Degradation of the Alternaria mycotoxins alternariol, alternariol monomethyl ether, and altenuene upon bread baking

The fate of Alternaria toxin tenuazonic acid (TeA) during the processing chain of wheat flour products and risk control strategies for mycotoxins

The fate of Alternaria toxin tenuazonic acid (TeA) during the processing chain of wheat flour products was systemically evaluated. TeA was analyzed by liquid chromatography-mass spectrometry (LC-MS/MS) in wheat grains and the corresponding wheat flour products produced throughout the whole chain. The results indicated that TeA contamination in wheat grains largely determines the level of TeA toxin present in byproducts, semi-finished products, and finished products of the processing of four types of simulated processed wheat flour products (e.g., dry noodles, steamed breads, baked breads, and biscuits). The different food processing techniques had different effects on the fate of TeA. Wheat flour processing can reduce the TeA content in wheat grains by 58.7-83.2 %, indicating that wheat flour processing is a key step in reducing the TeA content in the food chain. Among the four types of wheat flour products, the decreases in TeA content in biscuits (69.8-76.7 %) were greater than those in dry noodles (15.5-22.3 %) and steamed breads (24.9-43.6 %). In addition, the decreasing effect of TeA was especially obvious in the wheat flour product chain with a high level of contamination. The processing factors (PFs) for TeA were as low as 0.20 for the four wheat processing methods and as high as 1.24 for the dry noodle processing method. At the average and 95th percentiles, dietary exposure to TeA in Chinese consumers including infants and young children did not exceed the relevant threshold value of toxicological concern (TTC) of TeA (1.5 µg/kg body weight per day), indicating an acceptable health risk for Chinese consumers via wheat flour products. These findings provide new insight into the fate of TeA in the food chain and mycotoxin control on the safety of wheat flour products and public health.

The characteristics, occurrence, and toxicological effects of alternariol: a mycotoxin

Alternaria species are mycotoxin-producing fungi known to infect fresh produce and to cause their spoilage. Humans get exposed to fungal secondary metabolites known as mycotoxin via the ingestion of contaminated food. Alternariol (AOH) (C14H10O5) is an isocoumarins produced by different species of Alternaria including Alternaria alternata. AOH is often found in grain, fruits and fruits-based food products with high levels in legumes, nuts, and tomatoes. AOH was first discovered in 1953, and it is nowadays linked to esophagus cancer and endocrine disruption due to its similarity to estrogen. Although considered as an emerging mycotoxin with no regulated levels in food, AOH occurs in highly consumed dietary products and has been detected in various masked forms, which adds to its occurrence. Therefore, this comprehensive review was developed to give an overview on recent literature in the field of AOH. The current study summarizes published data on occurrence levels of AOH in different food products in the last ten years and evaluates those levels in comparison to recommended levels by the regulating entities. Such surveillance facilitates the work of health risk assessors and highlights commodities that are most in need of AOH levels regulation. In addition, the effects of AOH on cells and animal models were summarized in two tables; data include the last two-year literature studies. The review addresses also the main characteristics of AOH and the possible human exposure routes, the populations at risk, and the effect of anthropogenic activities on the widespread of the mycotoxin. The commonly used detection and control methods described in the latest literature are also discussed to guide future researchers to focus on mitigating mycotoxins contamination in the food industry. This review aims mainly to serve as a guideline on AOH for mycotoxin regulation developers and health risk assessors.

Degradation of Alternaria mycotoxins by UV-C irradiation: Effect of selected process and exposure to food components

Alternariol (AOH) and alternariol monomethyl ether (AME) are two Alternaria mycotoxins with high occurrence rates in food systems. This study aimed to investigate the photodegradation of AOH and AME by ultraviolet-C (UV-C) irradiation. The effect of UV-C intensity, pH, treatment time, solvents and the exposure of food components were evaluated. After treated by UV-C irradiation at 3500 μW/cm² for 90 min, AOH samples in methanol, aqueous solution and solid state were degraded by 89.1%, 72.9% and 53.2%, respectively, while the degradation percentages of AME were 86.6%, 50.1% and 11.1%, respectively. Increasing irradiation intensity and prolonging irradiation time could significantly facilitate the degradation of AOH and AME. An alkaline environment (pH = 11) was more conducive to the degradation of toxins. In addition, 2.5 mg mL^-1 citric acid or malic acid increased the photodegradation of AOH and AME to 94.6% and 95.3%, 93.2% and 70.5%, respectively. However, protein, polyphenols and vitamin C exerted inhibitory effects on the degradation, while 10% glucose or sucrose reduced the photodegradation of AOH and AME to 65.9% and 40.3%. UV-C treatment could effectively reduce the content of AOH and AME, with the highest efficiency achieved in methanol and alkaline environment. By contrast, UV-C irradiation is more effective in degrading toxins in some liquid foods rich in organic acids but lacking in protein. The utilization of UV-C radiation appears to be a potentially useful approach for decreasing the underlying risk of Alternaria mycotoxin contamination in foods.

