Survey of Alternaria toxin contamination in food from the German market, using a rapid HPLC-MS/MS approach

Mycotoxins in food: Occurrence, health implications, and control strategies-A comprehensive review

Mycotoxins are secondary metabolites produced by various filamentous fungi, including Aspergillus, Fusarium, Penicillium, Alternaria, Claviceps, Mucor, Trichoderma, Trichothecium, Myrothecium, Pyrenophora, and Stachybotrys. They can contaminate various plants or animal foods, resulting in a significant loss of nutritional and commercial value. Several factors contribute to mycotoxin production, such as humidity, temperature, oxygen levels, fungal species, and substrate. When contaminated food is consumed by animals and humans, mycotoxins are rapidly absorbed, affecting the liver, and causing metabolic disorders. The detrimental effects on humans and animals include reduced food intake and milk production, reduced fertility, increased risk of abortion, impaired immune response, and increased occurrence of diseases. Therefore, it is imperative to implement strategies for mycotoxin control, broadly classified as preventing fungal contamination and detoxifying their toxic compounds. This review aims to discuss various aspects of mycotoxins, including their occurrence, and risk potential. Additionally, it provides an overview of mycotoxin detoxification strategies, including the use of mycotoxin absorbents, as potential techniques to eliminate or mitigate the harmful effects of mycotoxins and masked mycotoxins on human and animal health while preserving the nutritional and commercial value of affected food products.

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.

Saturated brine dissolution and liquid-liquid extraction combined with UPLC-MS/MS for the detection of typical Alternaria toxins in pear paste

BACKGROUND

Alternaria can infest pears to produce metabolites, which can contaminate pears and their processed products. Pear paste, one of the most important pear-based products, is popular among Chinese consumers especially for its cough relieving and phlegm removal properties. Although people are concerned about the risk of Alternaria toxins in many agro-foods and their products, little is known about the toxins in pear paste.

RESULTS

A method was developed for the determination of tenuazonic acid, alternariol, alternariol menomethyl ether, altenuene and tentoxin in pear paste by ultra-performance liquid chromatography tandem mass spectrometry with saturated sodium sulphate dissolution and acidified acetonitrile extraction. The mean recoveries of the five toxins were 75.3-113.8% with relative standard deviations of 2.8-12.2% at spiked levels of 1.0-100 μg kg-1 . Alternaria toxins were detected in 53 out of 76 samples, with a detection rate of 71.4%. Tenuazonic acid (67.1%), alternariol (35.5%), tentoxin (23.7%) and alternariol monomethyl ether (7.9%) were detected in all samples at concentrations of < limit of quantification (LOQ)-105.0 μg kg-1 , < LOQ-32.1 μg kg-1 , < LOQ-74.2 μg kg-1 and < LOQ-15.1 μg kg-1 , respectively. Altenuene was never found in pear paste samples. Tenuazonic acid, alternariol, tentoxin and alternariol menomethyl ether should be focused on due to their toxicity and detection rates.

CONCLUSION

To the best of our knowledge, this is the first report on the detection method and residue levels of Alternaria toxins in pear paste. The proposed method and research data can provide technical support for the Chinese government to continuously monitor and control Alternaria toxins in pear paste, especially tenuazonic acid. It can also provide a useful reference for related researchers. © 2023 Society of Chemical Industry.

Simultaneous determination of zearalenone and alternariol mycotoxins in oil samples using mixed molecularly imprinted polymer beads

This work reports the optimization of a method using Molecularly Imprinted Polymers (MIPs) for the simultaneous determination of zearalenone and alternariol mycotoxins. The method was optimized using a chemometric approach where in the optimized conditions, the cartridges with a mixture (50:50, w/w) of both MIPs, were loaded with 30 mL of sample, washed with 2 mL of ACN/water (20/80, v/v) and eluted with 2.5 mL of trifluoroacetic acid/MeOH (3/97, v/v). The extracts were analyzed by HPLC coupled to a fluorescence detector (FLD). The optimized method has been applied and validated to the analysis of the mycotoxins in maize, sunflower and olive oils samples with a limit of detection of 5 and 2 µg kg^-1, respectively. Recoveries were in the range of 94 % to 108 % (RSD < 6 %) for zearalenone and 92 % to 113 % (RSD < 5 %) for alternariol. The results were confirmed by HPLC-MS/MS.

Using In Silico Approach for Metabolomic and Toxicity Prediction of Alternariol

Alternariol is a metabolite produced by Alternaria fungus that can contaminate a variety of food and feed materials. The objective of the present paper was to provide a prediction of Phase I and II metabolites of alternariol and a detailed ADME/Tox profile for alternariol and its metabolites using an in silico working model based on the MetaTox, SwissADME, pKCMS, and PASS online computational programs. A number of 12 metabolites were identified as corresponding to the metabolomic profile of alternariol. ADME profile for AOH and predicted metabolites indicated a moderate or high intestinal absorption probability but a low probability to penetrate the blood-brain barrier. In addition to cytotoxic, mutagenic, carcinogenic, and endocrine disruptor effects, the computational model has predicted other toxicological endpoints for the analyzed compounds, such as vascular toxicity, haemato-toxicity, diarrhea, and nephrotoxicity. AOH and its metabolites have been predicted to act as a substrate for different isoforms of phase I and II drug-metabolizing enzymes and to interact with the response to oxidative stress. In conclusion, in silico methods can represent a viable alternative to in vitro and in vivo tests for the prediction of mycotoxins metabolism and toxicity.

Natural Occurrence of Alternaria Toxins in Citrus-Based Products Collected from China in 2021

A total of 181 citrus-based products, including dried fruits, canned fruits, and fruit juices, collected from China and from abroad in 2021 were analyzed for the four Alternaria toxins (ALTs): alternariol (AOH), alternariol monomethyl ether (AME), tentoxin (TEN), and tenuazonic acid (TeA) via ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS). Although the concentrations of the four ALTs varied by product and geographically, TeA was the predominant toxin followed by AOH, AME, and TEN. Products made in China showed higher levels of ALTs than those made abroad. Maximum levels of TeA, AOH, and AME in analyzed domestic samples were 4.9-fold, 1.3-fold, and 1.2-fold, respectively, higher than those in imported products. Furthermore, 83.4% (151/181) of the analyzed citrus-based products were contaminated with at least two or more ALTs. There were significant positive correlations between AOH and AME, AME and TeA, and TeA and TEN in all analyzed samples. More importantly, the solid and the condensed liquid products had higher concentrations of ALTs than the semi-solid product samples, as well as tangerines, pummelos, and grapefruits compared to the other kinds of citrus-based products. In conclusion, co-contamination with ALTs in commercially available Chinese citrus-based products was universal. Extensive and systematic surveillance of ALTs in citrus-based products, both domestic and imported, is required to obtain more scientific data for the determination of the maximum allowable concentrations of ALTs in China.

