Potential Mycotoxin Research Articles

Investigation of fungal contamination in medicinal and edible Lycii Fructus through DNA metabarcoding

Lycii Fructus (LF) is considered as a 'superfood' due to its health benefits and delicious tastes, which has gained popularity worldwide. However, LF is also a proper host for fungal growth due to its abundant nutrients. Fungal contamination seriously affects the quality and safety of LF and poses threats to consumer health. In this study, a total of 15 LF samples were collected from five provinces in China, and were divided into five groups based on the collection areas. Fungal contamination in LF was investigated by targeting the internal transcribed spacer 2 region using Illumina Miseq PE300 platform, and the differences of fungal community in groups based on collection areas were compared. Results showed that the fungal contamination was detected in all the 15 LF samples. Ascomycota, Dothideomycetes, Pleosporales and Pleosporaceae were dominant at the phylum, class, order and family levels, respectively. At the genus level, Alternaria, Cladosporium and Fusarium were the three dominant genera. In all, 24 fungal species were identified. Among which, two species, namely Penicillium oxalicum and Trichothecium roseum, were potentially toxigenic. All 15 LF samples were detected with fungal contamination. The differences of fungal community in LF samples collected from different areas were observed. DNA metabarcoding was demonstrated as an efficient method to monitor the fungal contamination in LF. This work comprehensively reveals the fungal diversity and composition in LF and provides early warning for potential mycotoxin contamination.

Mycofloral diversity of glutinous rice Aghoni Bora in storage condition

Rice grain is contaminated with various fungi depending on the storage condition. The present study was conducted to identify the possible contaminants of glutinous rice variety Aghoni bora. Aghoni Bora grain samples were collected from districts of Assam. Nine species of filamentous fungi from the genus Acremonium, Aspergillus, Chaetomium, Cladosporium, Gibellula, Paecilomyces and Penicillium were identified morphologically among which potential mycotoxin producers were also present.

Mycotoxins in Tea ((Camellia sinensis (L.) Kuntze)): Contamination and Dietary Exposure Profiling in the Chinese Population.

Tea is popular worldwide with multiple health benefits. It may be contaminated by the accidental introduction of toxigenic fungi during production and storage. The present study focuses on potential mycotoxin contamination in tea and the probable dietary exposure assessments associated with consumption. The contamination levels for 16 mycotoxins in 352 Chinese tea samples were determined by ultra-performance liquid chromatography–tandem mass spectrometry. Average concentrations of almost all mycotoxins in tea samples were below the established regulations, except for ochratoxin A in the dark tea samples. A risk assessment was performed for the worst-case scenarios by point evaluation and Monte Carlo assessment model using the obtained mycotoxin levels and the available green, oolong, black, and dark tea consumption data from cities in China. Additionally, we discuss dietary risk through tea consumption as beverages and dietary supplements. In conclusion, there is no dietary risk of exposure to mycotoxins through tea consumption in the Chinese population.

Phylogenetic Diversity and Mycotoxin Potential of Emergent Phytopathogens Within the Fusarium tricinctum Species Complex.

Recent studies on multiple continents indicate members of the Fusarium tricinctum species complex (FTSC) are emerging as prevalent pathogens of small-grain cereals, pulses, and other economically important crops. These understudied fusaria produce structurally diverse mycotoxins, among which enniatins (ENNs) and moniliformin (MON) are the most frequent and of greatest concern to food and feed safety. Herein a large survey of fusaria in the Fusarium Research Center and Agricultural Research Service culture collections was undertaken to assess species diversity and mycotoxin potential within the FTSC. A 151-strain collection originating from diverse hosts and substrates from different agroclimatic regions throughout the world was selected from 460 FTSC strains to represent the breadth of FTSC phylogenetic diversity. Evolutionary relationships inferred from a five-locus dataset, using maximum likelihood and parsimony, resolved the 151 strains as 24 phylogenetically distinct species, including nine that are new to science. Of the five genes analyzed, nearly full-length phosphate permease sequences contained the most phylogenetically informative characters, establishing its suitability for species-level phylogenetics within the FTSC. Fifteen of the species produced ENNs, MON, the sphingosine analog 2-amino-14,16-dimethyloctadecan-3-ol (AOD), and the toxic pigment aurofusarin (AUR) on a cracked corn kernel substrate. Interestingly, the five earliest diverging species in the FTSC phylogeny (i.e., F. iranicum, F. flocciferum, F. torulosum, and Fusarium spp. FTSC 8 and 24) failed to produce AOD and MON, but synthesized ENNs and/or AUR. Moreover, our reassessment of nine published phylogenetic studies on the FTSC identified 11 additional novel taxa, suggesting this complex comprises at least 36 species.