Removal of Alternaria mycotoxins exposed to different food components by cold plasma

Alternariol (AOH) and alternariol monomethyl ether (AME), the two Alternaria mycotoxins with the highest outbreak rates in food systems, could be effectively reduced by cold plasma. This research evaluated the impact of food components on the plasma removal of AOH and AME. The results showed that 6% whey protein or ovalbumin almost completely inhibited the reduction of AOH or AME. Polyphenols inhibited the removal of AOH and AME by up to 90.8% and 83.4%, respectively. Organic acids and Vc reduced AME removal by up to 43.4% and 31.9%, respectively, but had little effect on AOH removal. Sugars and amino acids could decrease both toxin removal by less than 10%. Proteins exhibited the most inhibitory effect on plasma removal of AOH and AME, followed by polyphenols, while the effect of other components was relatively small. AOH and AME removal by cold plasma was highly related to H₂O₂ produced during plasma discharge.

Recent Advances in Alternaria Phytotoxins: A Review of Their Occurrence, Structure, Bioactivity and Biosynthesis

Alternaria is a ubiquitous fungal genus in many ecosystems, consisting of species and strains that can be saprophytic, endophytic, or pathogenic to plants or animals, including humans. Alternaria species can produce a variety of secondary metabolites (SMs), especially low molecular weight toxins. Based on the characteristics of host plant susceptibility or resistance to the toxin, Alternaria phytotoxins are classified into host-selective toxins (HSTs) and non-host-selective toxins (NHSTs). These Alternaria toxins exhibit a variety of biological activities such as phytotoxic, cytotoxic, and antimicrobial properties. Generally, HSTs are toxic to host plants and can cause severe economic losses. Some NHSTs such as alternariol, altenariol methyl-ether, and altertoxins also show high cytotoxic and mutagenic activities in the exposed human or other vertebrate species. Thus, Alternaria toxins are meaningful for drug and pesticide development. For example, AAL-toxin, maculosin, tentoxin, and tenuazonic acid have potential to be developed as bioherbicides due to their excellent herbicidal activity. Like altersolanol A, bostrycin, and brefeldin A, they exhibit anticancer activity, and ATX V shows high activity to inhibit the HIV-1 virus. This review focuses on the classification, chemical structure, occurrence, bioactivity, and biosynthesis of the major Alternaria phytotoxins, including 30 HSTs and 50 NHSTs discovered to date.

Alternaria Mycotoxins: An Overview of Toxicity, Metabolism, and Analysis in Food

The genus Alternaria is widely distributed in the environment. Numerous species of the genus Alternaria can produce a variety of toxic secondary metabolites, called Alternaria mycotoxins. In this review, natural occurrence, toxicity, metabolism, and analytical methods are introduced. The contamination of these toxins in foodstuffs is ubiquitous, and most of these metabolites present genotoxic and cytotoxic effects. Moreover, Alternaria toxins are mainly hydroxylated to catechol metabolites and combined with sulfate and glucuronic acid in in vitro arrays. A more detailed summary of the metabolism of Alternaria toxins is presented in this work. To effectively detect and determine the mycotoxins in food, analytical methods with high sensitivity and good accuracy are also reviewed. This review will guide the formulation of maximum residue limit standards in the future, covering both toxicity and metabolic mechanism of Alternaria toxins.

Tea: Transfer of Mycotoxins from the Spiked Matrix into an Infusion

Recent surveys report the occurrence of Aspergillus and Penicillium metabolites (aflatoxins (AFLs), ochratoxin A (OTA), cyclopiazonic and mycophenolic acids (MPA), sterigmatocystin (STC), citrinin), Fusarium (trichothecenes, zearalenone (ZEA), fumonisins (FBs), enniatins (ENNs)) and Alternaria (alternariol (AOH), its methyl ether (AME), tentoxin (TE), and tenuazonic acid (TNZ)) toxins in dry Camellia sinensis and herbal tea samples. Since tea is consumed in the form of infusion, correct risk assessment needs evaluation of mycotoxins’ transfer rates. We have studied the transfer of AFLs, OTA, STC, deoxynivalenol (DON), ZEA, FBs, T-2, and HT-2 toxins, AOH, AME, TE, ENN A and B, beauvericin (BEA), and MPA from the spiked green tea matrix into an infusion under variation of preparation time and water characteristics (total dissolved solids (TDS) and pH). Analytes were detected by HPLC-MS/MS. The main factors affecting transfer rate proved to be mycotoxins’ polarity, pH of the resulting infusion (for OTA, FB2, and MPA) and matrix-infusion contact period. The concentration of mycotoxins increased by 20–50% within the first ten minutes of infusing, after that kinetic curve changed slowly. The concentration of DON and FB2 increased by about 10%, for ZEA, MPA, and STC it stayed constant, while for T-2, TE, AOH, and AFLs G1 and G2 it went down. Maximum transfer correlated well with analytes polarity. Maximum transfer of ENNs, BEA, STC, ZEA, and AOH into infusion was below 25%; AFLs—25–45%; DON, TE, and T-2 toxins 60–90%, FB1—80–100%. The concentration of OTA, MPA, and FB2 in the infusion depended on its pH. At pH about four, 20%, 40%, and 60% of these toxins transferred into an infusion, at pH about seven, their concentrations doubled. Water TDS did not affect transfer significantly.

