Fusarium Mycotoxins Stability during the Malting and Brewing Processes

Monitoring Fusarium toxins from barley to malt: Targeted inoculation with Fusarium culmorum

Molds of the genus Fusarium infect nearly all types of grain, causing significant yield and quality losses. Many species of this genus produce mycotoxins, which pose significant risks to human and animal health. In beer production, the complex interaction between primary fungal metabolites and secondarily modified mycotoxins in barley, malt, and beer complicates the situation, highlighting the need for effective analytical methods to quickly and accurately monitor these toxins. We developed and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to simultaneously analyze 14 Fusarium toxins, including modified forms (deoxynivalenol (DON), DON-3-glucoside, 3-acetyl-DON, 15-acetyl-DON, nivalenol, fusarenone X, HT-2 toxin, T-2 toxin, the enniatins A, A1, B, B1, beauvericin, and zearalenone) in barley and throughout the malting process. Stable isotope dilution assays (SIDAs) and matrix-matched calibration were used for quantification. A micro-malting setup was established to produce Fusarium-contaminated barley malt under reproducible conditions using targeted inoculation with F. culmorum. Mycotoxins were quantified throughout the malting process and compared to the content of fungal DNA. Further, the impact of various malting parameters was investigated, thus revealing that different malting scenarios exhibited different toxin enrichment patterns. We demonstrated that mycotoxin concentration and the ratio of DON to DON-3-glucoside changed throughout the malting processes, depending on fungal spore concentrations, germination temperature, and malting temperature. The study highlights the complexity of mycotoxin dynamics in malt production and the importance of optimized processing conditions to minimize toxin levels in final malt products.

Mycotoxins in brewing and malting: is every sample contaminated with mycotoxins?

Mycotoxins are secondary metabolites of fungi and represent a serious problem for human health. Due to growing interest, various aspects have been widely studied by scientific groups. One of these aspects relates to the food industry and associated beer production. Mycotoxins can be present in the basic raw materials for beer production as well as in brewed beer. Problematic mycotoxins that pose a serious risk of toxicity are aflatoxins especially aflatoxin B1 (AFB1), fumonisins (FBs), and zearalenone (ZEN) and its metabolites, deoxynivalenol (DON) including its acetylated forms and also the modified form deoxynivalenol-3-glucoside (DON-3G), T-2 toxin, HT-2 toxin, and ochratoxin A. The Research Institute of Brewing and Malting has been dealing with the issue of mycotoxins since 2008. This study describes the analysis of the above mycotoxins during 2020-2024 in barley (n = 775), malt (n = 751), and commercially available beers (n = 522) using QuEChERS, immunoaffinity columns, and UPLC-MS/MS. The results showed positive samples of mycotoxins in brewing and malting matrices at the level of micrograms per kilogram (barley, malt) and nanograms per liter for beer. Therefore, it is a residual concentration and the accurate quantitative determination of mycotoxins, correct interpretation of the results in connection with toxicological values, and the maximum permissible levels of mycotoxins play a key role in global food safety and consumer protection.

Integrative LC-MS and GC-MS metabolic profiling unveils dynamic changes during barley malting

Malting involves complex biochemical transformations affecting sensory and quality attributes. Despite extensive research on storage carbohydrates and proteins in malting, the lack of a detailed metabolic understanding of this process limits our ability to assess and enhance malt quality. This study employed untargeted GC-MS and LC-MS metabolite profiling across six malting timepoints to identify 4980 known metabolites, 82 % of which exhibited significant changes during the malting process. Here we identified stage-dependent metabolic shifts and dynamic chemical classes and pathways between each studied stage. These results can guide the fine-tuning of malting conditions to improve malt quality for beer production and other malt-based applications. Additionally, metabolites with antimicrobial properties were identified, underscoring the interplay between barley and microbial metabolic processes during malting. Further research into these microbial metabolites and cognate microbes may lead to novel malting assessment traits for high-quality and safe malted barley.

