Pre-harvest accumulation of deoxynivalenol in sweet corn ears inoculated with Fusarium graminearum

Three types of commercial sweet corn hybrids [sugary (su1), shrunken or 'supersweet' (sh2) and sugary enhancer (se1)] were silk channel inoculated in 1996 and 1997 with a macroconidial suspension of Fusarium graminearum to determine how early the mycotoxin deoxynivalenol accumulates in kernels. Disease symptoms rapidly developed on all hybrids and were apparent 4 days after inoculation. Symptoms stabilized by 28 days after inoculation. Toxin levels were greater than 1 μg/g in kernels as early as 2 weeks after silk emergence and rapidly increased to extremely high levels. Susceptibility in all hybrids decreased as the silk dried out. Deoxynivalenol concentrations were correlated to disease severity. There was some indication that the sh2 genotype was more susceptible than the su1 or se1 genotypes. These results suggest that improvement needs to be made in sweet corn with respect to resistance to gibberella ear rot.     

Evaluation of mycotoxin-contaminated cereals for their use in animal feeds in Hungary

In the period between December 5, 1991 and September 17, 1998, 760 maize, 367 wheat, 119 soybean, 222 barley, 85 bran, 32 triticale, 60 oat, 14 rye and 22 sunflower samples were investigated for the presence and concentration of seven fusariotoxins (T-2 toxin, zearalenone, deoxynivalenol, nivalenol, diacetoxyscirpenol, HT-2 toxin, fusarenone-X) and OTA. The comparison of analytical data with those of the relevant literature revealed that although the incidence rate and/ or concentration of Fusarium mycotoxins and OTA in Hungarian-grown cereals is occasionally considerable, the position of the country is not worse than the average of countries. Our findings indicate that soybean tends to be good substrate for trichothecene-producing fungi and the rate of contamination is regarded as substantial. The commodities were assorted into one of three quality categories. The proportion of objectionable samples was only 3.0, 2.2, 2.3 and 1.7% in maize, wheat, barley and soybean samples, respectively. However, this low rate of objection might still be a source of great economic loss. The proportion of objectionable samples was much higher in the case of bran, oat and triticale (7.1, 6.7, and 6.3%, respectively). The results of the present investigation indicate a need for regular screening for mycotoxins of importance and individual appraisal of each commodity from the point of their use in animal feeds.     

Fate of the fusarium mycotoxins, deoxynivalenol, nivalenol and zearalenone, during extrusion of wholemeal wheat grain

In the European Union, deoxynivalenol in cereals and cereal products is controlled by recent legislation with the objective of minimizing consumer exposure to this mycotoxin. Relatively few studies have examined the loss of Fusarium mycotoxins during processing and whether this is accurately reflected by the processing factors. The behaviour of deoxynivalenol, nivalenol and zearalenone during extrusion of naturally contaminated wholemeal wheat flour has been examined using pilot-scale equipment. Factors examined were temperature and moisture content. Concentrations of the three mycotoxins were little changed by extrusion although the amount of deoxynivalenol decreased at the lowest moisture content. However, this effect did not appear to be temperature-dependent, suggesting that the apparent loss is either due to binding or inability to extract the residue. Under some conditions, concentrations of the mycotoxins, particularly nivalenol, were higher after extrusion.     

丁香酚、香芹酚和百里香酚对禾谷镰刀菌的抑菌活性及机制

以转录组技术为基础,研究丁香酚、香芹酚和百里香酚对禾谷镰刀菌的抑制作用及作用机理。方法：借助体外抑菌实验测定丁香酚、香芹酚和百里香酚对禾谷镰刀菌菌丝生长、孢子萌发和呕吐毒素生物合成的有效作用浓度;通过测定丁香酚、香芹酚和百里香酚处理后菌丝液的电导率、ATP含量和丙二醛含量进一步从细胞水平探讨其作用位点;通过转录组学阐明丁香酚、香芹酚和百里香酚抑制禾谷镰刀菌生长和毒素合成的分子机制。结果：3 种植物精油活性成分中,百里香酚的抗真菌活性最强。丁香酚、香芹酚和百里香酚可破坏禾谷镰刀菌细胞膜完整性,引起电解质渗漏,能量代谢失衡。此外,3 种植物精油活性成分通过核糖体、线粒体结构和转录组水平上的酶合成发挥对禾谷镰刀菌的抑制作用。     

镰孢菌毒素的主要类型及其收获前后的生物防控方法

镰孢菌毒素是镰孢菌属真菌产生的多种有毒性的次级代谢产物的总称,在自然界中分布极为广泛,是常见的污染粮食和饲料的真菌毒素种类,严重威胁人畜健康.近年来镰孢菌毒素污染粮食和饲料的问题日益严重,已成为普遍关注的食品安全和饲料安全热点问题之一.由于农产品收获后的物理、化学脱毒方法存在着脱毒不彻底、营养成分流失以及化学试剂残留对...     