Root uptake and metabolization of Alternaria toxins by winter wheat plants using a hydroponic system

Fungi of the genus Alternaria are ubiquitous in the environment. Their mycotoxins can leach out of contaminated plants or crop debris into the soil entering the plant via the roots. We aim to evaluate the importance of this entry pathway and its contribution to the overall content of Alternaria toxins (ATs) in wheat plants to better understand the soil-plant-phytopathogen system. A hydroponic cultivation system was established and wheat plants were cultivated for up to two weeks under optimal climate conditions. One half of the plants was treated with a nutrient solution spiked with alternariol (AOH), alternariol monomethyl ether (AME), and tenuazonic acid (TeA), whereas the other half of the plants was cultivated without mycotoxins. Plants were harvested after 1 and 2 weeks and analyzed using a QuEChERS-based extraction and an in-house validated LC-MS/MS method for quantification of the ATs in roots, crowns, and leaves separately. ATs were taken up by the roots and transported throughout the plant up to the leaves after 1 as well as 2 weeks of cultivation with the roots showing the highest ATs levels followed by the crowns and the leaves. In addition, numerous AOH and AME conjugates like glucosides, malonyl glucosides, sulfates, and di/trihexosides were detected in different plant compartments and identified by high-resolution mass spectrometry. This is the first study demonstrating the uptake of ATs in vivo using a hydroponic system and whole wheat plants examining both the distribution of ATs within the plant compartments and the modification of ATs by the wheat plants.

Stress Response to Climate Change and Postharvest Handling in Two Differently Pigmented Lettuce Genotypes: Impact on Alternaria alternata Invasion and Mycotoxin Production

Many species of Alternaria are important pathogens that cause plant diseases and postharvest rots. They lead to significant economic losses in agriculture and affect human and animal health due to their capacity to produce mycotoxins. Therefore, it is necessary to study the factors that can result in an increase in A. alternata. In this study, we discuss the mechanism by which phenol content protects from A. alternata, since the red oak leaf cultivar (containing higher phenols) showed lower invasion than the green one, Batavia, and no mycotoxin production. A climate change scenario enhanced fungal growth in the most susceptible cultivar, green lettuce, likely because elevated temperature and CO₂ levels decrease plant N content, modifying the C/N ratio. Finally, while the abundance of the fungi was maintained at similar levels after keeping the lettuces for four days at 4 °C, this postharvest handling triggered TeA and TEN mycotoxin synthesis, but only in the green cultivar. Therefore, the results demonstrated that invasion and mycotoxin production are cultivar- and temperature-dependent. Further research should be directed to search for resistant cultivars and effective postharvest strategies to reduce the toxicological risk and economic losses related to this fungus, which are expected to increase in a climate change scenario.

Development of Acid Hydrolysis-Based UPLC–MS/MS Method for Determination of Alternaria Toxins and Its Application in the Occurrence Assessment in Solanaceous Vegetables and Their Products

In this work, we proposed an acid hydrolysis-based analytical method for the detection of Alternaria toxins (ATs) in solanaceous vegetables and their products with solid-phase extraction (SPE) and ultrahigh-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS). This study was the first to reveal that some compounds in the eggplant matrix bind to altenusin (ALS). Validation under optimal sample preparation conditions showed that the method met the EU criteria, exhibiting good linearity (R2 > 0.99), matrix effects (−66.6–−20.5%), satisfying recovery (72.0–107.4%), acceptable precision (1.5–15.5%), and satisfactory sensitivity (0.05–2 µg/kg for limit of detection, 2–5 µg/kg for limit of quantification). Out of 393 marketed samples, only 47 samples were detected, ranging from 0.54–806 μg/kg. Though the occurrence ratio (2.72%) in solanaceous vegetables could be negligible, the pollution status in solanaceous vegetable products was much more serious, and the incidences were 41.1%. In the 47 contaminated samples, the incidences were 4.26% for alternariol monomethyl ether (AME), 6.38% for alternariol (AOH) and altenuene (ALT), 42.6% for tentoxin (TEN), and 55.3% for tenuazonic acid (TeA).

Comprehensive review on patulin and Alternaria toxins in fruit and derived products

Mycotoxins are toxic secondary metabolites produced by certain fungi, which can contaminate various food commodities, including fruits and their derived products. Patulin and Alternaria toxins are among the most commonly encountered mycotoxins in fruit and their derived products. In this review, the sources, toxicity, and regulations related to these mycotoxins, as well as their detection and mitigation strategies are widely discussed. Patulin is a mycotoxin produced mainly by the fungal genera Penicillium, Aspergillus, and Byssochlamys. Alternaria toxins, produced by fungi in the Alternaria genus, are another common group of mycotoxins found in fruits and fruit products. The most prevalent Alternaria toxins are alternariol (AOH) and alternariol monomethyl ether (AME). These mycotoxins are of concern due to their potential negative effects on human health. Ingesting fruits contaminated with these mycotoxins can cause acute and chronic health problems. Detection of patulin and Alternaria toxins in fruit and their derived products can be challenging due to their low concentrations and the complexity of the food matrices. Common analytical methods, good agricultural practices, and contamination monitoring of these mycotoxins are important for safe consumption of fruits and derived products. And Future research will continue to explore new methods for detecting and managing these mycotoxins, with the ultimate goal of ensuring the safety and quality of fruits and derived product supply.

