Survey on ergot alkaloids in cereals intended for human consumption and animal feeding

Correlation patterns prevalence, and co-occurrence of ergot alkaloids in cool-season adapted cereal grains revealed with molecular spectroscopy and LC-MS/MS equipped HPLC system

It is necessary to obtain more recent data on the prevalence and co-occurrence of mycotoxins in feed and food to minimize risks. This study examined the recent presence, co-occurrence, and correlation patterns of six major ergot alkaloids (EAs; i.e. ergocornine, ergocristine, ergocryptine, ergometrine, ergosine, and ergotamine) in cool-season adapted barley (n = 57) and wheat (n = 80) submitted by livestock producers and industries for testing ergot alkaloids/mycotoxins by liquid chromatography - tandem mass spectrometry method. Overall, 91% industry-submitted barley samples and 84% industry-submitted wheat samples tested positive for at least one ergot alkaloid and 33% industry-submitted barley and 38% industry-submitted wheat samples were found to be co-contaminated with all six major EAs. The content of total EAs in 9 industry-submitted barley (16%) and 18 industry-submitted wheat (23%) samples exceeded the recommended maximum allowable level for lactating or pregnant animals (250 ppb). All the barley and wheat samples that contained detectable ergosine were found to co-occur with other EAs. Overall, the content of individual EAs was positively correlated with each other and strong correlations (r > 0.8, P < 0.01) were detected between the content of individual EAs and total EAs. These results implied that the industry and producers submitted cool-season adapted barley and wheat samples contaminated with a single EA is likely to contain high levels of other major EAs. The patterns of individual EAs in this study were distinct from previous studies that focus on samples from European countries. Ergocristine was remained as the predominant EAs in the industry-submitted cool-season adapted barley and wheat samples at levels up to 9438.8 and 12416.2 ppb, respectively. While the mean contents of ergosine were the lowest (68.5 and 50.6 ppb for the industry-submitted cool-season adapted barley and wheat samples, respectively). The high prevalence and co-occurrence of EAs indicated that ergot contamination is still posing a significant threat to food and feed industry and more research is expected to reduce the contamination level and explore the toxicological significance of various co-occurrence profiles. A full scale of investigation for all barley and wheat samples is needed to obtain a full picture of mycotoxin contamination.

Simultaneous quantification of ergot and tropane alkaloids in bread in the Netherlands by LC-MS/MS

Atropine and scopolamine are tropane alkaloids (TAs), which are regulated for cereal-based foods for children in the EU. For ergot alkaloids (EAs) in cereals and cereal-based food harmonised legislation is not yet established. A fast and straightforward method, which employs extraction by acidified water/methanol followed by ultra-filtration prior to analysis by LC-MS/MS, was validated in bread for 20 EAs and six TAs. LOQs for individual alkaloids ranged from 0.3 to 1.2 µg kg^-1, while recoveries ranged from 65% to 94% and repeatability from 3.4% to 17%. A survey was conducted in the Netherlands on 40 retail samples of bread (wheat, rye, wheat-rye, multi-grain) collected in 2014 and 2018. TAs, including atropine and scopolamine, were not detected. Eighteen different EAs were detected and total levels varied between <LOQ and 335 µg kg^-1. Since EAs were detected in a wide concentration range, it is recommended to monitor their occurrence in bread more regularly.

