Determination of mycotoxin exposure in Germany using an LC‐MS/MS multibiomarker approach

Interaction between the three frequently co-occurring Fusarium mycotoxins in rats

To test the complex, acute biochemical effects of combined, naturally co-occurring fusariotoxins, a 5-day rat study was performed. Mycotoxin treatment was invented by intraperitoneal injection: FB₁ (F): 9 µg/animal/day (approx. 30 µg/kg bw/day), DON (D): 16.5 µg/animal/day (approx. 55 µg/kg bw/day) and ZEN (Z): 12.75 µg/animal/day (approx. 42.5 µg/kg bw/day). The binary groups (FB₁ and DON [FD], FB₁ and ZEN [FZ] and DON and ZEN [DZ]) as well as the ternary (FB₁ , DON and ZEN [FDZ]) group were dosed at the same combined level as the individual mycotoxins. Body weight, feed intake and mortality were not affected by any of the treatments. FB₁ and DON in combination (FD) increased the plasma aspartate aminotransferase activity synergistically (compared to the individual FB₁ and DON). In the liver, both the total glutathione (GSH) and the glutathione peroxidase (GPx) activity were increased (p < 0.05) by the binary FB₁ and ZEN (FZ) and the DON and ZEN (DZ) groups as well as the ternary FB₁ , DON and ZEA group (FDZ) compared to the control. The GSH level of the ternary group was significantly increased compared to the FB₁ group, whereas the GPx activity of the ternary group was significantly increased compared to all three the individual mycotoxin groups. The Bliss independence method revealed synergism between DON and ZEN (DZ), as well as FB₁ and DON (FD) on liver GPx activity. None of the toxins alone or in combination exerted strong genotoxicity on lymphocytes, neither on the gross histopathological characteristics. However, even at these low levels acute exposure of more than one of these mycotoxins (FB₁ , DON and ZEN) affected metabolic and detoxification changes.

Mycotoxin exposure and adverse reproductive health outcomes in Africa: a review

It is well established that mycotoxin exposure can have adverse effects on reproductive health resulting to poor reproductive potential. The most studied mycotoxin in relation to poor reproductive health in humans is aflatoxin, although fumonisins, trichothecenes and zearalenone have also been reported to impair reproductive function and cause abnormal foetal development. These potent fungal toxins contaminate many food products making them a prominent agricultural, food safety and public health challenge, especially in Africa due to little or lack of mycotoxin regulation in agricultural products. Neonates can be exposed to aflatoxins in utero, as the toxins pass from mother to the foetus through the placenta. This exposure may continue during breast feeding, to the introduction of weaning foods, and then foods taken by adults. The consequences of aflatoxin exposure in mothers, foetus and children are many, including anaemia in pregnancy, low birth weight, interference with nutrient absorption, suppression of immune function, child growth retardation and abnormal liver function. In males, reports have indicated a possible relationship between aflatoxin exposure and poor sperm quality culminating in infertility. Maternal exposure to fumonisin during early pregnancy has been associated with increased risk of neural tube defects among newborns in regions where maize is the common dietary staple with the possibility of chronic fumonisin exposure. Furthermore, zearalenone has been linked to precocious puberty and premature thelarche in girls, correlating with extremely high serum oestrogen levels. This review presents an overview of the several reports linking aflatoxins, fumonisins, trichothecenes, and zearalenone exposure to poor reproductive health outcomes in Africa, with emphasis on birth outcomes, foetal health and infertility.

Exposure Assessment to Mycotoxins in a Portuguese Fresh Bread Dough Company by Using a Multi-Biomarker Approach

Mycotoxins are toxic mold metabolites that can persist in environment long after the fungi species responsible for their production disappear. Critical workplace for mycotoxins presence has already been studied and nowadays it is possible to recognize that exposure to mycotoxins through inhalation occurs due to their presence in dust. This study aimed to assess occupational co-exposure to multiple mycotoxins in a fresh bread dough company, an occupational setting not studied until now. Occupational exposure assessment to mycotoxins was done using a LC-MS/MS urinary multi-biomarker approach. Twenty-one workers and nineteen individuals that were used as controls participated in the study. Workers/controls (spot-urine) and environment (settled dust) samples were collected and analyzed. Concerning workers group, DON-GlcA, and OTA were the most prevalent biomarkers (>LOD), 66% and 90.5%, respectively. In the control group, OTA was also one of the most detected (68%) followed by CIT (58%) and DON-GlcA (58%). DON was the mycotoxin measured in high amounts in the settled dust sample (58.2 ng/g). Both workers and controls are exposed to several mycotoxins simultaneously. The workers group, due to their high contact with flour dust, revealed a higher exposure to DON. Considering these results, risk management measures must be applied including specific and adequate health surveillance programs in order to avoid exposure and consequently the associated health consequences.

High-throughput and sensitive determination of urinary zearalenone and metabolites by UPLC-MS/MS and its application to a human exposure study

Biomarker-based strategies to assess human exposure to mycotoxins have gained increased acceptance in recent years. In this study, an improved method based on UPLC-MS/MS following 96-well μElution solid-phase extraction was developed and validated for the sensitive and high-throughput determination of zearalenone (ZEN) and its five metabolites α-zearalenol (α-ZEL), β-zearalenol (β-ZEL), α-zearalanol (α-ZAL), β-zearalanol (β-ZAL), and zearalanone (ZAN) in human urine samples, using ¹³C-ZEN as an internal standard for accurate quantification. Two plates of samples (n = 192) could be processed within 2 h, and baseline separation of all the analytes was achieved in a total runtime of 6 min. The proposed method allowed ZEN and its metabolites to be sensitively determined in a high-throughput way for the first time, and with significantly improved efficiency and accuracy with respect to existing methods. The limits of detection (LODs) and limits of quantitation (LOQs) ranged from 0.02 to 0.06 ng mL^-1 and from 0.05 to 0.2 ng mL^-1, respectively. The recoveries for the spiked samples were from 87.9 to 100%, with relative standard deviations (RSDs) of less than 7%. 301 urine samples collected from healthy volunteers aged 0-84 years in China were analyzed with and without enzyme hydrolysis to determine total and free ZEN biomarkers, respectively. ZEN, ZAN, α-ZEL, and β-ZEL were detected in 71.4% of the samples at levels of 0.02-3.7 ng mL^-1 after enzyme hydrolysis. The estimated mean probable daily intake (PDI) was much lower than the tolerable daily intake (TDI). Adolescents had higher exposure than children, adults, and the elderly. Graphical abstract ᅟ.