Cytotoxicities of Co-occurring alternariol, alternariol monomethyl ether and tenuazonic acid on human gastric epithelial cells

Alternariol (AOH), alternariol monomethyl ether (AME) and tenuazonic acid (TeA) are the three major Alternaria toxin contaminants in food. In the present study, we conducted their single and combined toxicity analyses using human gastric epithelial cell line (GES-1) that was first exposed to the toxins when they entered the human body. By comparing the cytotoxicity IC50, we found that compared to several other mycotoxins with limit standards there was cytotoxicity DON > OTA > AME > AOH > ZEN > TeA. Further, we obtained combination index (CI)-isobologram equation by the Chou-Talalay method according to a toxin ratio of 1:1:2 and carried out the combined toxicity analysis of the three binary and ternary compounds, and the results showed that AOH + AME + TeA showed synergistic toxic effects. Based on the co-occurring status, we also carried out the combined toxicity analysis of AME and AOH at different ratios and found antagonistic effects at low cytotoxic concentrations as well as synergistic and additive effects at high concentrations. Also, we found that all three and their combinations caused apoptosis, activation of caspase-3 cleavage, activation of DNA damage pathways ATR-Chk1-P53 and ATM-Chk2-P53. In conclusion, we used GES-1 cells to inform the risk of coaction of AOH, AME, and TeA in dietary exposure.

Occurrence and Determination of Alternaria Mycotoxins Alternariol, Alternariol Monomethyl Ether, and Tentoxin in Wheat Grains by QuEChERS Method

The Alternaria mycotoxins such as alternariol (AOH), alternariol monomethyl ether (AME), and tentoxin (TEN) are mycotoxins, which can contaminate cereal-based raw materials. Today, wheat is one of the most important crops in temperate zones, and it is in increasing demand in the Western Balkans countries that are urbanizing and industrializing. This research aimed to investigate the occurrence and determine the concentration of Alternaria mycotoxins AOH, AME, and TEN in wheat samples from the Republic of Serbia and the Republic of Albania, harvested in the year 2020 in the period between 15 June and 15 July. A total of 80 wheat grain samples, 40 from each country, were analyzed by an QuEChERS (quick, easy, cheap, effective, rugged, and safe) method. From the obtained results, it can be seen that the mean concentration of AOH was 3.3 µg/kg and AME was 2.2 µg/kg in wheat samples from Serbia, while TEN from both Serbia and Albania was under the limit of quantification (<LOQ). The maximum of AOH and AME mycotoxins was recorded only in wheat grain samples collected in the Republic of Serbia (5.3 and 2.3 µg/kg). In conclusion, Alternaria mycotoxins have concentrations above the LOQ, which could be potentially considered a health hazard to both humans and animals.

General toxicity and genotoxicity of alternariol: a novel 28-day multi-endpoint assessment in male Sprague-Dawley rats

Alternariol (AOH) is one of the toxins of Alternaria, and it has been widely detected in a variety of foods. It has been reported to be cytotoxic, dermally toxic, genotoxic, and potentially carcinogenic in vitro. However, in vivo toxicity data are lacking. This study used a novel in vivo 28-day multi-endpoint (Pig-a assay + micronucleus test + comet assay) genotoxicity evaluation system to evaluate the general toxicity and genotoxicity of AOH. A total of 42 male Sprague-Dawley rats were randomly distributed into three AOH-treated groups (5.51, 10.03, and 22.05 µg/kg bw), one AOH high-dose recovery group (AOH-HR, 22.05 µg/kg bw), one positive control group (N-ethyl-N-nitrosourea, 40 mg/kg bw), and two vehicle control groups (corn oil and PBS). Treatments were administered by oral gavage for 28 consecutive days. Histopathological lesions were observed in the liver, kidney, and spleen in all AOH-treated groups. No statistical difference was found in each genotoxicity index within 28 days in the AOH-treated groups compared with those in the corn oil group. On day 42, in the AOH-HR group, the rate of Pig-a mutant phenotype reticulocytes (RET^CD59-) significantly increased. On day 56, both RET^CD59- and the rate of Pig-a mutant phenotype erythrocytes (RBC^CD59-) were significantly reduced. These findings indicated that AOH might cumulatively induce genetic mutations.

Urinary analysis reveals high Alternaria mycotoxins exposure in the general population from Beijing, China

Alternaria mycotoxins are of concern due to its adverse health effect, they affect various cereal crops and grain-based food along with modified forms that contribute to overall exposure. This study aimed to determine the frequency and level of exposure to Alternaria mycotoxins (tenuazonic acid, TeA; alternariol, AOH; alternariol monomethyl ether, AME; tentoxin, TEN; and altenuene, ALT) in human urine from Beijing adults. A total of 2212 urine samples were collected and analyzed for five mycotoxins using LC-ESI-MS/MS. More than 98% of the samples had at least one Alternaria mycotoxin detected. Among the mycotoxins, AME had the highest detection rate (96.0%), followed by TeA (70.5%). The calculated average daily intake values of AME (12.5 ng/kg b.w.) was 5 times the TTC value (2.5 ng/kg b.w.) set by the EFSA, indicating the potential health risks associated with mycotoxins. Immediate attention and subsequent actions should be taken to identify the sources of mycotoxins and the corresponding exposure pathways to humans in the investigated regions.

Probabilistic Risk Assessment of Combined Exposure to Deoxynivalenol and Emerging Alternaria Toxins in Cereal-Based Food Products for Infants and Young Children in China

Deoxynivalenol (DON) and emerging Alternaria toxins often co-occur in cereal-based products, but the current risk assessment is commonly conducted for only one type of mycotoxin at a time. Compared to adults, infants and young children are more susceptible to mycotoxins through food consumption, especially with cereal-based food products which are the main source of exposure. This study aimed to perform a probabilistic risk assessment of combined exposure to DON and three major Alternaria toxins, namely including alternariol monomethyl ether (AME), alternariol (AOH), and tenuazonic acid (TeA) through consumption of cereal-based foods for Chinese infants and young children. A total of 872 cereal-based food products were randomly collected and tested for the occurrence of DON and three major Alternaria toxins. The results on mycotoxin occurrence showed the DON, TeA, AOH, and AME was detected in 56.4%, 47.5%, 7.5%, and 5.7% of the samples, respectively. Co-contamination of various mycotoxins was observed in 39.9% of the analyzed samples. A preliminary cumulative risk assessment using the models of hazard index (HI) and combined margin of exposure (MoET) was performed on DON and Alternaria toxins that were present in cereal-based food products for infants and young children in China for the first time. The results showed that only 0.2% and 1.5%, respectively, of individuals exceeded the corresponding reference value for DON and TeA, indicating a low health risk. However, in the case of AME and AOH, the proportion of individuals exceeding the reference value was 24.1% and 33.5%, respectively, indicating the potential health risks. In the cumulative risk assessment of AME and AOH, both HI and MoET values indicated a more serious risk than that related to individual exposure. Further research is necessary to reduce the uncertainties that are associated with the toxicities of the Alternaria toxins and cumulative risk assessment methods.