Human and animal dietary exposure to ergot alkaloids

The ergot alkaloids (EAs) are mycotoxins produced by several species of fungi in the genus Claviceps. In Europe, Claviceps purpurea is the most widespread species and it commonly affects cereals such as rye, wheat, triticale, barley, millets and oats. Food and feed samples used to estimate human and animal dietary exposure were analysed for the 12 main C. purpurea EAs: ergometrine, ergosine, ergocornine, ergotamine, ergocristine, ergocryptine (α‐ and β‐isomers) and their corresponding –inine (S)‐epimers. The highest levels of EAs were reported in rye and rye‐containing commodities. In humans, mean chronic dietary exposure was highest in ‘Toddlers’ and ‘Other children’ with maximum UB estimates of 0.47 and 0.46 μg/kg bw per day, respectively. The 95th percentile exposure was highest in ‘Toddlers’ with a maximum UB estimate of 0.86 μg/kg bw per day. UB estimations were on average fourfold higher than LB estimations. Average acute exposure (MB estimations) ranged from 0.02 μg/kg bw per day in ‘Infants’ up to 0.32 μg/kg bw per day estimated in ‘Other children’. For the 95th percentile acute exposure, the highest estimate was for a dietary survey within the age class ‘Other children’ (0.98 μg/kg bw per day). Dietary exposure estimates for animals, assuming a mean concentration scenario, varied between 0.31–0.46 μg/kg bw per day in beef cattle and 6.82–8.07 μg/kg bw per day (LB–UB) in piglets, while exposure estimates assuming a high concentration scenario (95th percentile) varied between 1.43–1.45 μg/kg bw per day and 16.38–16.61 μg/kg bw per day (LB–UB) in the same species. A statistically significant linear relationship between the content of sclerotia and the levels of EAs quantified was observed in different crops (barley, oats, rye, triticale and wheat grains). However, the absence of sclerotia cannot exclude the presence of EAs as samples with no sclerotia identified showed measurable levels of EAs (‘false negatives’).

Occurrence of ergot alkaloids in wheat from Albania

The occurrence of ergot alkaloids in wheat harvested in Albania was investigated. A total of 71 samples of winter wheat collected in 2014 and 2015 were analysed for the 12 most important ergot alkaloids using liquid chromatography-tandem mass spectrometry. In the harvesting year 2014, 48.6% of samples were contaminated with ergot alkaloids, whereas in 2015 only 19.4% of samples were contaminated. In 2014, the concentrations of total ergot alkaloids ranged from 17.3 to 975.4 μg kg^-1, and in 2015 they ranged from 10.3 to 390.5 μg kg^-1. The samples contained from one to nine ergot alkaloids. The most frequent were ergometrine, ergosine and ergocristine, and the least frequent were ergocryptine, ergocryptinine and ergocorninine.

An integrated targeted and untargeted approach for the analysis of ergot alkaloids in cereals using UHPLC – hybrid quadrupole time-of-flight mass spectrometry

An ultra-high performance liquid chromatography hybrid quadrupole – time of flight (Q-TOF) mass spectrometry (MS) method is described for the simultaneous quantitative determination of common ergot alkaloids and the screening, detection and identification of unexpected (less studied or novel) members of this class of toxic fungal secondary metabolites. The employed analytical strategy involves an untargeted data acquisition (consisting of full scan TOF MS survey and information dependent acquisition MS/MS scans) and the processing of data using both targeted and untargeted approaches. Method performance characteristics for the quantitative analysis of 6 common ergot alkaloids i.e. ergometrine, ergosine, ergotamine, ergocornine, ergocristine, ergokryptine and their corresponding epimers in rye were comparable to those previously reported for triple-quadrupole (QqQ) MS/MS. The method limits of quantification (LOQ) were in the range from 3 to 19 μg/kg, and good linearity was observed for the different ergot alkaloids in the range from LOQ to 1000 μg/kg. Furthermore, the method demonstrated good precision (relative standard deviations at 50 μg/kg not higher than 14.6 and 16.2% for the intra-day and inter-day precision, respectively), and the trueness values at different concentration levels were all between 89 and 115%. The method was applied for the analysis of a set of 17 rye samples and demonstrated the presence of these ergot alkaloids in the range from <LOQ to 2,811 μg/kg. Further mining of the same data based on a ‘non-targeted peak finding’ algorithm and the use of full MS and MS/MS accurate mass data allowed the detection and identification of 19 ergot alkaloids that are commonly not included in most analytical methods using QqQ instruments. Some of these alkaloids are reported for the first time in naturally contaminated samples.

