Fate of trichothecene mycotoxins during the processing: milling and baking.

Toxic secondary metabolites produced by fungi representing Fusarium genus are common contaminants in cereals worldwide. To estimate the dietary intake of these trichothecene mycotoxins, information on their fate during cereal processing is needed. Up-to-date techniques such as high-performance liquid chromatography (HPLC) coupled with tandem mass spectrometry (LC-MS/MS) was used for the analysis of seven trichothecenes (deoxynivalenol, nivalenol, HT-2 toxin, T-2 toxin, 15- and 3-acetyldeoxynivalenol, and fusarenon-X) in bread production chain (wheat grains, intermediate products collected during milling and baking process, breads). Regardless of whether the grains were naturally infected or artificially inoculated by Fusarium spp. in the field, the fractions obtained from the grain-cleaning procedure contained the highest mycotoxin levels. During milling the highest concentrations of deoxynivalenol were found in the bran, the lowest in the reduction flours. Baking at 210 degrees C for 14 min had no significant effect on deoxynivalenol levels. The rheological properties of dough measured by fermentograph, maturograph, oven rise recorder, and laboratory baking test were carried out, and based on the obtained results the influence of mycotoxin content on rheological behaviour was investigated.     

Fate of trichothecene mycotoxins during the processing: Milling and baking

Toxic secondary metabolites produced by fungi representing Fusarium genus are common contaminants in cereals worldwide. To estimate the dietary intake of these trichothecene mycotoxins, information on their fate during cereal processing is needed. Up-to-date techniques such as high-performance liquid chromatography (HPLC) coupled with tandem mass spectrometry (LC-MS/MS) was used for the analysis of seven trichothecenes (deoxynivalenol, nivalenol, HT-2 toxin, T-2 toxin, 15- and 3-acetyldeoxynivalenol, and fusarenon-X) in bread production chain (wheat grains, intermediate products collected during milling and baking process, breads). Regardless of whether the grains were naturally infected or artificially inoculated by Fusarium spp. in the field, the fractions obtained from the grain-cleaning procedure contained the highest mycotoxin levels. During milling the highest concentrations of deoxynivalenol were found in the bran, the lowest in the reduction flours. Baking at 210°C for 14 min had no significant effect on deoxynivalenol levels. The rheological properties of dough measured by fermentograph, maturograph, oven rise recorder, and laboratory baking test were carried out, and based on the obtained results the influence of mycotoxin content on rheological behaviour was investigated.     

Distribution of deoxynivalenol and nivalenol in milling fractions from fusarium-infected Japanese wheat cultivars

The fate of the Fusarium mycotoxins deoxynivalenol and nivalenol during the milling of Japanese wheat cultivars artificially infected with Fusarium was investigated. Grain samples with different mycotoxin concentrations were milled using a laboratory-scale test mill to produce eight fractions: three breaking flours (1B, 2B, and 3B), three reduction flours (1M, 2M, and 3M), wheat bran, and wheat shorts. Patent flour for human consumption was made from the 1B, 2B, 1M, and 2M flours, and low-grade flour was made from 3B and 3M flours. The four resulting samples (patent flour, low-grade flour, bran, and shorts) were analyzed for deoxynivalenol and/or nivalenol with an in-house validated analytical method using high-performance liquid chromatography with UV absorbance detection. In samples with different mycotoxin concentrations, the distribution of those toxins differed among the milling fractions. Grains with a lower level of contamination produced bran and shorts samples with a high relative concentration of nivalenol. A high percentage of nivalenol was found in patent flour, followed by bran. Contrary to the less-contaminated sample, the concentration of nivalenol in moderately contaminated grain was high only in the shorts sample. The highest percentage of deoxynivalenol and nivalenol was observed in the patent flour. The results of this study indicate that the distribution of deoxynivalenol and nivalenol in milled Japanese wheat could be influenced by the contamination level of the original grain, and the milling process is not always effective for removal of toxins from wheat grains.     