Incidence of toxigenicAspergillus andFusarium species occurring in maize kernels from Kenyan households

Aspergillus andFusarium are fungal genera that include toxigenic and pathogenic species, able to suffuse farmers’ crops and secrete an array of small molecular weight secondary metabolites which can cause health complications to humans and animals when ingested. In sub-Sahara Africa, contamination and persistence of these fungi is increased by the tropical climatic conditions which are ideal for the fungi to thrive. This study evaluated the incidence, regional distribution and toxigenic potential ofAspergillus andFusarium species occurring in maize kernels from Eastern, Western, Coastal and the Lake Victoria agro-ecological zones of Kenya. Maize kernels were collected from 16 households in each agro-ecological zone. Single spore technique was used to isolate pure cultures ofAspergillus andFusarium which were identified morphologically. Further, molecular analysis was done using the internal transcribed spacer 1 (ITS 1) region of the ribosomal DNA forAspergillus and the translation elongation factor-1 alpha (TEF-1α) forFusarium. The potential of the isolated fungi to produce mycotoxins was probed by polymerase chain reaction (PCR) based on the aflatoxin regulatoryaflaR gene inAspergillus, and the fumonisin backbone structure geneFUM1 inFusarium. Among the potentially aflatoxigenicA. flavus species isolated, 55% were from Eastern, 27% from the Coastal zone, 13% from Lake Victoria zone and 5% from Western Kenya. Among the potentially fumonisin producingF. verticillioides isolated, 45% were from the Lake Victoria agro-ecological zone, 30% were from Western, 15% from Eastern Kenya and 10% from the Coastal agro-ecological zone. This study adds data on potential mycotoxin hotspots in Kenya useful in employing targeted and regional mycotoxin mitigation strategies in efforts to avert future mycotoxicoses outbreaks in Kenya.

Universal screening of 200 mycotoxins and their variations in stored cereals in Shanghai, China by UHPLC-Q-TOF MS

Due to the challenge of hundreds of potential mycotoxins that may be present in cereals, a rapid and reliable ultra-high performance liquid chromatography coupled with quadrupole-time-of-flight tandem mass spectrometry (UHPLC-Q-TOF MS) technique was developed for universal screening of 200 mycotoxins (prototype, emerging and related derivatives) in cereals. With satisfactory sensitivity of accurate mass full-spectrum acquisition, it is feasible to preliminarily identify tentative untargeted mycotoxins with a large range of polarity without reference materials. The current screening method was also validated by the determination of 33 typical mycotoxins, and the screening detection limits in the range of 0.5–100 μg kg−1 were established in cereals. In total, 138 stored samples were contaminated by 46 mycotoxins and their metabolites, some of which were firstly reported in cereals, posing emerging potential health risks to humans and animals. Furthermore, the accumulation, transformation and degradation mechanisms of typical mycotoxins in cereals were investigated under real storage conditions.

The Fungal Microbiome of Wheat Flour Includes Potential Mycotoxin Producers.

Consumers are increasingly demanding higher quality and safety standards for the products they consume, and one of this is wheat flour, the basis of a wide variety of processed products. This major component in the diet of many communities can be contaminated by microorganisms before the grain harvest, or during the grain storage right before processing. These microorganisms include several fungal species, many of which produce mycotoxins, secondary metabolites that can cause severe acute and chronic disorders. Yet, we still know little about the overall composition of fungal communities associated with wheat flour. In this study, we contribute to fill this gap by characterizing the fungal microbiome of different types of wheat flour using culture-dependent and -independent techniques. Qualitatively, these approaches suggested similar results, highlighting the presence of several fungal taxa able to produce mycotoxins. In-vitro isolation of fungal species suggest a higher frequency of Penicillium, while metabarcoding suggest a higher abundance of Alternaria. This discrepancy might reside on the targeted portion of the community (alive vs. overall) or in the specific features of each technique. Thus, this study shows that commercial wheat flour hosts a wide fungal diversity with several taxa potentially representing concerns for consumers, aspects that need more attention throughout the food production chain.

Development of a Novel UPLC-MS/MS Method for the Simultaneous Determination of 16 Mycotoxins in Different Tea Categories.