Occurrence of Alternariol and Alternariolmonomethyl ether in edible oils: Their thermal stability and intake assessment in state of Uttar Pradesh, India

Alternariol (AOH) and Alternariol monomethyl ether (AME) mycotoxins are found to be present naturally in various food commodities, such as barley, oats, pepper, rye, sorghum, sunflower seeds, tomatoes, and wheat. A few epidemiological studies have correlated the consumption of Alternaria-contaminated cereal grains with higher occurrence of esophageal cancer in Chinese populations. In addition, several studies have reported the toxicological properties of Alternaria mycotoxins. However, surveillance data on AOH and AME occurrence are still limited. Therefore, the goal of this study was to determine the presence of AOH and AME in various commonly consumed, edible oils using HPLC-FLD method. Thirty four percent of samples were found positive for AOH and 35% for AME. Moreover, AOH retained 80% stability, while AME retained 84% stability, after deep frying for 25 min, which is an important factor with respect to Indian cooking style. To the best of our knowledge, this is the first report on the presence of Alternaria mycotoxins in edible oils and their probable dietary intake in Indian population. This surveillance study may help in formulating guidelines for Alternaria mycotoxin levels in India, which are not yet implemented by Food Safety and Standards Authority of India. PRACTICAL APPLICATIONS: At present, no safety guidelines exist for Alternaria mycotoxins in any part of the world. This study will help the regulatory bodies to set permissible levels of Alternaria mycotoxins to safeguard the health of consumers. This study shows that Alternaria mycotoxins are heat stable even after deep frying for 25 min. The data will also help to issue guidelines against exposure of these mycotoxins, keeping in the mind the heat stability factor.

Microfiltration results in the loss of analytes and affects the in vitro genotoxicity of a complex mixture of Alternaria toxins

Alternaria molds produce a variety of chemically diverse secondary metabolites with potentially adverse effects on human health. However, data on occurrence in food and human exposure is inconsistent for some of these mycotoxins. Membrane filtration is a frequent step in many sample preparation procedures for LC-MS-based methods analyzing food contaminants. Yet, little is known about the possibility of adsorptive phenomena that might result in analyte losses. Thus, we treated a complex extract of Alternaria toxins with several types of syringe filters and unraveled the impact on its chemical composition by LC-MS/MS. We observed significant, and in some cases complete, losses of compounds due to filtration. Particularly, two key Alternaria toxins, alternariol (AOH) and its monomethyl ether (AME), were heavily affected. As a comparison with published food surveys indicating a correlation of the type of filtration used with lower incidence reports in food, our results point at a possible underestimation of AME in past exposure assessment. Also, perylene quinones were greatly affected by filtration, underlining the importance to take this into consideration during analytical method development. Furthermore, we applied the comet assay in HT-29 cells to elucidate the impact of filtration on the genotoxicity of the extract. We observed strong coincidences with the loss of epoxide-carrying metabolites and also an intriguing induction of oxidative DNA damage by yet toxicologically uncharacterized Alternaria toxins. In conclusion, we highlight potential issues with sample filtration and call for a critical re-evaluation of previous food occurrence data in the light of the results at hand.

Removal of Alternaria mycotoxins from aqueous solution by inactivated yeast powder

BACKGROUND

Alternariol (AOH) and alternariol monomethyl ether (AME), produced by Alternaria spp., are the two mycotoxins with the highest outbreak rates in food systems. The purpose of this study was to investigate the removal of AOH and AME from aqueous solutions by inactivated yeast cells. The effects of strains, yeast powder amount, temperature, and pH were evaluated. The kinetics of AOH and AME adsorption on inactivated yeast cells was fitted with four models and a release assay was carried out.

RESULTS

All three tested yeasts could remove AOH and AME. GIM 2.119 was the most effective strain. The reduction rate of both AOH and AME could be as much as 100% with 40 g‧L^-1 of yeast powder. For both mycotoxins, pH = 9 was the best environment for toxin removal. The pseudo-second-order kinetic model was the best model, with R² ranging from 0.989 to 0.999. However, the R² of the pseudo-first-order and Elovich models was also relatively high. Alternariol and AME could be partially eluted by methanol and acetonitrile.

CONCLUSION

The inactivated yeast cells could effectively remove AOH and AME. This was best fitted by the pseudo-second-order model. The release assay suggested that the adsorption of Alternaria mycotoxins was partially reversible. The results of this study provide a theoretical basis for the removal of Alternaria mycotoxins from food systems and are useful for the investigation of the mechanisms involved in mycotoxin adsorption by inactivated yeast cells. © 2020 Society of Chemical Industry.