Mycotoxin contamination of cereal grain commodities in relation to climate in North West Europe

This study aimed to investigate mycotoxin contamination of cereal grain commodities for feed and food production in North Western Europe during the last two decades, including trends over time and co-occurrence between toxins, and to assess possible effects of climate on the presence of mycotoxins. For these aims, analytical results related to mycotoxin contamination of cereal grain commodities, collected in the course of national monitoring programmes in Finland, Sweden, Norway and the Netherlands during a 20-year period, were gathered. Historical observational weather data, including daily relative humidity, rainfall and temperature, were obtained from each of these four countries. In total 6382 records, referring to individual sample results for mycotoxin concentrations (one or more toxins) in cereal grains were available. Most records referred to wheat, barley, maize and oats. The most frequently analysed mycotoxins were deoxynivalenol, 3-acetyl-deoxynivalenol, nivalenol, T-2 toxin, HT-2 toxin and zearalenone. Deoxynivalenol had the highest overall incidence of 46%, and was mainly found in wheat, maize and oats. Mycotoxins that showed co-occurrence were: deoxynivalenol and 3-acetyl-deoxynivalenol in oats; deoxynivalenol and zearalenone in maize and wheat; and T-2 toxin and HT-2 toxin in oats. The presence of both deoxynivalenol and zearalenone in wheat increased with higher temperatures, relative humidity and rainfall during cultivation, but the presence of nivalenol was negatively associated with most of these climatic factors. The same holds for both nivalenol and deoxynivalenol in oats. This implies that climatic conditions that are conducive for one toxin may have a decreasing effect on the other. The presence of HT-2 toxin in oats showed a slight decreasing trends over time, but significant trends for other toxins showed an increasing presence during the last two decades. It is therefore useful to continue monitoring of mycotoxins. Obtained results can be used for development of predictive models for presence of mycotoxins in cereal grains.     

Stability of mycotoxins during food processing

The mycotoxins that commonly occur in cereal grains and other products are not completely destroyed during food processing operations and can contaminate finished processed foods. The mycotoxins most commonly associated with cereal grains are aflatoxins, ochratoxin A, fumonisins, deoxynivalenol and zearalenone. The various food processes that may have effects on mycotoxins include sorting, trimming, cleaning, milling, brewing, cooking, baking, frying, roasting, canning, flaking, alkaline cooking, nixtamalization, and extrusion. Most of the food processes have variable effects on mycotoxins, with those that utilize the highest temperatures having greatest effects. In general the processes reduce mycotoxin concentrations significantly, but do not eliminate them completely. However, roasting and extrusion processing show promise for lowering mycotoxin concentrations, though very high temperatures are needed to bring about much of a reduction in mycotoxin concentrations. Extrusion processing at temperatures greater than 150 degrees C are needed to give good reduction of zearalenone, moderate reduction of alfatoxins, variable to low reduction of deoxynivalenol and good reduction of fumonisins. The greatest reductions of fumonisins occur at extrusion temperatures of 160 degrees C or higher and in the presence of glucose. Extrusion of fumonisin contaminated corn grits with 10% added glucose resulted in 75-85% reduction in Fumonisin B(1) levels. Some fumonisin degredation products are formed during extrusion, including small amounts of hydrolyzed Fumonisin B(1) and N-(Carboxymethyl) - Fumonisin B(1) and somewhat higher amounts of N-(1-deoxy-d-fructos-1-yl) Fumonisin B(1) in extruded grits containing added glucose. Feeding trial toxicity tests in rats with extruded fumonisin contaminated corn grits show some reduction in toxicity of grits extruded with glucose.     