Potential for the Bio-Detoxification of the Mycotoxins Enniatin B and Deoxynivalenol by Lactic Acid Bacteria and Bacillus spp

Mycotoxins, toxic compounds produced by fungi, pose significant risks to food safety and human health. This study investigates the bio-detoxification potential of 238 strains of lactic acid bacteria (LAB) and Bacillus spp., previously isolated from cereals (including mycotoxin-contaminated grains), against the emerging mycotoxin, enniatin B (ENB), and the prevalent mycotoxin, deoxynivalenol (DON). Out of the tested strains, 26 demonstrated notable mycotoxin reduction capabilities, including 2 Bacillus pumilus and 24 Bacillus licheniformis strains. B. licheniformis strains MA572, MA695, MA696, TR174a, TR284, TR363, and TR466a degraded ENB to levels below the detection limit, and six strains reduced DON by 30-35%; B. licheniformis TR251b and TR374 showed the highest DON reduction with 35.7%. The most promising strains for bio-detoxification were B. licheniformis TR284, which achieved a 100% reduction in ENB and a 28.6% reduction in DON and B. licheniformis TR388 with a 97.5% reduction in ENB and a 31.9% reduction in DON. None of the tested LAB strains significantly reduced either mycotoxin. These findings highlight the promising potential of B. licheniformis strains in bio-detoxifying mycotoxin-contaminated cereal products. Further research into the underlying detoxification mechanisms and safety aspects is essential to develop effective bio-detoxification strategies for enhancing food safety.

Determination of mycotoxins and their dietary exposure assessment in pale lager beers using immunoaffinity columns and UPLC-MS/MS

The use of contaminated raw materials can lead to the transfer of mycotoxins into the final product, including beer. This study describes the use of the commercially available immunoaffinity column 11⁺Myco MS-PREP^® and UPLC-MS/MS for the determination of mycotoxins in pale lager-type beers brewed in Czech Republic and other European countries. The additional aim of the work was to develop, optimize and validate this analytical method. Validation parameters such as linearity, limit of detection (LOD), limit of quantification (LOQ), precision and accuracy were tested. The calibration curves were linear with correlation coefficients (R² > 0.99) for all mycotoxins under investigation. The LOD ranged from 0.1 to 50 ng/L and LOQ from 0.4 to 167 ng/L. Recoveries of the selected analytes ranged from 72.2 to 101.1%, and the relative standard deviation under conditions repeatability (RSDr) did not exceed 16.3% for any mycotoxin. The validated procedure was successfully applied for the analysis of mycotoxins in a total of 89 beers from the retail network. The results were also processed using advanced chemometric techniques and compared with similar published studies. The toxicological impact was taken into account.

Mycotoxins’ Prevalence in Food Industry By-Products: A Systematic Review

The recovery of biomolecules from food industry by-products is of major relevance for a circular economy strategy. However, by-products’ contamination with mycotoxins represents a drawback for their reliable valorization for food and feed, hampering their application range, especially as food ingredients. Mycotoxin contamination occurs even in dried matrices. There is a need for the implantation of monitoring programs, even for by-products used as animal feed, since very high levels can be reached. This systematic review aims to identify the food by-products that have been studied from 2000 until 2022 (22 years) concerning mycotoxins’ contamination, distribution, and prevalence in those by-products. PRISMA (“Preferred Reporting Items for Systematic Reviews and MetaAnalyses”) protocol was performed via two databases (PubMed and SCOPUS) to summarize the research findings. After the screening and selection process, the full texts of eligible articles (32 studies) were evaluated, and data from 16 studies were considered. A total of 6 by-products were assessed concerning mycotoxin content; these include distiller dried grain with solubles, brewer’s spent grain, brewer’s spent yeast, cocoa shell, grape pomace, and sugar beet pulp. Frequent mycotoxins in these by-products are AFB1, OTA, FBs, DON, and ZEA. The high prevalence of contaminated samples, which surpasses the limits established for human consumption, thus limiting their valorization as ingredients in the food industry. Co-contamination is frequent, which can cause synergistic interactions and amplify their toxicity.