Pyrosequencing scrutiny of bacterial and fungal communities in two Sudanese sorghum-based fermented foods

Purpose

Several fermented foods are produced from sorghum flour in Africa, especially in the dryland regions where it is the principal crop. It is important to explore the microbial communities in these foods to improve their quality and organoleptic properties. In this study, the bacterial and fungal communities of two popular sorghum-based fermented foods in Sudan (kisra and hulumur) were analyzed, for the first time, using a culture-independent method of next-generation sequencing.

Methods

Fermented doughs for kisra and hulumur production were prepared according to the traditional approach, and then the bacterial and fungal communities were investigated using high-throughput sequencing.

Results

Firmicutes and Proteobacteria phyla were the predominant bacteria in both fermented doughs. At the genus level, the bacterial community was dominated by lactic acid bacteria, primarily Lactobacillus and Pediococcus, which represented 95.7% and 72% of the bacterial population in kisra and hulumur, respectively. Next, acetic acid bacteria (Gluconobacter and Acetobacter) were subdominant in hulumur. The fungal community was more heterogeneous among the fermented doughs. Zygomycota (85.5%) comprised the major phylum in kisra fermented dough, whereas Ascomycota (99.5%) was predominant in hulumur. The major fungal genera, Rhizopus, Alternaria, Penicillium, Gibberella, Lasiodiplodia, and Aspergillus, were extremely varied between the fermented doughs.

Conclusion

Exploration of kisra and hulumur microbial community structure will expand the knowledge about their microbiota to manipulate the microbial community and improve their quality and organoleptic properties using different microbial recipes.

Parallel validation of a green-solvent extraction method and quantitative estimation of multi-mycotoxins in staple cereals using LC-MS/MS

In this study, 15 different mycotoxins were estimated in three staple cereals from selected agro-ecological regions in Nigeria using a 'novel' green extraction method, pressurized hot water extraction (PHWE) in comparison to a conventional solvent extraction method. Discrimination of the results of PHWE and solvent extraction using principal component analysis (PCA) and orthogonal projection to latent structures discriminate analysis (OPLS-DA) did not yield any differential clustering patterns. All maize samples (n = 16), 32% (n = 38) of sorghum and 35% (n = 37) of millet samples were positive for at least one of the 15 tested mycotoxins. Contamination levels for the cereals were higher in the warm humid rain forest region and gradually decreased towards the hot and arid region in the north of the country. The results demonstrate the applicability of PHWE as a possible alternative extraction method to conventional methods of extraction, which are solvent based.

Molecular Identification and Mycotoxin Production by Alternaria Species Occurring on Durum Wheat, Showing Black Point Symptoms

Black point is a fungal disease of wheat, mainly associated with mycotoxigenic Alternaria species. Affected wheat kernels are characterized by dark brown discolouration of the embryo region and reduction of grain quality. Potential risk is the possible accumulation of Alternaria mycotoxins, alternariol (AOH), alternariol-monomethyl ether (AME), tenuazonic acid (TA), and altenuene (ALT), provided by haemato-toxic, genotoxic, and mutagenic activities. One hundred and twenty durum wheat samples belonging to 30 different genotypes grown in Bologna and Modena areas, in Italy, showing black point symptoms, were analyzed for Alternaria species and their mycotoxin contamination. Alternariol was selected as an indicator of the capability of the Alternaria species to produce mycotoxin in vivo in field conditions. The data showed that Alternaria species occurred in 118 out of 120 wheat kernels samples, with the incidence of infected kernels ranging between 1% and 26%. Moreover, AOH was detected by using a HPLC with a diode array detector (LC-DAD) in 98 out of 120 samples with values ranging between 24 and 262 µg Kg⁻¹. Ninety-two Alternaria representative strains, previously identified morphologically, were identified at species/section level using gene sequencing, and therefore were analyzed for their mycotoxin profiles. Eighty-four strains, phylogenetically grouped in the Alternaria section, produced AOH, AME, and TA with values up to 8064, 14,341, and 3683 µg g⁻¹, respectively, analyzed by using a LC-DAD. On the other hand, eight Alternaria strains, included in Infectoriae Section, showed a very low or no capability to produce mycotoxins.

Preliminary Survey of Alternaria Toxins Reduction during Fermentation of Whole Wheat Dough

The aim of this study was to investigate the fate of the most common Alternaria toxins found in wheat-tenuazonic acid (TeA), alternariol (AOH), and alternariol monomethyl ether (AME) during sourdough processing. For this purpose, spiked whole wheat flour, 3% sourdough starter, 0.5% of baker's yeast, and 105% of water calculated on flour weight as a base were used as raw materials. Spiked whole wheat dough was fermented for 4 h, 8 h, 12 h, 24 h, and 48 h at 25 °C, and at each point the fermented dough samples were taken, frozen, lyophilized, grounded, and stored until further analysis. To study the effect of sourdough processing on TeA, AOH and AME content, the validated method of high-performance liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) for these mycotoxins was used. Mathematical models of Alternaria toxins reduction were developed in the form of Four Parameter Logistic Regression function. The maximum reduction of TeA, AOH, and AME levels was archived at 48 h of dough fermentation at 25 °C compared with dough after kneading (0 h). Under these conditions, a reduction of the toxin levels of 60.3 %, 41.5%, and 24.1% was observed for TeA, AOH, and AME, respectively.