Transport of enniatin B and enniatin B1 across the blood-brain barrier and hints for neurotoxic effects in cerebral cells

Enniatins are common contaminants of food and feed and belong to the group of the "emerging" mycotoxins, which are produced by various Fusarium species. Although a wide range of toxic effects, like antibacterial, antifungal, insecticidal and cytotoxic properties, have been described in vitro, so far, no cases of mycotoxicosis connected to enniatins in vivo are reported. Among this group of mycotoxins, enniatin B and enniatin B1 are the most prevalent compounds and therefore are present in the human diet. Enniatins can reach systemic circulation, thus, the investigation of possible neurotoxic effects is of importance. Different cerebral cells were used to address effects on cell death having an impact on the blood-brain barrier. The influence of enniatin B and enniatin B1 on cellular viability was examined via Cell Counting kit-8 assay (CCK-8) in three different cell types of the blood-brain barrier: porcine brain capillary endothelial cells (PBCEC), human brain microvascular endothelial cells (HBMEC) and human astrocytoma cells (CCF-STTG1). CCF-STTG1 cells were more sensitive to enniatin B (IC50 = 8.9 μM) and enniatin B1 (IC50 = 4.4 μM) than both endothelial cell types. In CCF-STTG1 cells, caspase-3 activation and lactate dehydrogenase (LDH) release were evaluated. Both compounds did not induce any LDH release and only enniatin B increased caspase-3 activity as a marker for apoptosis. The transport kinetics of enniatin B and enniatin B1 across the blood-brain barrier in vitro were evaluated using PBCEC, cultivated on Transwell® filter inserts. Analysis of the apical and the basolateral compartment by high performance liquid chromatography-mass spectrometry revealed high influx rates for enniatin B and enniatin B1. Thus, both compounds can reach the brain parenchyma where neurotoxic effects cannot be ruled out.

Risk assessment of deoxynivalenol in high-risk area of China by human biomonitoring using an improved high throughput UPLC-MS/MS method

A risk assessment of deoxynivalenol (DON) was recently conducted for the residents in Henan province, China, where wheat as the staple food are highly consumed. A high-throughput sensitive UPLC-MS/MS method following 96-well μElution solid-phase extraction (SPE) were developed and validated for the determination of DON biomarkers in human urine. Isotope labelled internal standard, 13C-DON, was used for accurate quantification. Urinary samples collected from 151 healthy Chinese aged 2-78 years were processed with and without enzyme hydrolysis to determine total and free biomarkers, respectively. DON, and de-epoxy-deoxynivalenol (DOM-1) to a lesser extent, can be frequently detected in these samples both with and without enzyme hydrolysis. Free DOM-1 was detected at low level in human urine for the first time. Total DON was detected in all samples with a mean concentration at 47.6 ng mL-1. The mean and median probable daily intakes (PDI) for the whole participants, estimated to be 1.61 μg/kg bw and 1.10 μg/kg bw, both exceeded the PMTDI (1 μg/kg bw/day), indicating a potential risk for the residents in this area, especially for children and adolescents.

Appropriateness to set a group health-based guidance value for fumonisins and their modified forms

The EFSA Panel on Contaminants in the Food Chain (CONTAM) established a tolerable daily intake (TDI) for fumonisin B1 (FB 1) of 1.0 μg/kg body weight (bw) per day based on increased incidence of megalocytic hepatocytes found in a chronic study with mice. The CONTAM Panel considered the limited data available on toxicity and mode of action and structural similarities of FB 2-6 and found it appropriate to include FB 2, FB 3 and FB 4 in a group TDI with FB 1. Modified forms of FBs are phase I and phase II metabolites formed in fungi, infested plants or farm animals. Modified forms also arise from food or feed processing, and include covalent adducts with matrix constituents. Non-covalently bound forms are not considered as modified forms. Modified forms of FBs identified are hydrolysed FB 1-4 (HFB 1-4), partially hydrolysed FB 1-2 (pHFB 1-2), N-(carboxymethyl)-FB 1-3 (NCM-FB 1-3), N-(1-deoxy-d-fructos-1-yl)-FB 1 (NDF-FB 1), O-fatty acyl FB 1, N-fatty acyl FB 1 and N-palmitoyl-HFB 1. HFB 1, pHFB 1, NCM-FB 1 and NDF-FB 1 show a similar toxicological profile but are less potent than FB 1. Although in vitro data shows that N-fatty acyl FBs are more toxic in vitro than FB 1, no in vivo data were available for N-fatty acyl FBs and O-fatty acyl FBs. The CONTAM Panel concluded that it was not appropriate to include modified FBs in the group TDI for FB 1-4. The uncertainty associated with the present assessment is high, but could be reduced provided more data are made available on occurrence, toxicokinetics and toxicity of FB 2-6 and modified forms of FB 1-4.

Mycotoxins co-contamination: Methodological aspects and biological relevance of combined toxicity studies

Mycotoxins are secondary fungal metabolites produced mainly by Aspergillus, Penicillium, and Fusarium. As evidenced by large-scale surveys, humans and animals are simultaneously exposed to several mycotoxins. Simultaneous exposure could result in synergistic, additive or antagonistic effects. However, most toxicity studies addressed the effects of mycotoxins separately. We present the experimental designs and we discuss the conclusions drawn from in vitro experiments exploring toxicological interactions of mycotoxins. We report more than 80 publications related to mycotoxin interactions. The studies explored combinations involving the regulated groups of mycotoxins, especially aflatoxins, ochratoxins, fumonisins, zearalenone and trichothecenes, but also the "emerging" mycotoxins beauvericin and enniatins. Over 50 publications are based on the arithmetic model of additivity. Few studies used the factorial designs or the theoretical biology-based models of additivity. The latter approaches are gaining increased attention. These analyses allow determination of the type of interaction and, optionally, its magnitude. The type of interaction reported for mycotoxin combinations depended on several factors, in particular cell models and the tested dose ranges. However, synergy among Fusarium toxins was highlighted in several studies. This review indicates that well-addressed in vitro studies remain valuable tools for the screening of interactive potential in mycotoxin mixtures.

