92-51.9mg kg -1 ). According to the results, the distribution of the different chemotypes as well as the high and the low mycotoxin-producing Fusarium strains could not be associated to geographical origin.     

失活乳酸菌去除柑橘汁中链格孢霉毒素TeA工艺优化

柑橘果实易受链格孢霉菌等病原微生物的污染产生并积累链格孢霉毒素,其中细交链孢菌酮酸(tenuazonic acid,TeA)是毒性最强的一种链格孢霉毒素,具有潜在的致癌性和细胞毒性,对消费者的健康和安全构成严重威胁。为降低柑橘汁中TeA含量,本研究利用灭活乳酸菌菌体细胞作为吸附剂,主要研究其吸附去除柑橘汁中TeA的工艺条件。首先通过单因素试验分析灭活乳酸菌菌粉添加量、吸附时间、TeA初始质量浓度和pH值对TeA去除率的影响,然后采用响应面法Box-Behnken设计对吸附去除橙汁中TeA工艺条件进行了优化,得到最佳工艺参数为灭活乳酸菌菌粉添加量1.20g/20mL、吸附时间11.43h、TeA初始质量浓度250μg/L、橙汁pH3.15,在此条件下,TeA去除率为86.98%。同时建立了TeA去除率与各影响因素间的二次多项式回归模型,并对该模型进行了验证,结果表明模型拟合程度高,预测效果好。     

Mycotoxin production in wheat grains by different Aspergilli in relation to different relative humidities and storage periods

Four different Aspergilli (Aspergillus oryzae, A. parasiticus, A. terreus and A. versicolor) were grown on wheat grains underdifferent degrees of relative humidity 14, 50, 74, 80 and 90%. Samples of wheat grains were taken monthly for a period of six months and examined for mycotoxin production. A. oryzae was found to produce aflatoxins B1, B2, zearalenone, DON and T-2 toxins under elevated degrees of humidity and prolonged periods of storage. A. parasiticus produced aflatoxins B1, G1, NIV, DON and T-2 toxins in high concentrations during a period of not more than three months storage at 14% relative humidity; at an increased level of relative humidity of 74% ochratoxin A, zearalenone and sterigmatocystin were also produced at high levels. The isolate was drastic in toxin production. A. terrus produced toxins at 14% relative humidity (aflatoxin G2 and DON) at levels much higher than any other prevalent degrees of humidity. A. versicolor is highly sensitive to relative humidity and grain moisture content It produced aflatoxins B1, G1, NIV and DON at a relative humidity of 50% and another toxins (aflatoxin G2, ochratoxins A, B and zearalenone) at 74%. The microorganism can be considered a trichothecene producer under suitable relative humidity.     

Trichothecene genotypes and chemotypes in Fusarium graminearum strains isolated from wheat in Argentina

Argentina is the fourth largest exporter of wheat in the world. The main pathogen associated with Fusarium Head Blight (FHB) of wheat in Argentina is Fusarium graminearum lineage 7 also termed F. graminearum sensu stricto in the F. graminearum species complex, which can produce the Type B trichothecenes, usually deoxynivalenol (DON) and its acetylated forms (3-ADON and 15-ADON) or nivalenol (NIV). We used a multiplex PCR assay of Tri3, Tri7, and Tri13 to determine the trichothecene genotype of 116 strains F. graminearum collected from three locations in Argentina and then verified the chemotype by chemical analysis. PCR assays and chemical analyses gave the same results for all strains that produced trichothecenes. Most strains (> 92%) had the 15-ADON genotype, with the remaining strains having the DON/NIV genotype. We observed neither the NIV nor the 3-ADON genotypes amongst the strains evaluated. The nine strains with the DON/NIV genotype produced DON when analyzed chemically. Thus, the Argentinean populations of F. graminearum are similar to those from wheat elsewhere in the world, in that all the strains produced DON/15-ADON and belong to lineage 7. However approximately 8% of the strains tested were incorrectly diagnosed as DON/NIV producers with the current multiplex PCR and were only DON producers by chemical analysis.     

Mycotoxin production in amber durum wheat stored at 15 and 19% moisture content

Ochratoxin A and citrinin developed in 11 kg parcels of amber durum wheat at 15% and 19% initial moisture content (MC) exposed to simulated bulk storage in a Manitoba granary for 60 weeks between July 1984 and September 1985. Other biotic and abiotic variables were monitored throughout the storage period. Ochratoxin A reached maximum levels of 11.8 and 0.11 ppm at 19 and 15% initial MC, respectively, during weeks 44-48; citrinin reached levels of 80.0 and 0.65 ppm at these respective moistures during the same period. The effect of 19% initial MC was significantly greater for the following variables: ochratoxin A, citrinin, Aspergillus flavus, Aspergillus glaucus group species, Alternaria species, Aspergillus versicolor, bacteria, fungal propagule count, seed germination, O2, CO2, moisture content, and fat acidity. Principal component analysis indicated that the first two components, describing greater than 60% of the variability in the data, partially defined the ecological relationships leading to mycotoxin production in the stored durum wheat system.     

Effect of water activity and temperature on growth of ochratoxigenic strains of Aspergillus carbonarius isolated from Argentinean dried vine fruits

Aspergillus carbonarius is an ochratoxin A (OTA) producing fungus, predominantly responsible for the production of this mycotoxin in grapes, wine and dried vine fruits. The objective of this study was to determine the in vitro effects of water activity (a(w), 0.80-0.95) and temperature (15-35 degrees C) on lag phase extension and radial growth rate of a cocktail inoculum of four strains of A. carbonarius. The maximum growth rate was observed at 0.95 a(w) and 30 degrees C (17.46 mm day(-1)). In general, growth rates increased with the increment of a(w). No growth was observed at a(w) below 0.85. For all a(w) levels tested the highest growth rate was detected at 30 degrees C. At 15 degrees C growth only occurred at the higher a(w) levels evaluated (0.925 and 0.95) at a growth rate of 3.82 and 5.57 mm day(-1) respectively. The shortest lag phase (0.26 days) was found at 0.925 a(w) and 35 degrees C. At marginal conditions of a(w) and temperature the lag phases increased, being the highest registered at 20 degrees C and 0.89 a(w) (33.7 days). The pattern of effects of environmental factors on growth was similar among Argentinean A. carbonarius strains and those from several European countries, Israel and Australia.     