Effect of Atmospheric Cold Plasma Treatments on Reduction of Alternaria Toxins Content in Wheat Flour

Beside Fusarium toxins, Alternaria toxins are among the most commonly found mycotoxins in wheat and wheat products. Currently, investigations of possibilities of reduction of Alternaria toxins in the wheat-processing chain are limited. Therefore, the aim of this study was to explore the potency of cold atmospheric plasma treatments, as a new non-thermal approach, for reduction of alternariol (AOH), alternariol monomethyl ether (AME) and tentoxin (TEN) content in spiked white wheat flour samples. Samples were treated with plasma generated in the air during 30 s to 180 s, with an increment step of 30 s, and at four varying distances from the cold plasma source (6 mm, 21 mm, 36 mm and 51 mm). The reduction of the Alternaria toxins content in samples after treatment was monitored by high performance liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The maximum reduction of the examined Alternaria toxins was obtained by treatment performed at 6 mm distance from the plasma source, lasting 180 s, resulting in reductions of 60.6%, 73.8% and 54.5% for AOH, AME and TEN, respectively. According to the obtained experimental results, five empirical models in the form of the second-order polynomials were developed for the prediction of AOH, AME and TEN reduction, as well as the temperature and the moisture content of the wheat flour, that gave a good fit to experimental data and were able to predict the response variables successfully. The developed second-order polynomial models showed high coefficients of determination for prediction of experimental results (between 0.918 and 0.961).

Bioavailability, metabolism, and excretion of a complex Alternaria culture extract versus altertoxin II: a comparative study in rats

Despite the frequent infection of agricultural crops by Alternaria spp., their toxic secondary metabolites and potential food contaminants lack comprehensive metabolic characterization. In this study, we investigated their bioavailability, metabolism, and excretion in vivo. A complex Alternaria culture extract (50 mg/kg body weight) containing 11 known toxins and the isolated lead toxin altertoxin II (0.7 mg/kg body weight) were administered per gavage to groups of 14 Sprague Dawley rats each. After 3 h and 24 h, plasma, urine and feces were collected to determine toxin recoveries. For reliable quantitation, an LC–MS/MS method for the simultaneous detection of 20 Alternaria toxins and metabolites was developed and optimized for either biological matrix. The obtained results demonstrated efficient excretion of alternariol (AOH) and its monomethyl ether (AME) via feces (> 89%) and urine (> 2.6%) after 24 h, while the majority of tenuazonic acid was recovered in urine (20 and 87% after 3 and 24 h, respectively). Moreover, modified forms of AOH and AME were identified in urine and fecal samples confirming both, mammalian phase-I (4-hydroxy-AOH) and phase-II (sulfates) biotransformation in vivo. Despite the comparably high doses, perylene quinones were recovered only at very low levels (altertoxin I, alterperylenol, < 0.06% in urine and plasma, < 5% in feces) or not at all (highly genotoxic, epoxide-holding altertoxin II, stemphyltoxin III). Interestingly, altertoxin I was detected in all matrices of rats receiving altertoxin II and suggests enzymatic de-epoxidation in vivo. In conclusion, the present study contributes valuable information to advance our understanding of the emerging Alternaria mycotoxins and their relevance on food safety.

The Fate of Altertoxin II During Tomato Processing Steps at a Laboratory Scale

Among various agricultural crops, tomatoes are particularly prone to Alternaria infections, which are frequently resulting in economic losses and mycotoxin contamination. To investigate potential health concerns implied for consumers, we simulated the storage and food processing steps of intact and blended tomatoes after addition of the highly genotoxic secondary metabolite altertoxin II. We observed a significant decrease in altertoxin II concentrations in samples stored at room temperature and particularly those undergoing thermal treatment by employing a validated LC-MS/MS method. When kept at room temperature, 87-90% of ATX-II was recovered after 1.5 h in raw tomato purees and purees heated before ATX-II addition, and 47-49% were recovered after 24 h. In intact tomato fruits the recovery was 23% after 1.5 h and <1% after 24 h. In heated purees (100°C for 30 min after ATX-II addition), also only minor concentrations accounting for 2-4% were determined. Moreover, the reduction of the compound's epoxide group to the alcohol, i.e., the formation of altertoxin I was demonstrated in intact tomato fruits (7-12%), suggesting enzymatic biotransformation of the xenobiotic by the plant's metabolism.