Growth inhibition of Fusarium graminearum and deoxynivalenol detoxification by lactic acid bacteria and their application in sourdough bread

Eight lactic acid bacteria (LAB) strains were screened for their ability to inhibit Fusarium graminearum (F. graminearum) growth and remove deoxynivalenol (DON). Furthermore, the selected LAB strains were applied as starter cultures to evaluate their performance during the breadmaking process. Lactobacillus plantarum (L. plantarum) AR524 exhibited strong inhibitory activity against F. graminearum growth in a pH-dependent manner and removed up to 40.9% of DON, mainly through cell wall binding. Compared with the control, L. plantarum AR524 inhibited 60.19% of F. graminearum growth and removed 50.53% of DON during breadmaking. The texture properties of the bread were also remarkably improved by L. plantarum AR524, and its shelf life was extended from 3 days to 6 days without the application of any chemical preservatives. Therefore, L. plantarum AR524 shows excellent potential for application as a bioprotective starter culture in bakery products.     

Survey of fumonisins B1, B2 and B3 in conventional and organic retail corn products in Spain and Italy and estimated dietary exposure

A survey was conducted to determine the occurrence of fumonisin B₁, B₂ and B₃ during 2007 in 186 samples of organic and conventional locally available corn products. Samples included baby food (n = 62), corn flour (11), cornflakes (23), pasta (14), cookies (17) and other corn products (59) were obtained from popular markets of Valencia (Spain) and Perugia (Italy). The analytical method used pressurized liquid extraction and liquid chromatography/electrospray ionization tandem mass spectrometry with a triple quadrupole (QqQ) analyser. Of the 104 Spanish samples, 22% contained levels in the range of 2–449 µg kg^?1, 2–229 µg kg^?1 and 6–105 µg kg^?1 for FB₁, FB₂ and FB₃, respectively, while 19 (23%) of the 82 Italian samples were positive with quantifiable levels between 2–235 µg kg^?1, 3–187 µg kg^?1, and 4–40 µg kg^?1 for fumonisins B₁, B₂ and B₃, respectively. Overall, none of the Italian samples and only one organic baby food sample from a Spanish market was above the maximum permitted levels established by European legislation. Fumonisins were found mostly in corn flour followed by cookies and cornflakes. Eleven samples from Spain and nine samples from Italy were organic products, being contaminated the 72% and 77% of the samples, respectively. Analysis of the results showed that levels of fumonisins in corn products were similar in Italy and Spain. The safety of fumonisin intake through corn products was demonstrated by the calculation of the estimated daily intake of both populations considering organic and conventional products separately, which ranged from 1.7 × 10^?3 to 0.72 µg kg^?1 bw day^?1 and comparing them with the provisional maximum total daily intake (PMTDI) of 2 µg kg^?1 bw day^?1 established by the European Union.     

Toxicological studies on Thermomyces lanuginosus xylanase expressed by Fusarium venenatum, intended for use in food

The xylanase used in this study was produced by a submerged fermentation of Fusarium venenatum and contained a gene code originating from Thermomyces lanuginosus. The enzyme was subject to a 13-week toxicological test in rats and in vitro tests to document its safety in use. The enzyme is to be applied as a processing aid in the baking industry to improve handling and stability of dough. The enzyme was not found to be mutagenic in the Salmonella typhimurium reverse mutation assay, nor did it cause chromosomal aberrations in cultured human lymphocytes. Oral administration to rats of up to 10.0ml/kgbw/day (equivalent to a Total Organic Solids dosage of 1.12g/kgbw/ day or a xylanase dosage of 89422FXU(W)/kgbw/day) for 13 weeks did not cause any adverse effect.