Enniatin B and ochratoxin A in the blood serum of workers from the waste management setting

The waste management occupational environment is recognized by the simultaneous presence of several substances and biologic agents. Therefore, workers are exposed simultaneously to multiple contaminants. Occupational exposure to aflatoxin B₁ in one Portuguese waste sorting plant was already reported. However, besides this mycotoxin, data regarding fungal contamination showed that exposure to other mycotoxins could be expected. A study was developed to analyze if exposure to other mycotoxins besides aflatoxin B₁ was occurring in the workers from the waste sorting plant previously assessed and to discuss how these findings need to be considered in the risk assessment process. In addition to aflatoxin B₁ detected previously by ELISA, two additional mycotoxins and one mycotoxin degradation product were detected and quantified by a multi-mycotoxin HPLC-MS/MS approach: Enniatin B and ochratoxin A as well as 2'R-ochratoxin A. Besides the confirmation of co-exposure to several mycotoxins, results probably indicate different exposure routes for the mycotoxins reported.

Comparison of Data from a Single-Analyte and a Multianalyte Method for Determination of Urinary Total Deoxynivalenol in Human Samples

Deoxynivalenol (DON) exposure is estimated by the combined measures of urinary DON and DON-glucuronides. In this study, data from single-mycotoxin (SM) and a multimycotoxin (MM) methods were compared for 256 Swedish adult urine samples. Both methods included β-glucuronidase predigestion, immunoaffinity enrichment, and LC-MS/MS. However, the specific reagents, apparatus, and conditions were not identical in part because the MM method measures additional mycotoxins. DON was detected in 88 and 63% of samples using the SM and MM methods, respectively, with the following mean and median concentrations: SM, mean = 5.0 ng/mL, SD = 7.4, range of positives = 0.5-60.2 ng/mL, median = 2.5 ng/mL, IQR = 1.0-5.5 ng/mL; MM, mean = 4.4 ng/mL, SD = 12.9, range of positives = 0.5-135.2 ng/mL, median = 0.8 ng/mL, IQR = 0.3-3.5. Linear regression showed a significant, albeit modest, correlation between the two measures (p = 0.0001, r = 0.591). The differences observed may reflect subtle handling differences in DON extraction and quantitation between the methods.

Worldwide Occurrence of Mycotoxins in Cereals and Cereal-Derived Food Products: Public Health Perspectives of Their Co-occurrence

Cereal grains and their processed food products are frequently contaminated with mycotoxins. Among many, five major mycotoxins of aflatoxins, ochratoxins, fumonisins, deoxynivalenol, and zearalenone are of significant public health concern as they can cause adverse effects in humans. Being airborne or soilborne, the cosmopolitan nature of mycotoxigenic fungi contribute to the worldwide occurrence of mycotoxins. On the basis of the global occurrence data reported during the past 10 years, the incidences and maximum levels in raw cereal grains were 55% and 1642 μg/kg for aflatoxins, 29% and 1164 μg/kg for ochratoxin A, 61% and 71,121 μg/kg for fumonisins, 58% and 41,157 μg/kg, for deoxynivalenol, and 46% and 3049 μg/kg for zearalenone. The concentrations of mycotoxins tend to be lower in processed food products; the incidences varied depending on the individual mycotoxins, possibly due to the varying stability during processing and distribution of mycotoxins. It should be noted that more than one mycotoxin, produced by a single or several fungal species, may occur in various combinations in a given sample or food. Most studies reported additive or synergistic effects, suggesting that these mixtures may pose a significant threat to public health, particularly to infants and young children. Therefore, information on the co-occurrence of mycotoxins and their interactive toxicity is summarized in this paper.

Studies on the Presence of Mycotoxins in Biological Samples: An Overview

Mycotoxins are fungal secondary metabolites with bioaccumulation levels leading to their carry-over into animal fluids, organs, and tissues. As a consequence, mycotoxin determination in biological samples from humans and animals has been reported worldwide. Since most mycotoxins show toxic effects at low concentrations and considering the extremely low levels present in biological samples, the application of reliable detection methods is required. This review summarizes the information regarding the studies involving mycotoxin determination in biological samples over the last 10 years. Relevant data on extraction methodology, detection techniques, sample size, limits of detection, and quantitation are presented herein. Briefly, liquid-liquid extraction followed by LC-MS/MS determination was the most common technique. The most analyzed mycotoxin was ochratoxin A, followed by zearalenone and deoxynivalenol—including their metabolites, enniatins, fumonisins, aflatoxins, T-2 and HT-2 toxins. Moreover, the studies were classified by their purpose, mainly focused on the development of analytical methodologies, mycotoxin biomonitoring, and exposure assessment. The study of tissue distribution, bioaccumulation, carry-over, persistence and transference of mycotoxins, as well as, toxicokinetics and ADME (absorption, distribution, metabolism and excretion) were other proposed goals for biological sample analysis. Finally, an overview of risk assessment was discussed.

Deoxynivalenol Biomarkers in the Urine of UK Vegetarians

Deoxynivalenol (DON) is produced by Fusarium graminearum and is one of the most commonly occurring trichothecenes. Vegetarians are alleged to be a high-risk group for DON exposure due to high intakes of cereals susceptible to the growth of the mycotoxin. This study provides the levels of DON and de-epoxi Deoxynivalenol (DOM-1) in urine analysed by liquid chromatography-mass spectrometry (LC-MS) in UK vegetarians. Over two consecutive days, morning urine samples were collected from 32 vegetarians and 31 UK adult volunteers, and associated food consumption 24 h prior to the sample was recorded. Statistically significant differences between the weight of the UK adults and vegetarians (t = 3.15. df = 61, p ≤ 0.005 two-tailed) were observed. The mean levels of DON in urine for adults on day 1 was 3.05 ng free DON/mg creatinine, and on day 2 was 2.98 ng free DON/mg creatinine. Even though high mean levels were observed, most adults were within the tolerable daily intake. However, for vegetarians, the mean level of urinary DON on day 1 was 6.69 ng free DON/mg creatinine, and on day 2 was 3.42 ng free DON/mg creatinine. These levels equate to up to 32% of vegetarians exceeding recommended tolerable daily intakes (TDI) of exposure (1 µg/kg b.w./day).