Distribution of Fusarium mycotoxins in UK wheat mill fractions

The EU has set maximum limits for the Fusarium mycotoxins, deoxynivalenol (DON) and zearalenone (ZON). The maximum permitted level decreases from unprocessed wheat, through intermediary products, e.g. flour, to finished products such as bakery goods and breakfast cereals. It is, therefore, important to understand the effects of processing on the mycotoxin distribution in mill fractions. Between 2004 and 2007, samples were taken at commercial flour mills at various points in the milling process and analysed for trichothecenes and ZON. Samples with a range of mycotoxin concentrations harvested in 2004 and 2005 were processed in a pilot mill and the mycotoxins in the different mill fractions quantified. In the commercial samples, DON was the predominant mycotoxin with highest levels detected in the bran fraction. Analysis of the pilot mill fractions identified a significant difference between the two years and between mycotoxins. The proportion of DON and nivalenol in the mill fractions varied between years. DON and nivalenol were higher in flour fractions and lower in bran and offal in samples from 2004 compared to samples from 2005. This may be a consequence of high rainfall pre-harvest in 2004 resulting in movement of these mycotoxins within grains before harvest. There was no significant difference in the distribution of ZON within mill fractions between the two years. For DON, higher concentrations in the grain resulted in a greater proportion of DON within the flour fractions. Understanding the factors that impact on the fractionation of mycotoxins during milling will help cereal processors to manufacture products within legislative limits.     

Occurrence of Fusarium Head Blight species and Fusarium mycotoxins in winter wheat in the Netherlands in 2009

Most recent information on the occurrence of Fusarium Head Blight species and related mycotoxins in wheat grown in the Netherlands dates from 2001. This aim of this study was to investigate the incidence and levels of Fusarium Head Blight species and Fusarium mycotoxins, as well as their possible relationships, in winter wheat cultivated in the Netherlands in 2009. Samples were collected from individual fields of 88 commercial wheat growers. Samples were collected at harvest from 86 fields, and 2 weeks before the expected harvest date from 21 fields. In all, 128 samples, the levels of each of seven Fusarium Head Blight species and of 12 related mycotoxins were quantified. The results showed that F. graminearum was the most frequently observed species at harvest, followed by F. avenaceum and M. nivale. In the pre-harvest samples, only F. graminearum and M. nivale were relevant. The highest incidence and concentrations of mycotoxins were found for deoxynivalenol, followed by zearalenone and beauvericin, both pre-harvest and at harvest. Other toxins frequently found - for the first time in the Netherlands - included T-2 toxin, HT-2 toxin, and moniliformin. The levels of deoxynivalenol were positively related to F. graminearum levels, as well as to zearalenone levels. Other relationships could not be established. The current approach taken in collecting wheat samples and quantifying the presence of Fusarium Head Blight species and related mycotoxins is an efficient method to obtain insight into the occurrence of these species and toxins in wheat grown under natural environmental conditions. It is recommended that this survey be repeated for several years to establish inter-annual variability in both species composition and mycotoxin occurrence.     

Modelling mycotoxin formation by Fusarium graminearum in maize in The Netherlands

The predominant species in maize in temperate climates is Fusarium graminearum, which produces the mycotoxins deoxynivalenol and zearalenone. Projected climate change is expected to affect Fusarium incidence and thus the occurrence of these mycotoxins. Predictive models may be helpful in determining trends in the levels of these mycotoxins with expected changing climatic conditions. The aim of this study was to develop a model describing fungal infection and subsequent growth as well as the formation of deoxynivalenol and zearalenone in maize in The Netherlands. For this purpose, a published Italian model was used as a starting point. This model is a mixed empiric-mechanistic model that describes fungal infection during silking (based on wind speed and rainfall) and subsequent germination, growth and toxin formation (depending on temperature and water availability). Model input uses weather parameters and crop management factors, such as maize hybrid, sowing date, flowering period and harvest date. Model parameter values were obtained by fitting these parameters to deoxynivalenol and zearalenone measurements in Dutch maize, using national mycotoxin data from the years 2002-2007. The results showed that the adapted model is capable of describing the trend in average deoxynivalenol and zearalenone levels over these years. Validation with external data is needed to verify model outcomes. It is expected that the current model can be used to estimate the effect of projected climate change on trends in deoxynivalenol and zearalenone levels in the coming years.     

