Correlation of rainfall and levels of deoxynivalenol in wheat from Uruguay, 1997-2003

Deoxynivalenol: An Overview on Occurrence, Chemistry, Biosynthesis, Health Effects and Its Detection, Management, and Control Strategies in Food and Feed

Mycotoxins are fungi-produced secondary metabolites that can contaminate many foods eaten by humans and animals. Deoxynivalenol (DON), which is formed by Fusarium, is one of the most common occurring predominantly in cereal grains and thus poses a significant health risk. When DON is ingested, it can cause both acute and chronic toxicity. Acute signs include abdominal pain, anorexia, diarrhea, increased salivation, vomiting, and malaise. The most common effects of chronic DON exposure include changes in dietary efficacy, weight loss, and anorexia. This review provides a succinct overview of various sources, biosynthetic mechanisms, and genes governing DON production, along with its consequences on human and animal health. It also covers the effect of environmental factors on its production with potential detection, management, and control strategies.

Production of type-B trichothecenes by Fusarium meridionale, F. graminearum, and F. austroamericanum in wheat plants and rice medium

Food security goes beyond food being available; the food needs to be free of contaminants. Trichothecenes mycotoxins, produced by Fusarium fungus, are. among the most frequently found contaminants of wheat. In this study, we evaluated the production of trichothecenes Deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-AcDON), 15-acetyldeoxynivalenol (15-AcDON), and nivalenol (NIV) by Fusarium meridionale, F. austroamericanum, and F. graminearum grown in wheat plants and rice medium. Fusarim meridionale was efficient only in the production of NIV (production range (pr) from 1340 to 2864 µg kg^-1 in wheat plant), and F. austroamericanum in the production of 3-AcDON (pr from 50 to 192 µg kg^-1 in wheat plant, and from 986 to 7045 µg kg^-1 in rice medium) and DON (pr from 4076 to 13,701 µg kg^-1 in wheat plant, and from 184 to 43,395 µg kg^-1 in rice medium). Already, F. graminearum was efficient in the production of 3-AcDON only in rice medium (pr from 81 to 2342 µg kg^-1), 15-AcDON in wheat plant (pr from 80 to 295 µg kg^-1) and in rice medium (pr from 436 to 8597 µg kg^-1), and DON also in wheat plant (pr from 7746 to 12,046 µg kg^-1) and in rice medium (pr from 695 to 49,624 µg kg^-1). The specificity of F. meridionale in the production of NIV but not the production of DON could generate a food security problem in regions where this species occurs and the amounts of NIV in grains and derivatives are not regulated in the food chain, as in Brazil.

Dietary Intake of Mycotoxin Susceptible Foods by Brazilian Nursing Mothers

Background:

The human milk has several health benefits to the mother and child, and it is the ideal form of nutrition for infants. However, some food contaminants such as mycotoxins can be transferred from the mother to the child through breast milk.

Objective:

To access the dietary intake of mycotoxin susceptible foods by nursing mothers.

Methods:

The dietary intake of mycotoxin susceptible foods was investigated by interviewing nursing mothers (n = 86), who were registered donors of the Human Milk Bank (HMB) of Blumenau (Brazil), through a food frequency questionnaire (FFQ). The mothers were contacted and those who agreed to answer the FFQ were recruited for the study group. The interview was conducted individually, face to face with each mother, by a trained researcher. The FFQ was divided into three food Groups (vegetables, animal and beverages, respectively), considered most prone to mycotoxins contamination. Socio-demographic characteristics of the mothers were also obtained.

Results:

The FFQ revealed a high weekly intake of foods susceptible to fungi and mycotoxin contamination. Consumption of wheat, coffee and cow’s milk was reported by 52, 44 and 51% of the mothers, respectively. The consumption of those foods occurred daily to more than 7 times per week.

Conclusion:

The study revealed that Brazilian nursing mothers frequently consume foods susceptible to mycotoxin contamination, especially wheat and its by-products. Brazilian health, environmental and agriculture authorities should pay permanent attention by applying monitoring programs to grains and cereals - both imported and domestically produced - as they are highly susceptible to fungi and mycotoxin contamination, which can be transferred to infants via breastfeeding, apart from harming the general population health.

Deoxynivalenol in wheat from the Northwestern region in China

Because of global warming and changes in farming systems, Fusarium head blight has gradually spread towards high-latitude regions such as Northwestern China. A survey was conducted to assess the prevalence and concentration of deoxynivalenol (DON) in wheat harvested during 2013 from the Shaanxi, Ningxia, Gansu, and Xinjiang provinces in China. DON concentration in 181 wheat samples was analysed by high-performance liquid chromatography combined with ultraviolet detection. Of the wheat samples, 82.9% were contaminated with DON, with a mean DON concentration of 500 μg/kg. According to the Chinese standard limits for DON, 10% of the positive samples were above the maximum limit of 1000 μg/kg. Regions with higher humidity showed higher levels of DON in the wheat samples. These results show the necessity of raising awareness of DON contamination in people from Northwestern China to protect their health from the risk of exposure to DON.

Fusarium and Aspergillus mycotoxins contaminating wheat silage for dairy cattle feeding in Uruguay

Wheat is one of the most important cultivated cereals in Uruguay for human consumption; however, when harvest yields are low, wheat is usually used in ensiling for animal feeding. Ensiling is a forage preservation method that allows for storage during extended periods of time while maintaining nutritional values comparable to fresh pastures. Silage is vulnerable to contamination by spoilage molds and mycotoxins because ensilage materials are excellent substrates for fungal growth. The aim of the study was to identify the mycobiota composition and occurrence of aflatoxins and DON from wheat silage. A total of 220 samples of wheat were collected from four farms in the southwest region of Uruguay were silage practices are developed. The main fungi isolated were Fusarium (43%) and Aspergillus (36%), with Fusarium graminearum sensu lato and Aspergillus section Flavi being the most prevalent species. Aflatoxin concentrations in silo bags ranged from 6.1 to 23.3μg/kg, whereas DON levels ranged between 3000μg/kg and 12,400μg/kg. When evaluating aflatoxigenic capacity, 27.5% of Aspergillus section Flavi strains produced AFB1, 5% AFB2, 10% AFG1 and 17.5% AFG2. All isolates of F. graminearum sensu lato produced DON and 15-AcDON. The results from this study contribute to the knowledge of mycobiota and mycotoxins present in wheat silage.

Endophytic bacteria from wheat grain as biocontrol agents of Fusarium graminearum and deoxynivalenol production in wheat

In Uruguay, Fusarium graminearum is the most common species that infects wheat and is responsible for Fusarium head blight (FHB) and contamination of grain with deoxynivalenol (DON). The aim of this work was to select bacterial endophytes isolated from wheat grain to evaluate their antagonistic ability against F. graminearum and DON production in vitro and under field conditions. Four strains identified as Bacillus megaterium (BM1) and Bacillus subtilis (BS43, BSM0 y BSM2) significantly reduced fungal growth and spore germination of F. graminearum. This antagonist activity remained unchanged after the bacterial cultures were heat treated. Under field conditions, treatments with antagonist BM1 was the most effective, reducing the FHB incidence and severity by 93 and 54 %, respectively, and the production of DON by 89.3 %.