Ochratoxin A and its metabolites in urines of German adults-An assessment of variables in biomarker analysis

Ochratoxin A (OTA), a mycotoxin known for its nephrotoxic and carcinogenic properties, is a worldwide occurring contaminant in a variety of food commodities. Biomonitoring (i.e. analysis in biological fluids) can serve to assess human internal exposure from all consumed foods and beverages. We now determined the concentration of OTA and its metabolite ochratoxin alpha (OTα) in plasma and in urine of two male volunteers with different food habits, in order to assess intra-individual temporal fluctuations and inter-individual differences in their biomarker levels. Moreover, the urinary levels of both OTA and OTα were analyzed in a cohort of German adults (23 males, 27 females) on their regular diet. All samples were subjected to an enzymatic hydrolysis of biomarker conjugates prior to clean-up by liquid-liquid extraction and HPLC-FD analysis. The profile in the first individual showed small fluctuations over time: mean levels in plasma were 0.42 and 0.45ng/mL for OTA and OTα, respectively, and in urine means of 0.06ng/mL for both analytes. The other individual had mean levels of 1.64 and 0.20ng/mL for OTA and OTα in plasma, and 0.24 and 2.22ng/mL for these analytes in urine. It is concluded that inter-individual differences in biomarker levels reflect dissimilar dietary exposure and/or disposition of ingested mycotoxin, with an apparently more efficient detoxification of OTA to OTα in the second individual. In the German cohort (n=50), analytes were detected in 100% (OTA: range 0.02-1.82ng/mL mean level 0.21±0.31ng/mL) and 78% (OTα: range 0.01-14.25ng/mL, mean level 1.33±2.63ng/mL) of all urines. Parameters such as gender, age and body mass index did not show a significant association with urine biomarker levels. This study indicates frequent exposure to OTA among German adults. The new results are discussed in the context of biomarker data from other countries and some methodological issues.

Multi-mycotoxin analysis using dried blood spots and dried serum spots

In this study, a rapid multi-mycotoxin approach was developed for biomonitoring and quantification of 27 important mycotoxins and mycotoxin metabolites in human blood samples. HPLC-MS/MS detection was used for the analysis of dried serum spots (DSS) and dried blood spots (DBS). Detection of aflatoxins (AFB₁, AFB₂, AFG₁, AFG₂, AFM₁), trichothecenes (deoxynivalenol, DON; DON-3-glucoronic acid, DON-3-GlcA; T-2; HT-2; and HT-2-4-GlcA), fumonisin B₁ (FB₁), ochratoxins (OTA and its thermal degradation product 2'R-OTA; OTα; 10-hydroxychratoxin A, 10-OH-OTA), citrinin (CIT and its urinary metabolite dihydrocitrinone, DH-CIT), zearalenone and zearalanone (ZEN, ZAN), altenuene (ALT), alternariols (AOH; alternariol monomethyl ether, AME), enniatins (EnA, EnA₁, EnB, EnB₁) and beauvericin (Bea) was validated for two matrices, serum (DSS), and whole blood (DBS). HPLC-MS/MS analysis showed signal suppression as well as signal enhancement due to matrix effects. However, for most analytes LOQs in the lower pg/mL range and excellent recovery rate were achieved using matrix-matched calibration. Besides validation of the method, the analyte stability in DBS and DSS was also investigated. Stability is a main issue for some analytes when the dried samples are stored under common conditions at room temperature. Nevertheless, the developed method was applied to DBS samples of a German cohort (n = 50). Besides positive findings of OTA and 2'R-OTA, all samples were positive for EnB. This methodical study establishes a validated multi-mycotoxin approach for the detection of 27 mycotoxins and metabolites in dried blood/serum spots based on a fast sample preparation followed by sensitive HPLC-MS/MS analysis. Graphical Abstract ᅟ.

Are Treated Celiac Patients at Risk for Mycotoxins? An Italian Case-Study

Urinary biomarkers of mycotoxin exposure were evaluated in a group of celiac patients (n = 55) and in a control group of healthy subjects (n = 50) following their habitual diet. Deoxynivalenol (DON), zearalenone (ZEN), and fumonisin B1 (FB1) were monitored in 105 urinary samples collected from the two groups. Dietary habits were also recorded through compilation of a seven-day weighed dietary diary. Biomarkers of mycotoxin exposure were detected in 21 celiac patients and in 15 control subjects, corresponding to about 34% of total participants. In particular, ZEN was the most detected mycotoxin among all the studied subjects with a total of 19 positive cases. Results did not show a statistically significant difference in mycotoxin exposure between the two groups, and the presence of specific mycotoxins was not related to the intake of any particular food category. Our findings suggest little urgency of specific regulation for gluten free products, although the prevalence of exposure observed in free-living diets of both celiac and healthy subjects underlines the need of a constant surveillance on mycotoxins occurrence at large.

Challenges in risk assessment of multiple mycotoxins in food

Most fungi are able to produce several mycotoxins simultaneously and, consequently, to contaminate a wide variety of foodstuffs. Therefore, the risk of human co-exposure to multiple mycotoxins is real, raising a growing concern about their potential impact on human health. Besides, government and industry regulations are usually based on individual toxicities, and do not take into account the complex dynamics associated with interactions between co-occurring groups of mycotoxins. The present work assembles, for the first time, the challenges posed by the likelihood of human co-exposure to these toxins and the possibility of interactive effects occurring after absorption, towards knowledge generation to support a more accurate human risk assessment. Regarding hazard assessment, a physiologically-based framework is proposed in order to infer the health effects from exposure to multiple mycotoxins in food, including knowledge on the bioaccessibility, toxicokinetics and toxicodynamics of single and combined toxins. The prioritisation of the most relevant mixtures to be tested under experimental conditions that attempt to mimic human exposure and the use of adequate mathematical approaches to evaluate interactions, particularly concerning the combined genotoxicity, were identified as the main challenges for hazard assessment. Regarding exposure assessment, the need of harmonised food consumption data, availability of multianalyte methods for mycotoxin quantification, management of left-censored data, use of probabilistic models and multibiomarker approaches are highlighted, in order to develop a more precise and realistic exposure assessment. To conclude, further studies on hazard and exposure assessment of multiple mycotoxins, using harmonised methodologies, are crucial towards an improvement of data quality and a more reliable and robust risk characterisation, which is central for risk management and, consequently, to prevent mycotoxins-associated adverse effects. A deep understanding of the nature of interactions between multiple mycotoxins will contribute to draw real conclusions on the health impact of human exposure to mycotoxin mixtures.