Effects of processing on mycotoxin stability in cereals

The mycotoxins that generally occur in cereals and other products are not completely destroyed during food‐processing operations and can contaminate finished processed foods. The mycotoxins most usually associated with cereal grains are aflatoxins, ochratoxins, deoxynivalenol, zearalenone and fumonisins. The various food processes that may have effects on mycotoxins include cleaning, milling, brewing, cooking, baking, frying, roasting, flaking, alkaline cooking, nixtamalization, and extrusion. Most of the food processes have variable effects on mycotoxins, with those that utilize high temperatures having the greatest effects. In general, the processes reduce mycotoxin concentrations significantly, but do not eliminate them completely. This review focuses on the effects of various thermal treatments on mycotoxins. © 2014 Society of Chemical Industry     

Impact of durum wheat milling on deoxynivalenol distribution in the outcoming fractions

The milling behaviour of two naturally infected samples of durum wheat grain with contrasting levels of mycotoxins was studied. Although the two samples showed a similar milling behaviour, an increase of ～20% in deoxynivalenol (DON) levels was found in semolina from the sample containing the higher level of mycotoxin. However, even if the highest concentration of DON was found in fractions originating from the grain outer layers, the mycotoxin contamination in semolina and flours were not related to the amount of two compounds (ash or phytic acid) used to monitor these external tissues. The presence of the trichothecene-producing fungi in the inner-most semolina fraction was also shown using specific DNA primers and PCR amplification. Comparison of DON concentrations in the feed stock and corresponding output at each milling step or grinding of semolina fractions followed by sizing showed that concentration of mycotoxin occurs in the finest particles at the first processing steps. Therefore, DON contamination of milling fractions is not simply due to the presence of peripheral grain tissues.     

Mycotoxins in infant/toddler foods and breakfast cereals in the US retail market

The objective of this study was to conduct a mycotoxin survey of commercial infant/toddler foods (cereals and teething biscuits) and breakfast cereals in the United States. A total of 215 retail samples were collected from three geographical locations and analysed for aflatoxins, fumonisins, deoxynivalenol, HT-2 toxin, ochratoxin A, T-2 toxin, and zearalenone using a stable isotope dilution liquid-chromatography tandem mass spectrometry (LC-MS/MS) method. One or more mycotoxins were found in 69% (101/147) of the infant/toddler foods and 50% (34/68) of breakfast cereals. Mycotoxin co-occurrence was observed in 12% of infant/toddler foods and 32% of breakfast cereals. However, the concentrations of detected mycotoxins were lower than the current FDA action and guidance levels. Aflatoxins and HT-2 toxin were not detected in any of the samples, while deoxynivalenol was the most frequently detected mycotoxin. Rice-based cereals appeared to be less susceptible to mycotoxin contamination than other cereal types.     

Effect of Processing on Mycotoxin Content in Grains

Mycotoxins that commonly occur in cereal grains and other products can contaminate finished processed foods on account of their high toxicity. The mycotoxins that are commonly associated with food grains include aflatoxins, ochratoxin A, fumonisins, deoxynivalenol, and zearalenone. Various food-processing operations include sorting, trimming, cleaning, cooking, baking, frying, roasting, flaking, and extrusion that have variable effects on mycotoxins. The nature of the processing operation viz. physical, chemical, or thermal plays an important role in this; usually, the processes that utilize the higher temperatures have greater effects on mycotoxin dissipation. In general, the processes are known to reduce mycotoxin concentrations significantly, but do not eliminate them completely. However, roasting and extrusion processing result in lowest mycotoxin concentrations, since these involve higher temperatures. It is observed that very high temperatures are needed to bring about high reduction in mycotoxin concentrations, approaching acceptable background levels. The treatment with chemicals like ammonia, bicarbonate, citric acid, or sodium bisulfite is also effective in resulting in significant decline in mycotoxin concentrations.     