Mixtures of mycotoxins, phytoestrogens and pesticides co-occurring in wet spent brewery grains (BSG) intended for dairy cattle feeding in Austria

Spent brewery grains (BSG) are the main by-product of beer production and are incorporated in rations of food-delivering animals, mainly dairy cows. Like other agricultural commodities, BSG can be contaminated by a broad spectrum of natural and synthetic undesirable substances, which can be hazardous to animal and human health as well as to the environment. The co-occurrence of mycotoxins, phytoestrogens, other fungal and plant secondary metabolites, along with pesticides, was investigated in 21 BSG samples collected in dairy farms in Austria. For this purpose, a validated multi-metabolite liquid chromatography/electrospray ionisation tandem mass spectrometry (LC/ESI-MS/MS) was employed. Metabolites derived from Fusarium, Aspergillus, Alternaria and pesticide residues, were ubiquitous in the samples. Zearalenone (ZEN), T-2 and HT-2 toxins were the only regulated mycotoxin detected, albeit at concentrations below the European guidance values for animal feeds. Ergot alkaloids, Penicillium-derived metabolites, and phytoestrogens had occurrence rates of 90, 48 and 29%, respectively. Penicillium metabolites presented the highest levels among the fungal compounds, indicating contamination during storage. Aflatoxins (AFs), ochratoxins and deoxynivalenol (DON) were not detected. Out of the 16 detected pesticides, two fungicides, ametoctradin (9.5%) and mandipropamid (14.3%) revealed concentrations exceeding their respective maximum residue level (MRL) (0.01 mg kg^-1) for barley in two samples. Although based on European guidance and MRL values the levels of the detected compounds probably do not pose acute risks for cattle, the impact of the long-time exposure to such mixtures of natural and synthetic toxicants on animal health and food safety are unknown and must be elucidated.

Zearalenone and Its Masked Forms in Cereals and Cereal-Derived Products: A Review of the Characteristics, Incidence, and Fate in Food Processing

Zearalenone (ZEA) is known as a Fusarium-produced mycotoxin, representing a risk to cereal food safety with repercussions for economies and worldwide trade. Recent studies have reported the co-occurrence of ZEA and masked ZEA in a variety of cereals and cereal-based products, which may exert adverse effects on public health due to additive/synergistic interactions. However, the co-contamination of ZEA and masked ZEA has received little attention. In order to minimize the threats of co-contamination by ZEA and masked ZEA, it is necessary to recognize the occurrence and formation of ZEA and masked ZEA. This review focuses on the characteristics, incidence, and detection of ZEA and its masked forms. Additionally, the fate of ZEA and masked ZEA during the processing of bread, cake, biscuits, pasta, and beer, as well as the ZEA limit, are discussed. The incidence of masked ZEA is lower than that of ZEA, and the mean level of masked ZEA varies greatly between cereal samples. Published data showed a considerable degree of heterogeneity in the destiny of ZEA during cereal-based food processing, mostly as a result of the varying contamination levels and complicated food processing methods. Knowledge of the fate of ZEA and masked ZEA throughout cereal-based food processing may reduce the likelihood of severe detrimental market and trade ramifications. The revision of legislative limits of masked ZEA may become a challenge in the future.

Impact of the Inoculation Method of Geotrichum candidum, Used as Biocontrol Agent, on T-2 Toxin Produced by Fusarium sporotrichioides and F. langsethiae during the Malting Process

In malt production, steeping and germination steps offer favorable environmental conditions for fungal proliferation when barley is already contaminated by Fusarium species, T-2 toxin producers. However, the use of G. candidum as a biocontrol agent can prevent this proliferation. Indeed, in previous work, a correlation between phenyllactic acid (PLA) production by G. candidum and the reduction in Fusarium sporotrichioides and F. langsethiae growth and T-2 toxin concentration was demonstrated. In the present study, to improve the efficiency of G. candidum, the effects of the inoculum concentration and the inoculation method of G. candidum on PLA and T-2 toxin concentrations were evaluated. First, co-culture experiments with Fusarium species and G. candidum were conducted in a liquid synthetic medium. The results showed that inoculation of G. candidum in the freeze-dried form at 0.4 g/L allowed the production of PLA from the second day of incubation associated with a reduction in T-2 toxin concentration of 82% and 69% produced by F. sporotrichioides and F. langsethiae, respectively. Moreover, the activated form of G. candidum at 0.4 g/L enhanced PLA concentration leading to better T-2 toxin reduction. Second, experiments were conducted on artificially infected barley kernels with both Fusarium species under conditions mimicking the malting step. As for co-culture experiments, the use of the activated form of G. candidum was established as the best condition for T-2 toxin concentration reduction for a 3 day malting period.