The contamination of potential mycotoxins in tea production and consumption has always been a concern. However, the risk monitoring on multiple mycotoxins remains a challenge by existing methods due to the high cost and complex operation in tea matrices. This research has developed a simple ultra-performance liquid chromatography-tandem mass spectrometry strategy based on our homemade purification column, which can be applied in the detections of mycotoxins in complex tea matrices with high-effectively purifying and removing pigment capacity for 16 mycotoxins. The limits of detection and the limits of quantification were in the ranges of 0.015~15.00 and 0.03~30.00 µg·kg−1 for 16 mycotoxins, respectively. Recoveries from mycotoxin-fortified tea samples (0.13~1200 µg·kg−1) in different tea matrices ranged from 61.27 to 118.46%, with their relative standard deviations below 20%. Moreover, this method has been successfully applied to the analysis and investigation of the levels of 16 mycotoxins in major categories of tea and the monitoring of multiple mycotoxins in processed samples of ripened Pu-erh. In conclusion, the proposed strategy is simple, effective, time-saving, and low-cost for the determination of a large number of tea samples.

Temporal and spatial variation of microbial communities in stored rice grains from two major depots in China

Microbial activity in stored rice grains could cause quality deterioration and mycotoxin accumulation that may lead to serious economic losses and food safety risks. However, limited studies have examined the spatial and temporal variation of microbial communities associated with stored rice grains. Here, we performed amplicon sequence analysis to investigate the temporal and spatial distribution of microbes in stored rice grains from Chongqing grain depot (Southern China) and Liaoning grain depot (Northern China). Bacterial and fungal diversities, in addition to community structures of rice grains in Chongqing were significantly different from those in Liaoning in terms of α diversity (Chongqing > Liaoning, p <001) and β diversity (p < 0.001, bacterial communities: R = 0.9293, fungal communities: R = 1.0). The core bacterial taxa among stored rice grains comprised Pantoea, Pseudomonas, Rhizobium, and Methylobacterium, while the core fungal taxa comprised Alternaria, Aspergillus, and Cladosporium. In addition, different microbial communities were observed at different stored time points (i.e., post-harvest period, storage for one year, and storage for two years), and along different stored vertical depths (upper, middle, and lower layers) within the Chinese horizontal warehouse. The relative abundances of Aspergillus increased over storage time, but decreased with the increase of stored vertical depth within the warehouse. Temperature was the most important factor associated with differences in microbial communities across storage periods. The potential mycotoxin producing fungal species A. flavus and A. niger exhibited significantly higher abundances in rice grains of Chongqing compared to those of Liaoning. These data could be useful for evaluating potential risks of toxigenic fungi and mycotoxin contamination of stored rice grains. Further, these insights can help grain depot managers optimize storage conditions and reduce risks of deleterious fungi during rice grains storage.

Microbial Ecology of French Dry Fermented Sausages and Mycotoxin Risk Evaluation During Storage.

Dry fermented sausages are produced worldwide by well-controlled fermentation processes involving complex microbiota including many bacterial and fungal species with key technological roles. However, to date, fungal diversity on sausage casings during storage has not been fully described. In this context, we studied the microbial communities from dry fermented sausages naturally colonized or voluntarily surface inoculated with molds during storage using both culture-dependent and metabarcoding methods. Staphylococci and lactic acid bacteria largely dominated in samples, although some halotolerant genera (e.g., Halomonas, Tetragenococcus, and Celerinatantimonas spp.) were also frequently observed. Fungal populations varied from 7.2 to 9.8 log TFU/cm2 sausage casing during storage, suggesting relatively low count variability among products. Fungal diversity identified on voluntarily inoculated casings was lower (dominated by Penicillium nalgiovense and Debaryomyces hansenii) than naturally environment-inoculated fermented sausages (colonized by P. nalgiovense, Penicillium nordicum, and other Penicillium spp. and sporadically by Scopulariopsis sp., D. hansenii, and Candida zeylanoïdes). P. nalgiovense and D. hansenii were systematically identified, highlighting their key technological role. The mycotoxin risk was then evaluated, and in situ mycotoxin production of selected mold isolates was determined during pilot-scale sausage productions. Among the identified fungal species, P. nalgiovense was confirmed not to produce mycotoxins. However, some P. nordicum, Penicillium chrysogenum, Penicillium bialowienzense, Penicillium brevicompactum, and Penicillium citreonigrum isolates produced one or more mycotoxins in vitro. P. nordicum also produced ochratoxin A during pilot-scale sausage productions using “worst-case” conditions in the absence of biotic competition. These data provide new knowledge on fermented sausage microbiota and the potential mycotoxin risk during storage.