臭氧处理对交链孢菌生长及其毒素积累的抑制作用

交链孢菌（Alternaria spp.）易侵染农作物,引起农产品病害,而且能够代谢产生交链孢毒素,包括细交链孢酮酸（tenuazonic acid,TeA）、交链孢酚（alternariol,AOH）、交链孢酚单甲醚（alternariol monomethyl ether,AME）等,严重影响人体健康。因此,亟需高效、安全的方法用以防控交链孢菌及其毒素积累。本实验研究了臭氧处理对体外互隔交链孢（A. alternata）生长及其产毒能力的影响。结果表明,臭氧处理组的菌落直径显著低于对照组（P＜0.05）,且臭氧处理可显著抑制互隔交链孢产生TeA、AOH、AME这3 种交链孢毒素;利用扫描电子显微镜观察臭氧处理后互隔交链孢的微观形态,发现孢子和菌丝发生了凹陷、褶皱、断裂等异常现象;臭氧处理后的交链孢菌对番茄果实的致病力明显减弱,同时交链孢菌的产毒能力明显降低,20 mg/L臭氧处理条件下TeA、AOH、AME含量比对照组分别减少了36.1%、89.9%、93.2%。此外,臭氧对TeA、AOH、AME具有降解作用,降解率随着臭氧质量浓度的增加和处理时间的延长而显著提高,TeA经过20 mg/L臭氧处理30 min即可被完全降解,AOH及AME经20 mg/L臭氧处理120 min后降解率可达90%以上。综上,臭氧处理可以作为农产品及其制品中互隔交链孢及其毒素污染的防治手段。     

Mycotoxin production by isolates of Fusarium lactis from greenhouse sweet pepper (Capsicum annuum)

Internal fruit rot, caused by Fusarium lactis, is an important disease of sweet pepper (Capsicum annuum) in Canadian greenhouses. Production of the mycotoxins fumonisin B₁ (FB₁), moniliformin (MON) and beauvericin (BEA) by F. lactis (17 isolates) and the related species F. proliferatum (three isolates) and F. verticillioides (one isolate), which are also associated with internal fruit rot, was evaluated on rice medium. All 21 isolates examined were found to produce BEA, at concentrations ranging from 13.28 to 1674.60 ppm, while 13 of 17 F. lactis isolates and two of three F. proliferatum isolates produced MON (0.23 to 181.85 ppm). Only one isolate of F. lactis produced detectable levels of FB₁ in culture, whereas all three F. proliferatum isolates and the F. verticilloides isolate produced this mycotoxin (0.28 to 314 ppm). Production of FB₁, MON and BEA was also evaluated in inoculated pepper fruits showing mild or severe symptoms of infection. FB₁ could be detected in both lightly and heavily diseased fruit tissue after inoculation with F. lactis, F. proliferatum or F. verticilloides, at concentrations ranging from 0.61 to 8.04 ppm. BEA was also detected in lightly and heavily diseased fruit tissue inoculated with F. lactis, as well as in heavily diseased tissue inoculated with F. proliferatum (3.00 to 19.43 ppm), but not in tissue inoculated with F. verticilloides. MON was detected in all tissues inoculated with F. proliferatum or F. verticilloides, and in heavily diseased tissue inoculated with F. lactis (0.03 to 0.27 ppm). The three mycotoxins were also found in naturally infected sweet pepper fruits exhibiting symptoms of internal fruit rot and collected from a commercial greenhouse. The production of MON, BEA and FB₁ alone or in combination by isolates of F. lactis suggests that development of internal fruit rot of sweet pepper is an important food safety concern, and that every effort should be made to cull infected fruit before it makes it to market.     

丙酮丁醇梭菌发酵小麦麸皮生产丁醇

对丙酮丁醇梭菌(Clostridium acetobutylicum)8016发酵小麦麸皮或麸皮混合其他非粮淀粉质原料生产丁醇进行了研究。实验结果表明,当初始糖浓度为55g/L时,以纯麸皮为底物,发酵终点总溶剂达到21.43g/L,丁醇13.08g/L,糖醇转化率39.57%;以麸皮混合红薯、木薯为底物,发酵终点总溶剂达到22.37g/L,丁醇13.24g/L,糖醇转化率为39.95%,均能达到传统玉米醪发酵丁醇水平。证明小麦麸皮作为一种粮食加工废弃物完全可以替代粮食用于丙酮丁醇发酵。     

Zearalenone production by Fusarium species isolated from soybeans

The incidence of species of Fusarium in soybeans and their ability to produce zearalenone was evaluated. Fusarium species were present in 5% of the beans examined. Of 43 isolates 41.8% were toxinogenic, belonging to the following species (number of zearalenone producers/number of isolates tested): F. equiseti (5/11), F. semitectum (13/24), F. moniliforme (0/6) and Fusarium spp. (0/2). Two high zearalenone producing isolates of F. equiseti and F. semitectum produced on rice 2.050 and 1.370 μg of zearalenone per g of substrate, respectively. When these strains were inoculated on soybeans detectable amounts of zearalenone were not produced although the fungi grew vigorously. This suggests that soybeans are not a good substrate for the biosynthesis of zearalenone by Fusarium species.