Free and conjugated Alternaria and Fusarium mycotoxins during Pilsner malt production and double-mash brewing

Malting and brewing have previously been demonstrated to be risky procedures in terms of mycotoxins contamination. The goal of the study was to describe the fate of less investigated Fusarium and Alternaria mycotoxins, together with their conjugates, during these processes. The Pilsner malt producing process, together with double-mash brewing, were performed in a pilot-scale malting and brewery plants to simulate production of lager - the most popular type of central European beer. In addition, changes in temperature during barley germination were investigated to assess the influence of this critical step. QuEChERS-like extraction followed by UHPLC-HRMS/MS were utilized to quantify the mass balance of 13 mycotoxins and four of their conjugates. The results confirmed germination as the most determining malting step, followed by mashing of malt during brewing. Occurrence of type A trichothecenes, Alternaria mycotoxins and their conjugates in the final beer product indicates the need to take mitigation measures.

A worldwide systematic review, meta-analysis, and health risk assessment study of mycotoxins in beers

Mycotoxins, including aflatoxins (AFs), ochratoxin A (OTA), deoxynivalenol (DON), fumonisins (FBs), and zearalenone (ZEN), have been reported as beer contaminants. This systematic review and meta-analysis provide the prevalence and concentration of mycotoxins in beers and their worldwide distribution. Mycotoxin's exposure and cancer risk through beer consumption were determined. The overall pooled prevalence of mycotoxins in beers was 31% (95% confidence interval [CI] = 28%-35%; I²  = 90%, p = .00). The most prevalent mycotoxins in beers were DON and its derivatives (53%), OTA (52%), FBs (47%), followed by AFs (12%). Iran (99%), Hungary (95%), Denmark (92%), Armenia (83%), and Cyprus (83%) had the highest mycotoxin prevalence in beers. The global mycotoxins average concentration in beers was 12.52 μg/L (95% CI = 10.70-14.75 μg/L; I²  = 100%, p = .00). DON and its derivatives showed the highest concentration (26.91 μg/L), followed by FBs (23.19 μg/L), ZEN and its derivatives (20.25 μg/L), and AFs (15.65 μg/L). African region had the highest mycotoxins concentration (73.95 μg/L) mostly due to the high levels reported in beers from Cameroon (293.02 μg/L), Malawi (132.34 μg/L), and Eastern Cape province (126.12 μg/L). The meta-regression indicated stability (p ≥ .05) of the global pooled concentration of mycotoxins in beers over the years, whereas FBs concentration increased. The intake of DON and its derivatives, FBs, ZEN and its derivatives, and OTA through beers is of concern in African countries. OTA is also of concern in Brazil and Belgium. Results show high mycotoxins concentration in beers worldwide and highlight the health risks through contaminated beer consumption.

Mycotoxins in artisanal beers: An overview of relevant aspects of the raw material, manufacturing steps and regulatory issues involved

The consumption of artisanal beer has increased worldwide. Artisanal beers can include malted or unmalted wheat, maize, rice and sorghum, in addition to the basic ingredients. These grains can be infected by toxigenic fungi in the field or during storage and mycotoxins can be produced if they find favorable conditions. Mycotoxins may not be eliminated throughout the beer brewing and be detected in the final product. In addition, modified mycotoxins may also be formed during beer brewing. This review compiles relevant information about mycotoxins produced by Aspergillus, Fusarium and Penicillium in raw material of artisanal beer, as well as updates information about the production and fate of mycotoxins during the beer brewing process. Findings highlight that malting conditions favor the production of mycotoxins by the fungi contaminating cereals. Therefore, good agricultural and postharvest mitigation strategies are the most effective options for preventing the growth of toxigenic fungi and the production of mycotoxins in cereals. However, the final concentration of mycotoxin in artisanal beer is difficult to predict as it depends on the initial concentration contained in the raw material and the processing conditions. The current lack of limits of mycotoxins in artisanal beer underestimates possible risks to human health. In addition, modified mycotoxins, not detected by conventional methods, may be formed in artisanal beers. Maximum tolerated limits for these contaminants must be urgently established based on scientific data about transfer of mycotoxins throughout the artisanal beer brewery process.