Aptasensor Based on Microfluidic for Foodborne Pathogenic Bacteria and Virus Detection: A Review

In today's world, which is entangled with numerous foodborne pathogenic bacteria and viruses, it appears to be essential to rethink detection methods of these due to the importance of food safety in our lives. The vast majority of detection methods for foodborne pathogenic bacteria and viruses have suffered from sensitivity and selectivity due to the small size of these pathogens. Besides, these types of sensing approaches can improve on-site detection platforms in the fields of food safety. In recent, microfluidics systems as new emerging types of portable sensing approaches can introduce efficient and simple biodevice by integration with several analytical methods such as electrochemical, optical and colorimetric techniques. Additionally, taking advantage of aptamer as a selective bioreceptor in the sensing of microfluidics system has provided selective, sensitive, portable and affordable sensing approaches. Furthermore, some papers use increased data transferability ability and computational power of these sensing platforms by exploiting smartphones. In this review, we attempted to provide an overview of the current state of the recent aptasensor based on microfluidic for screening of foodborne pathogenic bacteria and viruses. Working strategies, benefits and disadvantages of these sensing approaches are briefly discussed.

Contamination, Detection and Control of Mycotoxins in Fruits and Vegetables

Mycotoxins are secondary metabolites produced by pathogenic fungi that colonize fruits and vegetables either during harvesting or during storage. Mycotoxin contamination in fruits and vegetables has been a major problem worldwide, which poses a serious threat to human and animal health through the food chain. This review systematically describes the major mycotoxigenic fungi and the produced mycotoxins in fruits and vegetables, analyzes recent mycotoxin detection technologies including chromatography coupled with detector (i.e., mass, ultraviolet, fluorescence, etc.) technology, electrochemical biosensors technology and immunological techniques, as well as summarizes the degradation and detoxification technologies of mycotoxins in fruits and vegetables, including physical, chemical and biological methods. The future prospect is also proposed to provide an overview and suggestions for future mycotoxin research directions.

Determination of Alternaria Toxins in Food by SPE and LC-IDMS: Development and In-House Validation of a Candidate Method for Standardisation

Alternaria toxins (ATs) are frequently found contaminants in foodstuffs (e.g., alternariol), often reaching high concentrations (e.g., tenuazonic acid). They can spoil a wide variety of food categories (e.g., cereals, vegetables, seeds and drinks) and storage at fridge temperatures does not prevent the growth of Alternaria fungi. Therefore, reliable and validated analytical methods are needed to protect human health and to ensure a transparent and fair trade. This paper describes new technical features that improved a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the analysis of ATs in tomato, wheat and sunflower seeds. This analytical method should be simple to implement in different laboratories across the EU and thus be an attractive candidate for standardisation. The major element for improvement was the use of isotopically labelled internal standards, only recently commercially available, thereby reducing the sample handling and improving the accuracy of the results. In addition, the sample extraction and the solid-phase extraction (SPE) enrichment/clean-up were fine-tuned, whereas a more suitable analytical column (XSelect HSS T3) with improved selectivity was also employed. Overall, this method shows adequate precision (repeatability < 5.7% RSD; intermediate precision < 7.0% RSD) and trueness (recoveries ranging from 74% to 112%). The limits of quantification in wheat (the most analytically demanding matrix) vary between 0.19 and 1.40 µg/kg. These figures were deemed satisfactory by the European Committee for Standardization (CEN) and have formed the basis for a subsequent interlaboratory validation study. The corresponding standard was published by CEN in 2021.

Detection of Mycotoxins in Highly Matrix-Loaded House-Dust Samples by QTOF-HRMS, IM-QTOF-HRMS, and TQMS: Advantages and Disadvantages

The analysis of (trace) contaminants in environmental samples represents an important tool for exposure assessment and for the evaluation of potential risks to human health. Currently, mass spectrometric detection using triple quadrupole (TQMS) systems is the established method of choice. However, screening methods using high resolution mass spectrometry (HRMS) find increasing application as they provide advantages such as enhanced selectivity. A complex composition of environmental samples is known to have enormous effects on mass analyzers. The present work therefore compares the impact of a highly matrix-loaded sample material like house-dust on the performance of mass spectrometric detection of the emerging indoor contaminant group of mycotoxins by quadrupole time-of-flight (QTOF) and TQMS after ultrahigh-performance liquid chromatographic separation. Furthermore, the role of ionization efficiencies of different ion sources in instrument sensitivity was compared using an electrospray ionization source and a newly developed heated electrospray ion source (Bruker VIP-HESI) during QTOF experiments. Finally, it was evaluated whether an additional dimension of separation enables increased sensitivity in QTOF-HRMS detection by applying mycotoxins in house-dust to an (trapped) ion mobility spectrometry instrument. The sensitivity of the QTOF detection was positively influenced by the application of the VIP-HESI ion source, and overall HRMS instruments provided enhanced selectivity resulting in simplified data evaluation compared to the TQMS. However, all performed experiments revealed strong signal suppression due to matrix components. QTOF results showed more severe effects, enabling a more sensitive detection of mycotoxins in house-dust by applying TQMS detection.

Monitoring Alternaria toxins in Italian food to support upcoming regulation

The collection of occurrence data on Alternaria toxins in food and feed across the European countries is required since 2012 by the European Commission, endorsing the relevant scientific opinion by the EFSA CONTAM Panel. Within this framework, occurrence data for Alternaria toxins (Alternariol, Alternariol monomethyl ether, Tenuazonic acid, Tentoxin, and Altenuene) in 97 samples of cereal foods, tomato products, and sunflower seeds have been provided as requested by the Italian national monitoring programme (years 2017-2020). To this purpose, an LC-MS/MS method was set up and validated, obtaining fit for purpose sensitivity, recoveries (70-120%), repeatability (≤20%) and within laboratory reproducibility (≤26%). Occurrence data showed that oilseeds were the most contaminated food group with levels of Tenuazonic acid up to 16752 µg/kg and Tentoxin up to 570 µg/kg, whereas for the other mycotoxin/commodities combinations, the percentage of left censored data (below the limit of quantification) ranged from 74 to 100%.