Occurrence and preventive strategies to control mycotoxins in cereal‐based food

Mycotoxins contamination in cereal‐based food is ubiquitous according to systematic review of the scientific documentation of worldwide mycotoxin contamination in cereal and their products between 2008 and 2018, thus representing food safety issue especially in developing tropical countries. Food processing plays a vital role to prevent mycotoxin contamination in food. Therefore, it is with great urgency to develop strategies to inhibit fungi growth and mycotoxin production during food processing. This review begins by discussing physicochemical properties of five most common mycotoxins (aflatoxins, fumonisins, ochratoxins, deoxynivalenol, and zearalenone) found in cereal grains, regulation for mycotoxins in food, and their potential negative impact on human health. The fate of mycotoxins during major cereal‐based food processing including milling, breadmaking, extrusion, malting, and brewing was then summarized. In the end, traditional mitigation strategies including physical and chemical and potential application of biocontrol agent and essential oil nanoemulsions that can be applied during food processing were discussed. It indicated that no single method is currently available to completely prevent mycotoxin contamination in cereal foods.     

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.     

Fundamental study on the influence of Fusarium infection on quality and ultrastructure of barley malt

Barley infection with Fusarium species has been a long standing problem for the malting and brewing industries. In this study, we evaluate the impact of Fusarium culmorum infected raw barley on the final malt quality. Barley grains were infected for 5 days at optimum fungal growth conditions. Grains were fully characterized and compared to standard barley grains. Due to fungal infection, germinative energy of infected barley grains decreased by 45%; its water sensitivity increased dramatically, and grains accumulated 199 μg/kg of deoxynivalenol (DON). Barley grains were subsequently malted for 8 days, fully characterized and compared to standard malt grains. Fungal growth behavior was evaluated during malting using a PCR-based assay and mycotoxins were measured using HPLC. Fungal biomass increased in grains, during all stages of malting. Infected malt accumulated 8-times its DON concentration during malting. Kernel ultrastructure was evaluated using scanning electron and confocal laser scanning microscopy. Infected malt grains were characterized by extreme structural proteolytic, (hemi)-cellulolytic and starch deterioration with increased friability and fragmentation. Infected grains had higher protease and β-glucanase activities, lower amylase activity, a greater proportion of free amino and soluble nitrogen, and a lower β-glucan content. Malt loss was over 27% higher in infected malt in comparison to the control. The results of this study revealed that 20% F. culmorum infected barley kernels lead to a significant reduction in malt quality as well as mycotoxin formation.     

Naturally occurring Fusarium toxins in New Zealand maize

Twenty samples of maize collected from healthy growing crops and at harvest time and during storage were screened for four Fusarium toxins (deoxynivalenol, diacetoxyscirpenol, T-2 toxin and zearalenone) by gas chromatography-mass spectrometry and thin-layer chromatography. Seventeen samples (85%) contained one or more of these toxins. Zearalenone was present in 15 samples at levels ranging between 0.1 and 16 ppm. Deoxynivalenol, diacetoxyscirpenol and T-2 toxin were found in 11, 6 and 13 samples respectively, all at levels below 1 ppm. This work documents the first reported natural occurrence of Fusarium toxins in New Zealand maize, and it is concluded that all four of the mycotoxins studied are prevalent in apparently healthy standing crops as well as in stored maize.     

The contamination of the 1986-1988 wheat harvests with deoxynivalenol (vomitoxin)

The authors used high-performance liquid chromatography to estimate the content of deoxynivalenol (vomitoxin) trichothecene mycotoxin in 175 samples of wheat harvested in the Krasnodar Territory in 1986-1988. High incidence rates and levels of wheat intoxication have been recorded: 42.8% in 1986, 25% in 1987, and 80.28% of wheat samples in 1988 contained deoxynivalenol in concentrations exceeding MPC (1 mg/kg). A correlation was noted between the degree of wheat affection with Fusarium and the level of its intoxication with deoxynivalenol. A conclusion has been made on the necessity of using the criteria of the degree of wheat affection with Fusarium and the level of its intoxication with deoxynivalenol in hygienic recommendations for safe utilization of fusarial grain for food purposes.     