Transformation of Selected Trichothecenes during the Wheat Malting Production

The transformation of deoxynivalenol (DON), nivalenol (NIV), and their glucosides (DON3G and NIV3G) during the malting of grains of two wheat varieties was studied. The concentration of DON3G and NIV3G started to increase significantly before the concentration of DON and NIV increased. This may reflect the transformation of the parent mycotoxin forms into their glucosides due to xenobiotic detoxification reactions. After a sharp rise during the last 2 days of the process (day 6 and 7), the DON concentration reached 3010 ± 338 µg/kg in the Legenda wheat-based malt and 4678 ± 963 µg/kg in the Pokusa wheat-based malt. The NIV concentration, at 691 ± 65 µg/kg, remained the same as that in the dry grain. The concentration of DON3G in the Legenda and Pokusa wheat-based malt was five and three times higher, respectively, than that in the steeped grain. The concentration of NIV3G in the Legenda wheat-based malt was more than twice as high as that in the steeped grain. The sharp increase in the concentration of DON at the end of the malting process reflected the high pathogen activity. We set aside some samples to study a batch that was left undisturbed without turning and aeration, for the entire period of malting. The concentration of DON in the malt produced from the latter batch was 135% and 337% higher, for Legenda and Pokusa, respectively, than that in the malt produced from the batch that was turned and aerated. The NIV concentration was 22% higher in the latter batch.

Detection of Mycotoxins in Food Using Surface-Enhanced Raman Spectroscopy: A Review

Mycotoxins are toxic metabolites produced by fungi that contaminate many important crops worldwide. Humans are commonly exposed to mycotoxins through the consumption of contaminated food products. Mycotoxin contamination is unpredictable and unavoidable; it occurs at any point in the food production system under favorable conditions, and they cannot be destroyed by common heat treatments, because of their high thermal stability. Early and fast detection plays an essential role in this unique challenge to monitor the presence of these compounds in the food chain. Surface-enhanced Raman spectroscopy (SERS) is an advanced spectroscopic technique that integrates Raman spectroscopic molecular fingerprinting and enhanced sensitivity based on nanotechnology to meet the requirement of sensitivity and selectivity, but that can also be performed in a cost-effective and straightforward manner. This Review focuses on the SERS methodologies applied to date for qualitative and quantitative analysis of mycotoxins based on a variety of SERS substrates, as well as our perspectives on current limitations and future trends for applying this technique to mycotoxin analyses.

Rootlets, a Malting By-Product with Great Potential

Barley rootlets are the most abundant by-product from the malting industry. Due to the inherent association of the malting industry with brewing and distilling industries, it is also considered a by-product of these industries. Barley rootlets are produced during the germination step of malting. These rootlets are a valuable source of nutrition, with protein and fibre holding a large proportion of their composition. Barley rootlets are generally pelletised and used as animal fodder; however, their usage may not be limited to this. Efforts have been made to utilise barley rootlets as food ingredients, sources of enzymes, antioxidants, raw materials in fermentations, and in biochar production. Conversion of this by-product into other/new applications would reduce waste production from their industry origin and reduce some of the impending environmental concerns associated with by-product production. The current review focuses on providing information on the formation, production, and processing of barley rootlets, while also highlighting the composition, quality, and potential applications of barley rootlets.