Pattern and distribution of ergot alkaloids in cereals and cereal products from European countries

This paper reports on the occurrence of ergot alkaloids in cereals and cereal products in Europe. It includes occurrence data our group previously submitted to the European Food Safety Authority and new data we gathered afterwards. A total of 1,065 samples of cereals and cereal products intended for human consumption and animal feeding were analysed by liquid chromatography-tandem mass spectrometry for the presence of ergot alkaloids. The sample set included rye-, wheat- and multigrain-based food as well as rye-, wheat- and triticale-based feed. The study revealed that 59% of the analysed food and feed samples were contaminated with ergot alkaloids to some extent. In 55% of the samples, the levels of the -ine isomers were above the limit of quantification (LOQ), while contamination with the -inine isomers was found in 51% of the samples. The median values for the main ergot alkaloids (-ine forms) and the epimers (-inine forms) were 1 and 2 μg/kg, respectively. Ergot alkaloids were present in 84% of rye food, 67% of wheat food, 48% of multigrain food, 52% of rye feed, 27% of wheat feed, and 44% of triticale feed at total alkaloid levels ranging from ≤1 (LOQ) to 12,340 μg/kg. Though the highest frequencies of contamination were observed for food samples, the feed samples, in particular Swiss rye feed, accounted for the highest levels of ergot alkaloids. The frequencies and levels of contamination were significantly lower in organic samples compared to conventional samples. Maximum levels of individual ergot alkaloids up to 3,270 μg/kg (for ergotamine) were observed. Overall, ergosine, ergokryptine and ergocristine were the frequently occurring ergot alkaloids. The co-occurrence of all six ergot alkaloids was noted in 35% of the positive samples. Occurrence of a single ergot alkaloid was mainly observed for ergometrine.

Novel solid-phase extraction for epimer-specific quantitation of ergot alkaloids in rye flour and wheat germ oil

Ergot alkaloids and their epimer-specific determination have gained increasing importance for food safety. A solid-phase extraction and cleanup method based on sodium-neutralized strong cation exchange (Na(+)-SCX) was developed to quantitate 12 priority ergot alkaloids in rye flour and wheat germ oil by HPLC fluorescence analysis. Sample preparation is achieved by omitting acidic and alkaline conditions enabling minimized epimerization, which is necessary to determine ergot alkaloids according to their natural distribution in foods. Ergot alkaloids are eluted from SCX-column by forming ion pairs using a sodium hexanesulfonate containing solution which prevents epimerization for at least 96 h. Method validation yielded recoveries of 80-120% (rye flour) and 71-96% (wheat germ oil) with a maximum limit of quantitation (LOQ) of 2.0 μg kg(-1) per ergot alkaloid for both matrices. The applicability of the developed method was demonstrated by analyzing 16 samples from German retail markets: 9 rye flours (max 178 ± 5 μg kg(-1)) and, reported for the first time, 7 wheat germ oils (max 56.8 ± 2.7 μg kg(-1)) expressed as the sum of 12 ergot alkaloids.

Rapid and sensitive LC-MS/MS determination of ergot alkaloids in buffered solutions: application to in vitro testing of a clay-based mycotoxin binder

A rapid liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for the determination of ergot alkaloids in buffered solutions from in vitro studies. The method implied a liquid-liquid extraction of the analytes under alkaline conditions prior to LC-MS/MS analysis and resulted in good recovery (91-123%) of the six ergot alkaloids defined by the European Food Safety Authority as most important, namely ergometrine, ergosine, ergotamine, ergocornine, ergokryptine and ergocristine, as well as their corresponding epimers. The method also proved to be sensitive, repeatable, linear, accurate and robust. Furthermore, the method was applied to evaluate the in vitro binding efficacy of a clay-based mycotoxin binder towards ergometrine, ergosine and ergocornine, through a design encompassing pH 3.0 and 6.8 to mimic the digestive tract. The binder demonstrated binding efficacy of 24, 93 and 97%, respectively, for these ergot alkaloids.