Contamination of fresh and dried tomato by Alternaria toxins in southern Italy

In the present investigation, fresh and dried tomato samples from markets and packinghouses located in Apulia region (southern Italy) were analysed for Alternaria toxins. All samples proved to be contaminated by tenuazonic acid (TeA); in particular, dried tomatoes were contaminated in the range 425-81,592 µg/kg, while fresh tomatoes were in the range 11-4560 µg/kg. The second most abundant toxin was alternariol monomethyl ether (AME), followed by tentoxin (TEN) and alternariol (AOH). Overall dried tomatoes were more contaminated than fresh ones, although this seemed not directly related to the presence of sodium chloride, utilized in the drying process. Five representative Alternaria isolates within those collected from samples proved to be one Alternaria arborescens (A215) and four Alternaria alternata. Within the latter species, one strain belonged to morphotype tenuissima (A216), and three to alternata (A214, A217 and A218). They were confirmed to produce TeA, AOH, and AME in vitro. This study demonstrates the possible risk for consumers' health related to the consumption of contaminated fresh and dried tomatoes, and thus the need for suitable control strategies.

Effect of Wheat Milling Process on the Distribution of Alternaria Toxins

Alternaria toxins are mycotoxins produced by various Alternaria species which, besides the Fusarium species, represent the principal contaminants of wheat worldwide. As currently, only limited information on the behaviour of Alternaria toxins during processing of cereals is available, the objective of this study was to investigate the effect of the dry milling process of wheat on Alternaria toxins distribution. Alternariol (AOH), alternariol monomethyl ether (AME) and tenuazonic acid (TeA) content were analysed by high performance liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) in all milling fractions of untreated (control), fungicide-treated, Alternaria tenuissima inoculated and commercial wheat sample. After dry milling process, in last break and milling flows and by-products, increased concentration of examined Alternaria toxins was detected. TeA was quantified in almost all milling fractions in all tested wheat samples, while AOH and AME were detectable mostly in last break and milling flows and by-products. In respect to the contamination with Alternaria toxins, white flour can be considered as relatively safe product. Since Alternaria toxins are concentrated mainly in the peripheral parts of the kernel, a special attention should be given to their content in low-grade flours and milling by-products.

Alternaria mycotoxins in grains from Albania: alternariol, alternariol monomethyl ether, tenuazonic acid and tentoxin

The presence of four Alternaria toxins in maize and wheat harvested in 2014 and 2015 in Albania was investigated. In total, 45 samples of maize and 71 samples of wheat were collected from the country’s main producing regions. The presence of alternariol (AOH), alternariol monomethyl ether (AME), tenuazonic acid (TeA) and tentoxin (TTX) was studied by an LC-MS/MS method. The incidence of Alternaria toxins in maize was 45.2% in the year 2014 and 7.1% in 2015, and the contamination rate in wheat was 82.9% in 2014 and 86.1% in 2015. Considering maize and wheat samples together, 65.2 and 64.0% of samples were contaminated by Alternaria toxins in the harvesting years 2014 and 2015, respectively. The occurrence rate was much higher in wheat than in maize, but the concentrations were higher in maize. The highest concentration of total Alternaria toxins in maize was 1,283 μg/kg (mean 243.0 μg/kg, median 110.2 μg/kg), while the maximum concentration in wheat was 175.7 μg/kg (mean 29.9 μg/kg, median 16.5 μg/kg). TeA was the major Alternaria mycotoxin detected. It was found in 70 out of 116 samples (60.3%). Chronic exposure of the adult population in Albania to Alternaria toxins through cereal consumption was assessed by the estimated daily intake (EDI) taking into account daily consumption of wheat and maize of 380 and 4.9 g, respectively. The main contribution to chronic dietary exposure was by TeA originating from wheat, with EDIs of 88.6-94.1 ng/kg body weight (bw) per day in 2014 and 152.7-155.5 ng/kg bw per day in 2015. TTX EDIs were 7.8- 34.0 and 10.6-38.7 ng/kg bw per day in 2014 and 2015, respectively. The contribution of AOH and AME originating from wheat was 0-31.7 ng/kg bw per day. The contribution of Alternaria toxins through maize consumption was significantly lower.

Occurrence of Alternaria mycotoxins and quantification of viable Alternaria spp. during the food processing of tomato products in Spain

The occurrence of two Alternaria mycotoxins, alternariol (AOH) and alternariol monomethyl ether (AME) and the presence of conidia from Alternaria spp., were investigated throughout the food production chain of two businesses, one which uses organic fruit and the other non-organic. For this purpose, a propidium monoazide (PMA) treatment followed by a quantitative Real Time PCR (qPCR) was used to detect and quantify viable conidia exclusively. Results demonstrated that 68.4% of the total raw fruit analysed was contaminated with viable Alternaria spp. Regarding the mycotoxin occurrence, only a few samples were contaminated with AME, while 35% of raw tomatoes tested positive for AOH in the organic producer and 21% in the non-organic producer. AOH was present in samples analysed before heat treatment, while almost no mycotoxins were found in the final products of the organic producer. However, in the non-organic producer, 47% of the tomato concentrates were contaminated.