Postharvest UV-C irradiation inhibits blackhead disease by inducing disease resistance and reducing mycotoxin production in 'Korla' fragrant pear (Pyrus sinkiangensis)

Blackhead disease is a major fungal disease causing the quality deterioration of postharvest 'Korla' fragrant pear. In this study, the relationships of resistance to blackhead disease with the enzyme activity, phenolic compounds, and mycotoxin metabolism of 'Korla' fragrant pear were investigated, through UV-C irradiation of 0.12, 0.24, 0.36, 0.48, 0.72 and 1.08 kJ/m² on 'Korla' fragrant pear inoculated with Alternaria alternata (Fries) Keissler (A. alternata). The results showed that the low-dose UV-C irradiation (0.36 kJ/m²) effectively controlled blackhead disease. The activities of chitinase (CHI), β-1,3-glucanase (GLU), peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), phenylalanine ammonia-lyase (PAL), and the content of phenolic compounds in fruit were enhanced, whereas the activities of lipoxygenase (LOX), polyphenol oxidase (PPO), and the contents of hydrogen peroxide (H₂O₂) and mycotoxins (including AOH, AME, and TeA) were decreased. Therefore, the low-dose UV-C irradiation could improve the resistance to blackhead disease and reduce the production of mycotoxins in 'Korla' fragrant pear. This study proves that UV-C irradiation may be a potentially effective strategy for the control of blackhead disease and the improvement of quality of postharvest 'Korla' fragrant pear.

Non-embryotoxic dosage of alternariol aggravates ochratoxin A-triggered deleterious effects on embryonic development through ROS-dependent apoptotic processes

Alternariol (AOH) and ochratoxin A (OTA), two mycotoxins found in many foods worldwide, exhibit cytotoxicity and embryotoxicity, triggering apoptosis and cell cycle arrest in several mammalian cells and mouse embryos. The absorption rate of AOH from dietary foodstuff is low, meaning that the amount of AOH obtained from the diet rarely approaches the cytotoxic threshold. Thus, the potential harm of dietary consumption of AOH is generally neglected. However, previous findings from our group and others led us to question whether a low dosage of AOH could aggravate the cytotoxicity of other mycotoxins. In the present study, we examined how low dosages of AOH affected OTA-triggered apoptosis and embryotoxicity and investigated the underlying regulatory mechanism in mouse blastocysts. Our results revealed that non-cytotoxic concentrations of AOH (1 and 2 μM) could enhance OTA (8 μM)-triggered apoptotic processes and embryotoxicity in mouse blastocysts. We also found that AOH can enhance OTA-evoked intracellular reactive oxygen species (ROS) generation and that this could be prevented by pretreatment with the potent ROS scavenger, N-acetylcysteine. Finally, we observed that this ROS generation acts as a key inducer of caspase-dependent apoptotic processes and subsequent impairments of embryo implantation and pre- and post-implantation embryonic development. In sum, our results show that non-cytotoxic dosages of AOH can aggravate OTA-triggered apoptosis and embryotoxicity through ROS- and caspase-dependent signaling pathways.

Assessment of the Optimum Linker Tethering Site of Alternariol Haptens for Antibody Generation and Immunoassay Development

Immunochemical methods for mycotoxin analysis require antigens with well-defined structures and antibodies with outstanding binding properties. Immunoreagents for the mycotoxins alternariol and/or alternariol monomethyl ether have typically been obtained with chemically uncharacterized haptens, and antigen conjugates have most likely been prepared with mixtures of functionalized molecules. For the first time, total synthesis was performed, in the present study, to obtain two haptens with opposite linker attachment locations. The functionalized synthetic haptens were purified and deeply characterized by different spectrometric methods, allowing the preparation of bioconjugates with unequivocal structures. Direct and indirect competitive enzyme-linked immunosorbent assays, using homologous and heterologous conjugates, were employed to extensively evaluate the generated immunoreagents. Antibodies with high affinity were raised from conjugates of both haptens, and a structure-activity relationship between the synthetic haptens and the specificity of the generated antibodies could be established. These results pave the way for the development of novel highly sensitive immunoassays selective of one or two of these Alternaria mycotoxins.

Alternariol exerts embryotoxic and immunotoxic effects on mouse blastocysts through ROS-mediated apoptotic processes

Alternariol (AOH), a mycotoxin belonging to the genus Alternaria, has been shown to induce cytotoxicity, including apoptosis and cell cycle arrest, in several mammalian cell types. However, its effects on early-stage embryonic development require further investigation. Here, we have shown that AOH exerts embryotoxic effects on mouse blastocyst-stage embryos and long-term adverse effects on immunity in one-day-old newborn mice of the next generation. Significant apoptosis and decrease in total cell number, predominantly through loss of inner cell mass (ICM), and to a minor extent, trophectoderm (TE) cells, were observed in AOH-treated blastocysts. Moreover, AOH exerted detrimental effects on pre- and post-implantation embryo development potential and induced a decrease in fetal weight in in vitro development and embryo transfer assays. Injection of pregnant mice with AOH (1, 3 and 5 mg/kg body weight/day) for 4 days resulted in apoptosis of blastocyst-stage embryos and injurious effects on embryonic development from the zygote to blastocyst stage or embryo degradation and a further decrease in fetal weight. Furthermore, AOH exerted a long-term impact on the next generation, triggering a significant increase in total oxidative stress content and expression of genes encoding antioxidant proteins. Lower expression of CXCL1, IL-1β and IL-8 related to innate immunity was detected in liver tissue extracts obtained from one-day-old newborns of AOH-injected pregnant mice (5 mg/kg body weight/day) relative to their non-treated counterparts. In addition, ROS served as an upstream regulator of AOH-triggered apoptotic processes and impairment of embryonic development. Our collective results highlight the potential of AOH as an embryotoxic and immunotoxic risk factor during embryo and infant development stages in mice.

Alternaria toxins-Still emerging?

Alternaria molds are known to cause the contamination of food with their secondary metabolites, a chemically very heterogeneous group of compounds. Yet, after decades of research on the occurrence and the toxicity of Alternaria toxins in academia, no regulation has been implemented yet, thus leaving these potential food contaminants in the status of so-called "emerging mycotoxins". However, research on this topic has been far from static, leading to the European Food Safety Authority repeatedly calling for more data on the occurrence and toxicity of genotoxic metabolites such as alternariol (AOH) and its monomethyl ether (AME). To give an overview on recent developments in the field, this comprehensive review summarizes published data and addresses current challenges arising from the chemical complexity of Alternaria's metabolome, mixture effects and the emergence of novel biological targets like cell membranes or the interaction with different receptors. Besides toxicodynamics, we review recent research on toxicokinetics, including the first in vivo studies which incorporated the rarely investigated-but highly genotoxic-perylene quinones. Furthermore, a particular focus lies on the advances of liquid chromatography/tandem mass spectrometry (LC-MS/MS)-based analytical tools for determining a broader spectrum of Alternaria toxins including modified/masked forms and assessing exposure via human biomonitoring (HBM).