NIR spectroscopy and chemometric tools to identify high content of deoxynivalenol in barley

Deoxynivalenol (DON) is one of the mycotoxins produced mainly by the Fusarium graminearum species complex in small grain cereals, including barley. This toxin can cause alimentary disorders, immune function depression and gastroenteritis. The negative health effects associated with DON coupled to the increasing concern about green and rapid methods of analysis motivated this study. In this context, near infrared (NIR) spectroscopy data were applied for exploratory analysis to distinguish barley with high and low levels of DON contamination (> or <1250 µg/kg according to the European Union threshold), by Partial Least Squares-Discriminant Analysis (PLS-DA), and to verify the performance of Partial Least Squares-Regression (PLS-R) to predict DON concentration in barley samples. Maximum values of specificity and sensitivity were achieved in the calibration set; 90.9% and 81.9% were observed in the cross-validation set for the PLS-DA classification model. PLS-R quantification of DON in barley presented low values of error (RMSEC = 101.94 µg/kg and RMSEP = 160.76 µg/kg). Thus, we found that NIR in combination with adequate chemometric tools could be applied as a green technique to monitor DON contamination in barley.

Application of LC-MS/MS in the Mycotoxins Studies

Mycotoxins are secondary metabolites produced by fungi of different species (mainly Aspergillus, Fusarium, and Penicillium) with toxic effects for humans and animals that can contaminate food and feed [...].

Determination of mycotoxins in beer by multi heart-cutting two-dimensional liquid chromatography tandem mass spectrometry method

Beer is one the most consumed alcoholic beverage in the world and its contamination with mycotoxins is of public health concern. This study reports a fast and automated analytical procedure based on a multi-heart-cutting two-dimensional liquid chromatography tandem mass spectrometry method using electrospray ionization for the determination of seven mycotoxins (aflatoxins B1, B2, G2 and G1, ochratoxin A, fumonisins B1 and B2) in beers. The developed method was based on the heart-cutting 2D- HPLC technique in which only the specific portions of the first dimension, in the retention time of analytes, were transferred into the second dimension for the further separation and successive determination. The method uses two different chromatographic columns; in the first dimension, 50 μL of sample was injected on first column, and mycotoxins elution regions were collected in a loop and transferred into the second column for the separation of analytes. Each column operated in gradient elution mode in order to eliminate interfering compounds and improve separation and peak shape. After the optimization, the method has been validated according to EU regulation and finally applied for the analysis of forty beer samples collected from Italian supermarkets. Among all mycotoxins studied, fumonisins B1 was the most widely distributed in analysed beers (>21%) in the range from 0.6 to 12.3 ng mL^-1. The automated methodology developed was able to determine accurately and simultaneously seven mycotoxins in beer. This provided a significant reduction of sample handle and, consequently of analysis time.

Natural occurrence of Alternaria mycotoxins in malting barley grains in the main producing region of Argentina

BACKGROUND

Barley (Hordeum vulgare L.) is one of the most important cereals worldwide, and its quality is affected by fungal contamination such as species of the genus Alternaria. No information is available about the occurrence of Alternaria mycotoxins in Argentinean barley grains, which is of concern, because they can be transferred into malt and beer. The aim of this study was to analyze the occurrence of alternariol (AOH), alternariol monomethyl ether (AME) and tenuazonic acid (TeA) in malting barley grains from the main producing region of Argentina during the 2014 and 2015 growing seasons.

RESULTS

The most frequent mycotoxin was AOH (64%), which was detected at higher levels (712 μg kg^-1 ) compared with other studies, followed by TeA (37%, 1522 μg kg^-1 ), while AME was present in five samples in the 2015 growing season only, with a mean of 4876 μg kg^-1 . A similar frequency of mycotoxin occurrence was observed in both years (80.8 vs 85.3%), but more diverse contamination was found in 2015, which was characterized by lower accumulated precipitation. Nevertheless, AOH was more frequently found in 2014 than in 2015 (80.8 and 47.1% respectively). A negative correlation between AOH concentration and temperature was observed. The susceptibility of different barley varieties to mycotoxin accumulation varied with the mycotoxin, geographical location and meteorological conditions.

CONCLUSION

The results obtained in the present work represent a tool for risk assessment of exposition to these mycotoxins and could be used by food safety authorities to determine the need for their regulation. Furthermore, the establishment of a hazard analysis and critical control point (HACCP) system to minimize fungal and mycotoxin contamination in barley from farm to processing could be apply to ensure food safety. © 2019 Society of Chemical Industry.