Studies into the occurrence of some trichothecene mycotoxins in UK home-grown wheat and in imported wheat

A total of 199 UK home-grown wheat samples collected over three harvests (1980–82 inclusive) and 33 imported wheat samples were analysed for the presence of seven trichothecene mycotoxins (nivalenol, deoxynivalenol, fusarenon-x, neosolaniol, diacetoxyscirpenol, HT-2 toxin and T-2 toxin). Analysis was performed by a gas–liquid chromatographic method and positive results greater than 0.1 mg kg^?1 were confirmed by mass spectrometry. The only mycotoxin detected in any of the samples was deoxynivalenol (vomitoxin) which occurred in 32 out of 199 UK home-grown wheats at levels ranging from 0.02 to 0.40 mg kg^?1 and 23 out of 33 imported wheats at levels ranging from 0.02 to 1.32 mg kg^?1. Microbiological evidence suggests that the lower incidence and levels of deoxynivalenol in UK, other EEC and Western Canadian wheat compared with Eastern Canadian and Midwest US wheat may be caused by a geographical variation in the distribution of Fusarium species.     

Fluorescence polarization as a tool for the determination of deoxynivalenol in wheat.

The mould Fusarium graminearum is found worldwide as a pathogen of cereal grains, in particular of wheat and maize, and it produces a mycotoxin known as deoxynivalenol (DON or vomitoxin). Each year, the presence of this compound and related trichothecenes causes substantial losses to agricultural productivity. Rapid methods for the measurement of the toxin in grains are required to monitor and divert effectively contaminated grain from the food supply. A fluorescence polarization (FP) immunoassay using a previously described monoclonal antibody for DON was developed. The assay was based on the competition of unlabeled DON from a sample with a fluorescently tagged DON, DON-fluorescein (DON-FL), for a DON-specific monoclonal antibody in solution. The FP of the tagged DON was increased upon binding with the antibody. In the presence of free toxin, less of the DON-FL was bound and the polarization signal was decreased. The assays were very simple to perform, requiring only mixing of an aqueous extract of wheat with the DON-FL and antibody. The sensitivity of the assay was strongly dependent upon the time between mixing of the sample with the tracer and measurement of the fluorescence polarization, with midpoints for the competition curves ranging from 0.03 microg ml(-1) with a 15-s incubation to >1 microg ml(-1) with a 12-min incubation. Samples of wheat naturally contaminated with DON were evaluated by FP and by an HPLC-UV method, with a good correlation (r2 = 0.97). Although the FP method tended to overestimate DON slightly in the wheat samples, by approxiamtely 20%, the assay was easy to use and very useful for the screening of wheat.     

Trichothecenes, ochratoxin A and zearalenone contamination and Fusarium infection in Finnish cereal samples in 1998

The occurrences and concentrations of trichothecenes, ochratoxin A and zearalenone in Finnish cereal samples are presented in this study. Furthermore, infections by moulds, especially Fusarium contamination of grains in the same samples, are reported. In total 68 cereal samples, including 43 rye, 4 wheat, 15 barley and 6 oats samples, were collected after a cool and very rainy growing season in 1998. A gas chromatograph combined with a mass spectrometric detector was used for determination of seven different trichothecenes. A high performance liquid chromatograph with a fluorescence detector was used for ochratoxin A and zearalenone determination. For the identification of moulds, the grain samples were incubated and the moulds were isolated and identified by microscopy. The analytical methods were validated for mycotoxin analysis and they were found to be adequately reliable and sensitive. Heavy rainfalls in the summer and autumn of 1998 caused abundant Fusarium mould infection in Finnish cereals, particularly in rye. Fusarium avenaceum was the most common Fusarium species found in cereals. However, the mycotoxin concentrations were very low and only deoxynivalenol, nivalenol and HT-2 toxin were detected. Deoxynivalenol was detected in 54 samples in the concentration range 5-111 µg/kg. Nivalenol and HT-2 toxin were detected in three and two samples, respectively, in the concentration range 10-20 µg/kg.