Multidetection of urinary ochratoxin A, deoxynivalenol and its metabolites: pilot time-course study and risk assessment in Catalonia, Spain

The presence of two main mycotoxins, ochratoxin A (OTA) and deoxynivalenol (DON), is widespread in cereal-based foodstuffs marketed in Europe. The objectives of this study were to develop and validate a multi-detection analytical methodology to simultaneously assess the urinary concentrations of OTA, DON and their metabolites, and to apply this methodology in a preliminary follow-up trial in Catalonia (Spain). Hence, an ultra-performance liquid chromatography with tandem mass spectrometry method was developed to simultaneously assess the urinary levels of OTA, DON, deoxynivalenol-3-glucoside (DON-3-glucoside), deoxynivalenol-3-glucuronide (DON-3-glucuronide), 3-acetyldeoxynivalenol (3-ADON) and de-epoxy-deoxynivalenol (DOM-1). Urine mycotoxins levels and food dietary intake were prospectively monitored in a group of volunteers throughout a restriction period followed by a free-diet period. The proposed multi-detection methodology for urinary OTA and DON metabolites was validated, providing suitable recovery, linearity and precision. The results from the pilot trial showed that urinary OTA, DON and its metabolites were detected in most background samples, displaying moderate reductions after the restriction period and subsequently recovering the background levels. Despite the restriction period, some DON metabolites, such as 3-ADON or DOM-1, were still found in urine samples, placing alternative sources of DON exposure other than the ones considered in the study under suspicion. DON and DON-3-glucuronide were significantly associated with consumption of bread, pasta and pastries, while OTA was only associated with consumption of wine and breakfast cereals. The urinary levels of OTA were significantly correlated with plasmatic levels of OTA and ochratoxin α, supporting the results from the multidetection method in urine. The results also showed that the high exposure to DON could be held throughout the time by the same person, exceeding the tolerable daily intake systematically instead of eventually. The estimates of OTA exposure through urine are largely higher than those obtained with the dietary approach. The background levels found in urine revealed that the exposure to DON and OTA could be of concern for the Catalonian population, thus, further studies applying this biomonitoring methodology in a larger sample of Catalonian population are needed to accurately characterise the human health risks at population level.

Identification of a novel human deoxynivalenol metabolite enhancing proliferation of intestinal and urinary bladder cells

The mycotoxin deoxynivalenol (DON) is an abundant contaminant of cereal based food and a severe issue for global food safety. We report the discovery of DON-3-sulfate as a novel human metabolite and potential new biomarker of DON exposure. The conjugate was detectable in 70% of urine samples obtained from pregnant women in Croatia. For the measurement of urinary metabolites, a highly sensitive and selective LC-MS/MS method was developed and validated. The method was also used to investigate samples from a duplicate diet survey for studying the toxicokinetics of DON-3-sulfate. To get a preliminary insight into the biological relevance of the newly discovered DON-sulfates, in vitroexperiments were performed. In contrast to DON, sulfate conjugates lacked potency to suppress protein translation. However, surprisingly we found that DON-sulfates enhanced proliferation of human HT-29 colon carcinoma cells, primary human colon epithelial cells (HCEC-1CT) and, to some extent, also T24 bladder cancer cells. A proliferative stimulus, especially in tumorigenic cells raises concern on the potential impact of DON-sulfates on consumer health. Thus, a further characterization of their toxicological relevance should be of high priority.

Determination of Exposure to the Alternaria Mycotoxin Tenuazonic Acid and Its Isomer allo-Tenuazonic Acid in a German Population by Stable Isotope Dilution HPLC-MS(3)

The content of the Alternaria toxin tenuazonic acid and its isomer allo-tenuazonic acid was quantitated in urine of a German cohort (n = 48) using a newly developed and successfully validated solid phase extraction based stable isotope dilution HPLC-MS(3) method. Tenuazonic acid was detected in all of the samples and quantifiable in 97.9% of these samples in a range of 0.16-44.4 ng/mL (average = 6.58 ng/mL) or 0.07-63.8 ng/mg creatinine (average = 8.13 ng/mg creatinine). allo-Tenuazonic acid was for the first time detected in human urine (95.8% of the samples positive) and quantitated in 68.8% of the samples in a range of 0.11-5.72 ng/mL (average = 1.25 ng/mL) or 0.08-10.1 ng/mg creatinine (average = 1.52 ng/mg creatinine), representing 3.40-25.0% of the sum of both isomers (average = 12.4%). Food-frequency questionnaires were used to document food consumption of study participants to correlate mycotoxin exposure to nutritional habits. Although no statistically significant correlation between consumption of a specific food and urinary excretion of tenuazonic acid could be determined, a trend regarding elevated intake of cereal products and higher excretion of tenuazonic acid was evident. On the basis of these results, a provisional mean daily intake (PDI) for both tenuazonic acid and allo-tenuazonic acid was calculated, being 0.183 and 0.025 μg/kg body weight, respectively. A combined mean PDI for both isomers amounts to 0.208 μg/kg body weight with the highest individual PDI for one of the participants (1.582 μg/kg body weight) slightly exceeding the threshold of toxicological concern assumed for tenuazonic acid by the European Food Safety Authority of 1.500 μg/kg body weight. This is the first study to investigate the tenuazonic acid content in human urine of a larger sample cohort enabling the calculation of PDIs for tenuazonic acid and allo-tenuazonic acid.