Forthcoming Challenges in Mycotoxins Toxicology Research for Safer Food-A Need for Multi-Omics Approach

The presence of mycotoxins in food represents a severe threat for public health and welfare, and poses relevant research challenges in the food toxicology field. Nowadays, food toxicologists have to provide answers to food-related toxicological issues, but at the same time they should provide the appropriate knowledge in background to effectively support the evidence-based decision-making in food safety. Therefore, keeping in mind that regulatory actions should be based on sound scientific findings, the present opinion addresses the main challenges in providing reliable data for supporting the risk assessment of foodborne mycotoxins.

Alternaria Species and Their Associated Mycotoxins

The genus Alternaria includes more than 250 species. The traditional methods for identification of Alternaria species are based on morphological characteristics of the reproductive structures and sporulation patterns under controlled culture conditions. Cladistics analyses of "housekeeping genes" commonly used for other genera, failed to discriminate among the small-spored Alternaria species. The development of molecular methods achieving a better agreement with morphological differences is still needed. The production of secondary metabolites has also been used as a means of classification and identification. Alternaria spp. can produce a wide variety of toxic metabolites. These metabolites belong principally to three different structural groups: (1) the dibenzopyrone derivatives, alternariol (AOH), alternariol monomethyl ether (AME), and altenuene (ALT); (2) the perylene derivative altertoxins (ATX-I, ATX-II, and ATX II); and (3) the tetramic acid derivative, tenuazonic acid (TeA). TeA, AOH, AME, ALT, and ATX-I are the main. Certain species in the genus Alternaria produce host-specific toxins (HSTs) that contribute to their pathogenicity and virulence. Alternaria species are plant pathogens that cause spoilage of agricultural commodities with consequent mycotoxin accumulation and economic losses. Vegetable foods infected by Alternaria rot could introduce high amounts of these toxins to the human diet. More investigations on the toxic potential of these toxins and their hazard for human consumption are needed to make a reliable risk assessment of dietary exposure.

AlternariaMycotoxins in Food and Feed: An Overview

Alternariais one of the major mycotoxigenic fungal genera with more than 70 reported metabolites.Alternariamycotoxins showed notably toxicity, such as mutagenicity, carcinogenicity, induction of DNA strand break, sphingolipid metabolism disruption, or inhibition of enzymes activity and photophosphorylation. This review reports on the toxicity, stability, metabolism, current analytical methods, and prevalence ofAlternariamycotoxins in food and feed through the most recent published research. Half of the publications were focused on fruits, vegetables, and derived products—mainly tomato and apples—while cereals and cereal by-products represented 38%. The most studied compounds were alternariol, alternariol methyl ether, tentoxin, and tenuazonic acid, but altenuene, altertoxins (I, II, and III), and macrosporin have been gaining importance in recent years. Solid-liquid extraction (50%) with acetonitrile or ethyl acetate was the most common extraction methodology, followed by QuEChERS and dilution-direct injection (both 14%). High- and ultraperformance liquid chromatography coupled with tandem mass spectrometry was the predominant determination technique (80%). The highest levels of alternariol and alternariol methyl ether were found in lentils, oilseeds, tomatoes, carrots, juices, wines, and cereals. Tenuazonic acid highest levels were detected in cereals followed by beer, while alternariol, alternariol methyl ether, tenuazonic acid, and tentoxin were found in legumes, nuts, and oilseeds.

Possibility of Alternaria toxins reduction by extrusion processing of whole wheat flour

This study represents the first report about possibility of reduction of Alternaria toxins in wheat using the extrusion process. Effects of extrusion processing parameters - moisture content (w=16, 20, 24g/100g), feeding rate (q=15, 20, 25kg/h), and screw speed (v=300, 390, 480rpm), on reduction rate of tenuazonic acid (TeA), alternariol (AOH) and alternariol monomethyl ether (AME), in whole wheat flour were investigated. Temperature ranged between 111.1 and 160.8°C, while the absolute pressure was from 0.17 to 0.23MPa. The simultaneous influence of w and v was the most important for TeA reduction (p<0.05), while v and q were the most influential for AOH reduction (p<0.01). Level of AME reduction was mostly influenced by w and v (p<0.10). Optimal parameters for reduction of all three Alternaria toxins were as follows: w=24g/100g, q=25kg/h, v=390rpm, with a reduction of 65.6% for TeA, 87.9% for AOH and 94.5% for AME.