Determination of Alternaria toxins in tomato, wheat and sunflower seeds by SPE and LC-MS/MS - a method validation through a collaborative trial

Background

Alternaria toxins are ubiquitous contaminants in highly consumed food products. Therefore, they are candidates to be regulated by EU legislation. In this context, the availability of reliable analytical methods is a keystone both for protecting the health of citizens and smooth functioning of the European market.

Objective

This paper describes an advanced LC-MS/MS method based on isotope dilution quantification suitable for the determination of altenuene, alternariol, alternariol monomethyl ether, tenuazonic acid, and tentoxin in tomato puree, wheat, and sunflower seeds.

Methods

The method has been validated in an interlaboratory study that included the analysis of both spiked and naturally contaminated food commodities. Twenty-three participants contributed with analytical data.

Results

The average recoveries and relative standard deviations for repeatability and reproducibility obtained across the tested matrixes were: 97, 8.0, and 23%, for altenuene, respectively; 95, 9.2, and 17% for alternariol, respectively; 98, 6.4, and 13% for alternariol monomethyl ether, respectively; 97, 4.2, and 9.3% for tenuazonic acid, respectively; and 102, 5.6, and 15% for tentoxin, respectively. The method enabled the determination of all tested Alternaria toxins close to or below 1 µg/kg.

Conclusion

Overall, the method showed a satisfactory trueness and precision, complying with the requirements for the monitoring of mycotoxins in food in the EU. It is currently under evaluation by the European Committee for Standardization for adoption as a standard method.

Highlights

Isotope dilution mass spectrometry method for the determination of Alternaria toxins in food.

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.

Determination of Urinary Mycotoxin Biomarkers Using a Sensitive Online Solid Phase Extraction-UHPLC-MS/MS Method

In the course of assessing the human exposure to mycotoxins, biomarker-based approaches have proven to be important tools. Low concentration levels, complex matrix compositions, structurally diverse analytes, and the large size of sample cohorts are the main challenges of analytical procedures. For that reason, an online solid phase extraction-ultra high-performance liquid chromatography-tandem mass spectrometry (online SPE-UHPLC-MS/MS) method was developed, allowing for the sensitive, robust, and rapid analysis of 11 relevant mycotoxins and mycotoxin metabolites in human urine. The included spectrum of analytes comprises aflatoxin M₁ (AFM₁), altenuene (ALT), alternariol monomethyl ether (AME), alternariol (AOH), citrinin (CIT) and its metabolite dihydrocitrinone (DH-CIT), fumonisin B₁ (FB₁), ochratoxin A (OTA), and zearalenone (ZEN) as well as α- and β-zearalenol (α- and β-ZEL). Reliable quantitation was achieved by means of stable isotope dilution, except for ALT, AME and AOH using matrix calibrations. The evaluation of method performance displayed low limits of detection in the range of pg/mL urine, satisfactory apparent recovery rates as well as high accuracy and precision during intra- and interday repeatability. Within the analysis of Zimbabwean urine samples (n = 50), the applicability of the newly developed method was shown. In addition to FB₁ being quantifiable in all analyzed samples, six other mycotoxin biomarkers were detected. Compared to the occurrence rates obtained after analyzing the same sample set using an established dilute and shoot (DaS) approach, a considerably higher number of positive samples was observed when applying the online SPE method. Owing to the increased sensitivity, less need of sample handling, and low time effort, the herein presented online SPE approach provides a valuable contribution to human biomonitoring of mycotoxin exposure.

Alternaria toxins in tomato products in Northern Italy in the period 2017-2019

The occurrence of tenuazonic acid (TeA), alternariol, alternariol monomethyl and tentoxin in tomato-based products was surveyed over the years 2017-2019. A total of 120 samples were collected from retail outlets and tomato-based food producers located in Northern Italy. After extraction and purification through prepacked columns, the mycotoxins were analysed using LC-MS/MS. A widespread contamination of TeA was found in tomato-based products, particularly in concentrated tomato paste. Other Alternaria toxins were not detected. The incidence of TeA was 78.5%, 47.4%, 55.5%, and 76.9% in concentrated tomato paste (maximum value 5955 µg kg^-1), tomato sauce, tomato pulp, and ketchup, respectively. The mean level was 243 ± 725 µg kg^-1 in concentrated tomato paste and below 30 µg kg^-1 in the other tomato products. The contamination varied from year to year. Alternaria spp strains isolated from fresh tomatoes produced mainly TeA. This study provides further Alternaria toxins occurrence data, useful for future risk assessments.

Enhanced Non-Toxic Immunodetection of Alternaria Mycotoxin Tenuazonic Acid Based on Ferritin-Displayed Anti-Idiotypic Nanobody-Nanoluciferase Multimers

The non-toxic immunoassay for mycotoxins is being paid more attention due to its advantages of higher safety and cost savings by using anti-idiotype antibodies to substitute toxins. In this study, with tenuazonic acid (TeA), a kind of highly toxic Alternaria mycotoxin as the target, an enhanced non-toxic immunoassay was developed based on the ferritin-displayed anti-idiotypic nanobody-nanoluciferase multimers. First, three specific β-type anti-idiotype nanobodies (AId-Nbs) bearing the internal image of TeA mycotoxin were selected from an immune phage display library. Then, the AId-Nb 2D with the best performance was exploited to generate a nanoluciferase (Nluc)-functionalized fusion monomer, by which a one-step non-toxic immunodetection format for TeA was established and proven to be effective. To further improve the affinity of the monomer, a ferritin display strategy was used to prepare 2D-Nluc fusion multimers. Finally, an enhanced bioluminescent enzyme immunoassay (BLEIA) was established in which the half maximal inhibitory concentration (IC₅₀) for TeA was 6.5 ng/mL with a 10.5-fold improvement of the 2D-based enzyme-linked immunosorbent assay (ELISA). The proposed assay exhibited high selectivities and good recoveries of 80.0-95.2%. The generated AId-Nb and ferritin-displayed AId-Nb-Nluc multimers were successfully extended to the application of TeA in food samples. This study brings a new strategy for production of multivalent AId-Nbs and non-toxic immunoassays for trace toxic contaminants.