Analysis of aflatoxins in traditional Chinese medicines: Classification of analytical method on the basis of matrix variations

A classification system for analytical methods was developed for the first time to determine the presence of aflatoxins B₁, B₂, G₁ and G₂ in traditional Chinese medicines (TCMs) based on different matrix types using ultra-performance liquid chromatography–tandem mass spectrometry. A useful characteristic of the approach was that the TCMs could be systematically divided into four categories (i.e., volatile oils, proteins, polysaccharides and fatty oils) depending on the matrix types. The approach concluded that different types of TCMs required different optimal sample preparation procedures. Based on the optimized analytical conditions, the limits of detection and quantification, average recoveries and linearity of four aflatoxins were determined and conformed to research limits. Of 22 TCMs samples, 14 samples were contaminated with at least one type aflatoxin at concentrations ranging from 0.2 to 7.5 μg/kg, and the average contents of aflatoxins were significantly different for the different matrix types. Moreover, we found a potential link between the contamination levels of aflatoxins and matrix types. TCMs containing fatty oils were the most susceptible to contamination by aflatoxins and followed by TCMs containing polysaccharides and proteins; TCMs containing abundant amounts of volatile oils were less prone to contamination.

Biodegradation of Mycotoxins: Tales from Known and Unexplored Worlds

Exposure to mycotoxins, secondary metabolites produced by fungi, may infer serious risks for animal and human health and lead to economic losses. Several approaches to reduce these mycotoxins have been investigated such as chemical removal, physical binding, or microbial degradation. This review focuses on the microbial degradation or transformation of mycotoxins, with specific attention to the actual detoxification mechanisms of the mother compound. Furthermore, based on the similarities in chemical structure between groups of mycotoxins and environmentally recalcitrant compounds, known biodegradation pathways and degrading organisms which hold promise for the degradation of mycotoxins are presented.

Biomonitoring of the mycotoxin Zearalenone: current state-of-the art and application to human exposure assessment

Zearalenone (ZEN), a mycotoxin with high estrogenic activity in vitro and in vivo, is a widespread food contaminant that is commonly detected in maize, wheat, barley, sorghum, rye and other grains. Human exposure estimates based on analytical data on ZEN occurrence in various food categories and food consumption data suggest that human exposure to ZEN and modified forms of ZEN may be close to or even exceed the tolerable daily intake (TDI) derived by the European Food Safety Authority (EFSA) for some consumer groups. Considering the inherent uncertainties in estimating dietary intake of ZEN that may lead to an under- or overestimation of ZEN exposure and consequently human risk and current lack of data on vulnerable consumer groups, there is a clear need for more comprehensive and reliable exposure data to refine ZEN risk assessment. Human biomonitoring (HBM) is increasingly being recognized as an efficient and cost-effective way of assessing human exposure to food contaminants, including mycotoxins. Based on animal and (limited) human data on the toxicokinetics of ZEN, it appears that excretion of ZEN and its major metabolites may present suitable biomarkers of ZEN exposure. In view of the limitations of available dietary exposure data on ZEN and its modified forms, the purpose of this review is to provide an overview of recent studies utilizing HBM to monitor and assess human exposure to ZEN. Considerations are given to animal and human toxicokinetic data relevant to HBM, analytical methods, and available HBM data on urinary biomarkers of ZEN exposure in different cohorts.

Mycotoxins: cytotoxicity and biotransformation in animal cells

Mycotoxins are secondary metabolites produced by many microfungi. Hitherto, over 300 mycotoxins with diverse structures have been identified. They contaminate most cereals and feedstuffs, which threaten human and animal health by exerting acute, sub-acute and chronic toxicological effects, with some considered as carcinogens. Many mycotoxins at low concentrations are able to induce the expression of cytochrome P450 and other enzymes implicated in the biotransformation and metabolization of mycotoxins in vivo and in vitro. Mycotoxins and their metabolites elicit different cellular disorders and adverse effects such as oxidative stress, inhibition of translation, DNA damage and apoptosis in host cells, thus causing various kinds of cytotoxicities. In this review, we summarize the biotransformation of mycotoxins in animal cells by CYP450 isoforms and other enzymes, their altered expression under mycotoxin exposure, and recent progress in mycotoxin cytotoxicity in different cell lines. Furthermore, we try to generalize the molecular mechanisms of mycotoxin effects in human and animal cells.

Developments in mycotoxin analysis: an update for 2014-2015

This review summarises developments in the determination of mycotoxins over a period between mid-2014 and mid-2015. In tradition with previous articles of this series, analytical methods to determine aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone are covered in individual sections. Advances in proper sampling strategies are discussed in a dedicated section, as are new methods used to analyse botanicals and spices and newly developed LC-MS based multi-mycotoxin methods. The critical review aims to briefly discuss the most important developments and trends in mycotoxin determination as well as to address shortcomings of current methodologies.

Biomonitoring of Mycotoxins in Urine: Pilot Study in Mill Workers

Contamination of grains with mycotoxins results in a dietary background exposure of the general population. In occupational settings such as during processing of raw materials as in milling, an additional mycotoxin exposure by inhalation is possible. Biomonitoring is an integrative approach to assess human exposure from various sources and by all routes. To investigate possible workplace exposure to mycotoxins, a pilot study was conducted that compared levels of urinary biomarkers in mill workers to those in a control group with dietary mycotoxin intake alone. Workers (n = 17) from three grain mills in North Rhine Westphalia, Germany, provided spot urines during shift; volunteers (n = 13, IfADo staff) with matched age structure served as control group. The mycotoxins selected for biomarker analysis were citrinin (CIT) deoxynivalenol (DON), ochratoxin A (OTA), and zearalenone (ZEN). Immunoaffinity columns (CIT, DON, ZEN) or liquid-liquid extraction (OTA) was employed for urine sample cleanup prior to targeted analysis by liquid chromatography with tandem mass spectrometry (LC-MS/MS) or by high-performance liquid chromatography (HPLC). In addition, mycotoxin metabolites that may be formed in the organism were analyzed, including deepoxy-deoxynivalenol (DOM-1), ochratoxin alpha (OTα), dihydrocitrinone (DH-CIT), and α- and β-zearalenol (α- and β-ZEL), as well as phase II metabolites that were hydrolyzed with β-glucuronidase/arylsulfatase prior to sample cleanup. All analyte concentrations were adjusted for creatinine (crea) content in the spot urine samples. Citrinin, DON, OTA, and ZEN were detected in nearly all urine samples from mill workers and controls. Interestingly, DH-CIT was found at higher mean levels than the parent compound (~0.14 and 0.045 µg/g crea, respectively), suggesting an effective metabolism of CIT in humans. Other metabolites DOM-1, OTα, and α- and β-ZEL were detected less frequently in urine. Deoxynivalenol was detected at the highest concentrations (mean ~6 µg/g crea), followed by OTA (mean ~0.08 µg/g crea); ZEN (mean ~0.03 µg/g crea) and its metabolites appeared in urine at lower levels. Mycotoxin biomarker levels in urine from mill workers and controls were not significantly different. From these results it is concluded that biomarker levels measured in urine samples from the two cohorts reflect mainly dietary mycotoxin exposure. An additional occupational (inhalational) exposure of mill workers, if any, is apparently low at the investigated workplaces.