Natural occurrence of four Alternaria mycotoxins in tomato- and citrus-based foods in China

A total of 70 tomato-based and 86 citrus-based products collected in China were analyzed for alternariol, alternariol monomethyl ether, tentoxin, and tenuazonic acid by ultraperformance liquid chromatography–electrospray ionization–tandem mass spectrometry. No toxins were found in any fresh tomato or citrus fruit samples. Tenuazonic acid was the predominant toxin detected in all tomato ketchup (10.2–1787 μg/kg) and tomato juice samples (7.4–278 μg/kg). Alternariol was quantitated at higher level than alternariol monomethyl ether with the ratio of alternariol/alternariol monomethyl ether ranging from 0.37 to 104 in 14 alternariol-positive tomato ketchup samples. Tentoxin was detected at much lower levels in all samples analyzed. Some citrus juice samples were positive for tenuazonic acid and alternariol monomethyl ether. It is necessary to conduct a systemic surveillance of Alternaria toxins in raw and processed foods to provide the scientific basis for risk assessment of dietary exposure to these toxins in Chinese populations.

Using SILAC proteomics to investigate the effect of the mycotoxin, alternariol, in the human H295R steroidogenesis model

The mycotoxin alternariol (AOH) is an important contaminant of fruits and cereal products. The current study sought to address the effect of a non-toxic AOH concentration on the proteome of the steroidogenic H295R cell model. Quantitative proteomics based on stable isotope labeling by amino acids in cell culture (SILAC) coupled to 1D-SDS-PAGE-LC-MS/MS was applied to subcellular-enriched protein samples. Gene ontology (GO) and ingenuity pathway analysis (IPA) were further carried out for functional annotation and identification of protein interaction networks. Furthermore, the effect of AOH on apoptosis and cell cycle distribution was also determined by the use of flow cytometry analysis. This work identified 22 proteins that were regulated significantly. The regulated proteins are those involved in early stages of steroid biosynthesis (SOAT1, NPC1, and ACBD5) and C21-steroid hormone metabolism (CYP21A2 and HSD3B1). In addition, several proteins known to play a role in cellular assembly, organization, protein synthesis, and cell cycle were regulated. These findings provide a new framework for studying the mechanisms by which AOH modulates steroidogenesis in H295R cell model.

Alternaria toxins alternariol and alternariol monomethyl ether in grain foods in Canada

Alternaria alternata has been reported to be the most common fungus on Canadian Western wheat. The Alternaria toxins alternariol (AOH) and alternariol monomethyl ether (AME) are mutagenic in vitro and there is also limited evidence for carcinogenic properties. They have been found in wheat from Europe, Argentina, China and Australia, but they have not been looked for in Canadian grains or grain foods. In the present study, 83 samples of grain-based food sold in Canada, including flour, bran, breakfast cereals, infant cereals and bread, were analysed for AOH and AME using extraction with methanol, clean-up on combined aminopropyl/C18 solid phase extraction (SPE) columns, and liquid chromatography (LC) with tandem mass spectrometric (MS/MS) determination. The overall average recoveries of AOH and AME from a variety of spiked cereal foods (n = 13) were 45 ± 9% and 53 ± 9%, which could be attributed mainly to MS matrix effects The instrumental limits of detection (LOD) were 0.34 ng/g and 0.13 ng/g for AOH and AME, respectively, and the instrumental limits of quantitation (LOQ) were 1.1 and 0.43 ng/g. Of 83 samples analysed, 70 were positive for AOH (up to 63 ng/g, in a soft wheat bran) and 64 contained AME (up to 12 ng/g in a bran-based breakfast cereal). Of particular interest was the presence of AOH and/or AME in 27 out of 30 infant foods (up to 4.4 ng/g and 9.0 ng/g, respectively, in a sample of multigrain cereal).

Developments in mycotoxin analysis: an update for 2010-2011

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2010 and mid-2011. It covers the major mycotoxins: aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxin, patulin, trichothecenes, and zearalenone. Analytical methods for mycotoxins continue to be developed and published. Despite much interest in immunochemical methods and in the rapid development of LC-MS methodology, more conventional methods, sometimes linked to novel clean-up protocols, have also been the subject of research publications over the above period. Occurrence of mycotoxins falls outside the main focus of this review; however, where relevant to analytical method development, this has been mentioned.

Widespread occurrence of low levels of alternariol in apple and tomato products, as determined by comparative immunochemical assessment using monoclonal and polyclonal antibodies

This study investigated the production of polyclonal (pAB) antibodies and the first time production of monoclonal (mAB) antibodies against the mycotoxin alternariol, and their implementation in enzyme immunoassay (EIA) for the rapid determination of alternariol in foods. Both EIAs were highly sensitive, with detection limits (IC₂₀) of 35 ± 6.9 pg/mL (mAb EIA) and 59 ± 16 pg/mL (pAb EIA). Food products (n = 109; apple and tomato products, white wine) from German retail shops were analyzed. At a detection limit of 1-2 μg/kg, alternariol at 1-13 μg/kg was found with high frequency in apple (67%) and tomato (93%) products. Tomatoes with visible signs of Alternaria infection, stored at room temperature for up to 4 weeks, contained alternariol at levels up to 50 mg/kg, as determined by EIA and HPLC-FLD. It is concluded that the alternariol immunoassays present a versatile screening tool which could facilitate food control for Alternaria toxins.