Characterization of Alternaria Species Associated with Heart Rot of Pomegranate Fruit

This study was aimed at identifying Alternaria species associated with heart rot disease of pomegranate fruit in southern Italy and characterizing their mycotoxigenic profile. A total of 42 Alternaria isolates were characterized. They were obtained from pomegranate fruits with symptoms of heart rot sampled in Apulia and Sicily and grouped into six distinct morphotypes based on macro- and microscopic features. According to multigene phylogenetic analysis, including internal transcribed spacer (ITS), translation elongation factor 1-α (EF-1α), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and a SCAR marker (OPA10-2), 38 isolates of morphotypes 1 to 5 were identified as Alternaria alternata, while isolates of morphotype 6, all from Sicily, clustered within the Alternaria arborescens species complex. In particular, isolates of morphotype 1, the most numerous, clustered with the ex-type isolate of A. alternata, proving to belong to A. alternata. No difference in pathogenicity on pomegranate fruits was found between isolates of A. alternata and A. arborescens and among A. alternata isolates of different morphotypes. The toxigenic profile of isolates varied greatly: in vitro, all 42 isolates produced tenuazonic acid and most of them other mycotoxins, including alternariol, alternariol monomethyl ether, altenuene and tentoxin.

A Dilute and Shoot Strategy for Determining Alternaria Toxins in Tomato-Based Samples and in Different Flours Using LC-IDMS Separation

Alternaria toxins are emerging mycotoxins whose regulation and standardization are in progress by the European Commission and the European Committee for Standardization. This paper describes a dilute and shoot approach to determine five Alternaria toxins in selected food samples using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The strategy involves sample extraction with acidified aqueous methanol, followed by a solvent change accomplished via sample evaporation and reconstitution. The quantification is based on isotope dilution, applying all corresponding isotopically labeled internal standards to compensate possible matrix effects of the analysis. The main advantages of the present method over other existing methods includes simple and effective sample preparation, as well as detection with high sensitivity. The five-fold sample dilution can decrease matrix effects, which were evaluated with both external and internal standard methods. The results demonstrated a limit of quantification lower than 1.0 µg/kg for all five analytes for the first time. The newly presented method showed acceptable accuracy (52.7-111%) when analyzing naturally contaminated and spiked standard samples at the described levels. The method was validated for tomato-based and flour samples (wheat, rye, and maize). The absolute recovery ranged from 66.7% to 91.6% (RSD < 10%). The developed method could be an alternative approach for those laboratories that exclude sample cleanup and pre-concentration of state-of-the-art instruments with enhanced sensitivity.

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.

Applications of surface functionalized Fe3O4 NPs-based detection methods in food safety

Food safety has always been an issue of great concern to people. The development of rapid, sensitive and specific detection technology of food pollutants is one of the hot issues in food science field. The rapid development of functionalized Fe₃O₄ nanoparticles (NPs) provides unprecedented opportunities and technical support for the innovation of food safety detection. The surface functionalized Fe₃O₄ NPs, which combine superparamagnetic with nanoscale feature, have become an excellent tool for food quality and safety detection. This review highlights the mechanism, principles, and applications of surface functionalized Fe₃O₄ NPs-based detection technique in the agrifood industry. Then the relevant characteristics, functional roles and general mechanisms of nanomaterial-based detection of various endogenous components and exogenous pollutants in foods are discussed in detail. Ultimately, this review is expected to promote the optimization of functionalized Fe₃O₄ NPs and provide direction for the diversity of signal recognition and the sustainability of detection methods.

Quantification of multi-mycotoxin in cereals (maize, maize porridge, sorghum and wheat) from Limpopo province of South Africa

Mycotoxins are secondary metabolites that are produced by filamentous mycotoxigenic fungi belonging to the Alternaria, Aspergillus, Fusarium and Penicillium genera amongst others. Multi-class mycotoxins were extracted from 55 cereal samples and analysed using liquid chromatography-tandem mass spectrometry. The adopted extraction method for maize, maize porridge, sorghum and wheat was comprehensively validated. This method was further tested to determine the natural occurrence of mycotoxins in foodstuffs. Twelve (12) out of 22 mycotoxins were detected in maize, maize porridge, sorghum and wheat, including α-zearalenol (α-ZEL) (89%), fumonisin B₃ (FB₃) (84%), fumonisin B₁ (FB₁) (80%), tenuazonic acid (TeA) (78%), ochratoxin B (42%), deoxynivalenol (DON) (12%), ochratoxin A (11%), 3-acetyldeoxynivalenol (7%), sterigmatocystin (STG) (6%), 15-acetyldeoxynivalenol (2%), cyclopiazonic acid (CPA) (2%) and aflatoxin B₂ (2%). The data revealed high incidence rate of α-ZEL (range: 6.5-70.5 µg kg^-1) in all matrices. Maize samples had high mycotoxin co-occurrence compared to other matrices. All recovered mycotoxins in food commodities were within the maximum regulatory limits, with the exception of fumonisins (FB₁ and FB₃) exceeded the South African and European Commission regulation, and the highest concentration was 2153 µg kg^-1 in maize. It is essential to monitor the level of emerging mycotoxins in food commodities from rural areas as trace amount of CPA (< limit of quantification), STG (range: 0.30-0.74 µg kg^-1) were detected and high concentration of TeA (292.7 µg kg^-1) was detected in sorghum. The occurrence of these mycotoxins further encourages frequent analyses, their co-occurrence in the samples poses a significant threat to public health and more emphasis should thus be placed on reducing the contamination levels of these toxins in staples.

Alternaria alternata Toxins Synergistically Activate the Aryl Hydrocarbon Receptor Pathway In Vitro

Alternaria molds simultaneously produce a large variety of mycotoxins, of which several were previously reported to induce enzymes of phase I metabolism through aryl hydrocarbon receptor activation. Thus, we investigated the potential of naturally occurring Alternaria toxin mixtures to induce Cytochrome P450 (CYP) 1A1/1A2/1B1 activity. Two variants of an extract from cultured Alternaria alternata, as well as the toxins alternariol (AOH), alternariol monomethyl ether (AME), altertoxin I (ATX-I), and altertoxin II (ATX-II), were tested singularly and in binary mixtures applying the 7-ethoxy-resorufin-O-deethylase (EROD) assay in MCF-7 breast cancer cells. Sub-cytotoxic concentrations of the two toxin mixtures, as well as ATX-I, ATX-II and AOH, exhibited dose-dependent enhancements of CYP 1 activity. ATX-I and ATX-II interacted synergistically in this respect, demonstrating the two perylene quinones as major contributors to the extract’s potential. Binary mixtures between AOH and the two altertoxins respectively exhibited concentration-dependent antagonistic as well as synergistic combinatory effects. Notably, AME showed no efficacy towards EROD enzyme activity or impact on other toxins’ efficacy. Hence, this study provides insights into synergistic and other combinatory effects of Alternaria toxins in natural co-occurrence scenarios in the context of AhR signalling pathway activation in breast cancer cells.