Blood-Brain Barrier Effects of the Fusarium Mycotoxins Deoxynivalenol, 3 Acetyldeoxynivalenol, and Moniliformin and Their Transfer to the Brain

BACKGROUND

Secondary metabolites produced by Fusarium fungi frequently contaminate food and feed and have adverse effects on human and animal health. Fusarium mycotoxins exhibit a wide structural and biosynthetic diversity leading to different toxicokinetics and toxicodynamics. Several studies investigated the toxicity of mycotoxins, focusing on very specific targets, like the brain. However, it still remains unclear how fast mycotoxins reach the brain and if they impair the integrity of the blood-brain barrier. This study investigated and compared the effects of the Fusarium mycotoxins deoxynivalenol, 3-acetyldeoxynivalenol and moniliformin on the blood-brain barrier. Furthermore, the transfer properties to the brain were analyzed, which are required for risk assessment, including potential neurotoxic effects.

METHODS

Primary porcine brain capillary endothelial cells were cultivated to study the effects of the examined mycotoxins on the blood-brain barrier in vitro. The barrier integrity was monitored by cellular impedance spectroscopy and 14C radiolabeled sucrose permeability measurements. The distribution of the applied toxins between blood and brain compartments of the cell monolayer was analyzed by high performance liquid chromatography-mass spectrometry to calculate transfer rates and permeability coefficients.

RESULTS

Deoxynivalenol reduced the barrier integrity and caused cytotoxic effects at 10 μM concentrations. Slight alterations of the barrier integrity were also detected for 3-acetyldeoxynivalenol. The latter was transferred very quickly across the barrier and additionally cleaved to deoxynivalenol. The transfer of deoxynivalenol and moniliformin was slower, but clearly exceeded the permeability of the negative control. None of the compounds was enriched in one of the compartments, indicating that no efflux transport protein is involved in their transport.

Human biomonitoring of multiple mycotoxins in the Belgian population: Results of the BIOMYCO study

Mycotoxins are important food contaminants responsible for health effects such as cancer, nephrotoxicity, hepatotoxicity or immunosuppression. The assessment of mycotoxin exposure is often based on calculations combining mycotoxin occurrence data in food with population data on food consumption. Because of limitations inherent to that approach, the direct measurement of biomarkers of exposure in biological fluids has been proposed as a suitable alternative to perform an accurate mycotoxin exposure assessment at individual level. For this reason, the BIOMYCO study was designed to assess mycotoxin exposure in Belgian adults and children using urinary biomarkers of exposure. Morning urine was gathered in a representative part of the Belgian population according to a standardised study protocol, whereby 155 children (3-12 years old) and 239 adults (19-65 years old) were selected based on random cluster sampling. These urine samples were analysed for the presence of 33 potential biomarkers with focus on aflatoxins, citrinin (CIT), fumonisins, trichothecenes, ochratoxin A (OTA), zearalenone and their metabolites using two validated LC-MS/MS methods. Nine out of the 33 analysed mycotoxins were detected whereby deoxynivalenol (DON), OTA, CIT and their metabolites were the most frequently detected. Deoxynivalenol-15-glucuronide was the main urinary DON biomarker and was found in all urine samples in the ng/mL range. Furthermore deoxynivalenol-3-glucuronide was quantified in 91% of the urine samples collected from children and in 77% of the samples collected from adults. Deoxynivalenol was detected in 70% and 37% of the samples of children and adults respectively. For the first time deepoxy-deoxynivalenol-glucuronide was detected in children's urine (17%). In the samples collected by adults, the prevalence was 22%. Whereas all these mycotoxins contaminated the urine samples in the ng/mL range, CIT and OTA were present in much lower concentrations (pg/mL). OTA contaminated 51% and 35% of the samples collected by children and adults respectively. CIT and its metabolite were present in 72% and 6% of children's urine, whereas they contaminated 59% and 12% of adult's urine. Finally, α-zearalenol and β-zearalenol-14-glucuronide were found in respectively one and two samples from adults. The exposure to DON, OTA and CIT was compared between subgroups and urinary mycotoxin concentrations differed significantly among age and gender. Based on the urinary levels, the daily intake of DON and OTA was estimated and evaluated whereby, depending on the used method, 16-69% of the population possibly exceeded the tolerable daily intake for DON and 1% for OTA. The BIOMYCO study is the first study whereby a multi-toxin approach was applied for mycotoxin exposure assessment in adults and children on a large-scale. Moreover, it is the first study that described the exposure to an elaborated set of mycotoxins in the Belgian population. Biomarker analysis showed a clear exposure of a broad segment of the Belgian population to DON, OTA and CIT. The risk assessment based on these data indicates a potential concern for a number of individuals whereby young children need special attention because of the relatively higher food intake per kg body weight.

Deoxynivalenol Exposure Assessment for Pregnant Women in Bangladesh

The trichothecene mycotoxin deoxynivalenol (DON) is a contaminant of crops worldwide and known to cause adverse health effects in exposed animals and humans. A small survey reported the presence of DON in maize samples in Bangladesh, but these data are insufficient to assess human exposure, and also, biomonitoring data are still scarce. The present study applied biomarker analysis to investigate the DON exposure of pregnant women in Bangladesh. Urine samples were collected from pregnant women living in a rural (n = 32) and in a suburban (n = 22) area of the country. Urines were subjected to enzymatic hydrolysis of glucuronic acid conjugates and to immunoaffinity column clean-up prior to LC-MS/MS analysis of DON and its de-epoxy metabolite DOM-1. The limits of detection (LOD) for DON and DOM-1 in urine were 0.16 ng/mL and 0.10 ng/mL, respectively. DOM-1 was not detected in any of the urines, whilst DON was detectable in 52% of the samples at levels ranging from 0.18–7.16 ng/mL and a mean DON concentration of 0.86 ± 1.57 ng/mL or 2.14 ± 4.74 ng/mg creatinine. A significant difference in mean urinary DON levels was found between the rural (0.47 ± 0.73 ng/mL) and suburban (1.44 ± 2.20 ng/mL) cohort, which may be related to different food habits in the two cohorts. Analysis of food consumption data for the participants did not show significant correlations between their intake of typical staple foods and DON levels in urine. The biomarker concentrations found and published urinary excretion rates for DON were used to estimate daily mycotoxin intake in the cohort: the mean DON intake was 0.05 µg/kg b.w., and the maximum intake was 0.46 µg/kg b.w., values lower than the tolerable daily intake of 1 µg/kg b.w. These first results indicate a low dietary exposure of pregnant women in Bangladesh to DON. Nonetheless, further biomonitoring studies in children and in adult cohorts from other parts of the country are of interest to gain more insight into DON exposure in the population of Bangladesh.

Biomonitoring using dried blood spots: detection of ochratoxin A and its degradation product 2'R-ochratoxin A in blood from coffee drinkers

SCOPE

In this study, human exposure to the mycotoxin ochratoxin A (OTA) and its thermal degradation product 2'R-ochratoxin A (2'R-OTA, previously named as 14R-Ochratoxin A [22]) through coffee consumption was assessed. LC-MS/MS and the dried blood spot (DBS) technique were used for the analysis of blood samples from coffee and noncoffee drinkers (n = 50), and food frequency questionnaires were used to document coffee consumption.

METHODS AND RESULTS

For the detection of OTA and 2'R-OTA in blood, a new sensitive and efficient sample preparation method based on DBS was established and validated. Using this technique 2'R-OTA was for the first time detected in biological samples. Comparison between coffee drinkers and noncoffee drinkers showed for the first time that 2'R-OTA was only present in blood from the first group while OTA could be found in both groups in a mean concentration of 0.21 μg/L. 2'R-OTA mean concentration was 0.11 μg/L with a maximum concentration of 0.414 μg/L. Thus, in average 2'R-OTA was approx. half the concentration of OTA but in some cases even exceeded OTA levels. No correlation between the amounts of coffee consumption and OTA or 2'R-OTA levels was observed.

CONCLUSION

The results of this study revealed for the first time a high exposure of coffee consumers to 2'R-OTA, a compound formed from OTA during coffee roasting. Since little information is available regarding toxicity and possible carcinogenicity of this compound, further OTA monitoring in blood including 2'R-OTA is advisable.

A comparative study of the human urinary mycotoxin excretion patterns in Bangladesh, Germany, and Haiti using a rapid and sensitive LC-MS/MS approach

An improved "dilute and shoot" LC-MS/MS multibiomarker approach was used to monitor urinary excretion of 23 mycotoxins and their metabolites in human populations from Asia (Bangladesh), Europe (Germany), and the Caribbean region (Haiti). Deoxynivalenol (DON), deoxynivalenol-3-glucuronide (DON-3-GlcA), T-2-toxin (T-2), HT-2-toxin (HT-2), HT-2-toxin-4-glucuronide (HT-2-4-GlcA), fumonisin B1 (FB1), aflatoxins (AFB1, AFB2, AFG1, AFG2, AFM1), zearalenone (ZEA), zearalanone (ZAN), their urinary metabolites α-zearalanol (α-ZEL) and β-zearalanol (β-ZEL), and corresponding 14-O-glucuronic acid conjugates (ZEA-14-GlcA, ZAN-14-GlcA, β-ZEL, α/β-ZEL-14-GlcA), ochratoxin A (OTA), and ochratoxin alpha (OTα) as well as enniatin B (EnB) and dihydrocitrinone (DH-CIT) were among these compounds. Eight urinary mycotoxin biomarkers were detected (AFM1, DH-CIT, DON, DON-GLcA, EnB, FB1, OTA, and α-ZEL). DON and DON-GlcA were exclusively detected in urines from Germany and Haiti whereas urinary OTA and DH-CIT concentrations were significantly higher in Bangladeshi samples. AFM1 was present in samples from Bangladesh and Haiti only. Exposure was estimated by the calculation of probable daily intakes (PDI), and estimates suggested occasional instances of toxin intakes that exceed established tolerable daily intakes (TDI). The detection of individual mycotoxin exposure by biomarker-based approaches is a meaningful addition to the classical monitoring of the mycotoxin content of the food supply.

Deoxynivalenol inhibits the expression by goblet cells of intestinal mucins through a PKR and MAP kinase dependent repression of the resistin-like molecule β

SCOPE

The food-associated mycotoxin deoxynivalenol (DON) is known to affect intestinal functions. However, its effect on intestinal mucus is poorly characterized.

METHODS AND RESULTS

We analyzed the effects of DON on human goblet cells (HT29-16E cells) and porcine intestinal explants. Results showed that subtoxic doses of DON (as low as 1 μM) decreased mucin (MUC) production. qPCR analysis demonstrated that this inhibition was due to a specific decrease in the level of mRNA encoding for the intestinal membrane-associated (MUC1) and the secreted MUCs (MUC2, MUC3). Mechanistic studies demonstrated that DON effect relied on the activation of the protein kinase R and the mitogen-activated protein kinase p38 ultimately leading to the inhibition of the expression of resistin-like molecule beta, a known positive regulator of MUC expression.

CONCLUSION

Taken together, our results show that at low doses found in food and feed, DON is able to affect the expression and production of MUCs by human and animal goblet cells. Due to the important role of MUCs in the barrier function and in the interaction of commensal bacteria with the host, such effect could explain the observed modifications in the microbial diversity and the increased susceptibility to enteric infection following exposure to DON.