Determination of Alternaria Toxins in Sunflower Oil by Liquid Chromatography Isotope Dilution Tandem Mass Spectrometry

Alternaria toxins have gained attention as a potential health risk and can be classified as emerging mycotoxins. As a result, they are candidates to be regulated by the European Commission. This paper describes a liquid chromatography tandem mass spectrometric (LC-MS/MS) method for analyzing five Alternaria toxins in sunflower oil, which is a rather different type of sample to those matrices investigated in earlier published papers. An optimal sample preparation condition was achieved when samples were dissolved in n-hexane and extracted with methanol/water mixture, followed by sample pre-concentration with solvent evaporation. This study is the first focusing only on this lipophilic matrix and in using all corresponding isotopically labeled internal standards (ISTD) to compensate the matrix effect that strongly influences the LC-MS/MS analysis of toxins. Target compounds were separated on Zorbax Extend C-18 column enabling the analysis at alkaline pH of 8.8 that was necessary to obtain appropriate peak shape of tenuazonic acid and to separate the analytes at baseline. The method was validated according to the EU 2002/657/EC Decision and all the analytical performance characteristics met the requirements. The recovery was between 74% and 122% in fortified sunflower oil samples and the precision varied from 9% to 22%. The method was successfully demonstrated for sunflower seed quality check (QC) samples. Finally, 16 different sunflower oil samples were measured; and tenuazonic acid and tentoxin toxins were detected at levels close to LOQ concentrations.

First Synthesis of (-)-Altenuene-D3 Suitable as Internal Standard for Isotope Dilution Mass Spectrometry

Metabolites from Alternaria fungi exhibit a variety of biological properties such as phytotoxic, cytotoxic, or antimicrobial activity. Optimization of a literature procedure culminated in an efficient total synthesis of (-)-altenuene as well as a stable isotope-labeled derivative suitable for implementation in a LC-MS/MS method for mycotoxin analysis.

Co-Occurrence and Combinatory Effects of Alternaria Mycotoxins and other Xenobiotics of Food Origin: Current Scenario and Future Perspectives

Mycotoxins are low-molecular weight compounds produced by diverse genera of molds that may contaminate food and feed threatening the health of humans and animals. Recent findings underline the importance of studying the combined occurrence of multiple mycotoxins and the relevance of assessing the toxicity their simultaneous exposure may cause in living organisms. In this context, for the first time, this work has critically reviewed the most relevant data concerning the occurrence and toxicity of mycotoxins produced by Alternaria spp., which are among the most important emerging risks to be assessed in food safety, alone or in combination with other mycotoxins and bioactive food constituents. According to the literature covered, multiple Alternaria mycotoxins may often occur simultaneously in contaminated food, along with several other mycotoxins and food bioactives inherently present in the studied matrices. Although the toxicity of combinations naturally found in food has been rarely assessed experimentally, the data collected so far, clearly point out that chemical mixtures may differ in their toxicity compared to the effect of toxins tested individually. The data presented here may provide a solid foothold to better support the risk assessment of Alternaria mycotoxins highlighting the actual role of chemical mixtures on influencing their toxicity.

A microfluidic colorimetric immunoassay for sensitive detection of altenariol monomethyl ether by UV spectroscopy and smart phone imaging

A novel microfluidic colorimetric immunoassay was developed using gold nanoparticles (GNPs) for indicating different concentrations of altenariol monomethyl ether (AME), and UV spectroscopy and smart phone imaging for monitoring color change of the GNPs. Norland Optical Adhesive 81 (NOA 81) was used for simple and rapid fabrication of the microfluidic chip. AME-BSA modified magnetic nanoparticles (MNPs-BSA-AME) were used as capture probe and the self-magnetism for rapid separation and purification. AME monoclonal antibodies modified gold nanoparticles (GNP-mAbs) which dried on conjugate pad were used as detection probe and the self-catalyst for signal amplification. Under the optimal conditions, the proposed microfluidic colorimetric immunoassay was able to detect AME as low as 12.5 pg/mL for UV spectroscopy (574 nm), and 200 pg/mL for smart phone imaging. The total analysis time is less than 15 min. The immunoassay also has a lower cross-reactivity to AME analogues. It was also evaluated by analyzing fruit samples spiked with AME. The recoveries ranged from 91.19% to 94.15% for UV spectroscopy, and from 90.63% to 93.9% for smart phone imaging. This method can be used for rapid, sensitive, low-cost and portable point-of care testing (POCT) of other mycotoxins or haptens in food samples.

Alternariol disturbs oocyte maturation and preimplantation development

Alternariol (AOH) is produced by fungi of the genus Alternaria and can be found in fruits, vegetables, and grains. Besides the oestrogenic activity demonstrated in vitro, this mycotoxin causes DNA damage and cell cycle arrest. Based on this, the effect of AOH was investigated on porcine female gametes during in vitro maturation and subsequent initial embryo development. A first experiment assessed a dose-response effect of AOH (5, 10, or 20 μmol/l) on cumulus expansion and in vitro oocyte nuclear maturation, in the presence or absence of follicular fluid (FF). A second experiment evaluated the effect of AOH (5, 10, or 20 μmol/l) exposure during porcine oocyte maturation, initial embryo development, or both periods, on preimplantation embryo development. Although FF protected oocytes from the deleterious effect of AOH, it did not avoid a decrease in cumulus cells expansion (5 μmol/l AOH regardless of the presence of FF). Moreover, exposure to AOH resulted in the degeneration of oocytes (10 μmol/l AOH in the absence of FF) and the occurrence of nuclear aberrations in mature oocytes (10 μmol/l AOH in the absence of FF and 20 μmol/l AOH in the presence of FF). Exposure to 5 μmol/l AOH during oocyte in vitro maturation was sufficient to impair initial embryo development.

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.