Infection Process and Genome Assembly Provide Insights into the Pathogenic Mechanism of Destructive Mycoparasite Calcarisporium cordycipiticola with Host Specificity.

Calcarisporium cordycipiticola is the pathogen in the white mildew disease of Cordyceps militaris, one of the popular mushrooms. This disease frequently occurs and there is no effective method for disease prevention and control. In the present study, C. militaris is found to be the only host of C. cordycipiticola, indicating strict host specificity. The infection process was monitored by fluorescent labeling and scanning and transmission electron microscopes. C. cordycipiticola can invade into the gaps among hyphae of the fruiting bodies of the host and fill them gradually. It can degrade the hyphae of the host by both direct contact and noncontact. The parasitism is initially biotrophic, and then necrotrophic as mycoparasitic interaction progresses. The approximate chromosome-level genome assembly of C. cordycipiticola yielded an N50 length of 5.45 Mbp and a total size of 34.51 Mbp, encoding 10,443 proteins. Phylogenomic analysis revealed that C. cordycipiticola is phylogenetically close to its specific host, C. militaris. A comparative genomic analysis showed that the number of CAZymes of C. cordycipiticola was much less than in other mycoparasites, which might be attributed to its host specificity. Secondary metabolite cluster analysis disclosed the great biosynthetic capabilities and potential mycotoxin production capability. This study provides insights into the potential pathogenesis and interaction between mycoparasite and its host.

Contamination of Fusarium proliferatum and Aspergillus flavus in the Rice Chain Linked to Crop Seasons, Cultivation Regions, and Traditional Agricultural Practices in Mekong Delta, Vietnam.

This study evaluates the influence of crop seasons, cultivation regions, and traditional agricultural practices on the occurrence of F. proliferatum and A. flavus in the rice chain in the Mekong Delta, Vietnam. A survey on pre- and post-harvest practices was performed from 2017 to 2019 in parallel with sampling. Results showed that F. proliferatum (36.3%) and A. flavus (10%) were predominantly present throughout the rice chain. These fungi frequently occurred in winter–spring and autumn–winter crops in Can Tho paddy. Especially, F. proliferatum appeared both on the field and during transportation (50–100%), while A. flavus presented at all stages (10–33%). The occurrence of F. proliferatum reduced 70–27% after drying, depended on the seasons, compared to field and transportation stages and could not be detected anymore at further stages. Applying poor pre-harvest agricultural practices such as the use of certain varieties (Jasmine, DT8 varieties), combination of fertilizers (organic–inorganic), fields with crop debris, unhygienic boats, and delayed drying time of 8–12 h or 12–28 h resulted in an increase in fungal contamination on paddy. This study provides a detailed description of fungi contamination in crop seasons, cultivation regions, and agricultural practices, which may help in understanding the fungal dynamic and allow identification of good agricultural practices to mitigate the fungal contamination and potential mycotoxin production.

Mycotoxin Production in Fusarium According to Contemporary Species Concepts.

Fusarium is one of the most important genera of plant-pathogenic fungi in the world and arguably the world's most important mycotoxin-producing genus. Fusarium species produce a staggering array of toxic metabolites that contribute to plant disease and mycotoxicoses in humans and other animals. A thorough understanding of the mycotoxin potential of individual species is crucial for assessing the toxicological risks associated with Fusarium diseases. There are thousands of reports of mycotoxin production by various species, and there have been numerous attempts to summarize them. These efforts have been complicated by competing classification systems based on morphology, sexual compatibility, and phylogenetic relationships. The current depth of knowledge of Fusarium genomes and mycotoxin biosynthetic pathways provides insights into how mycotoxin production is distributedamong species and multispecies lineages (species complexes) in the genus as well as opportunities to clarify and predict mycotoxin risks connected with known and newly described species. Here, we summarize mycotoxin production in the genus Fusarium and how mycotoxin risk aligns with current phylogenetic species concepts.

Contamination of Wheat, Barley, and Maize Seeds with Toxigenic Fusarium Species and Their Mycotoxins in Tunisia.

Fusarium is a worldwide distributed fungal genus. It includes different species pathogenic to cereals among others crops. Some of these species can also produce toxic compounds toward animals and humans. In this work, occurrence of fumonisins B1+B2, zearalenone, type A trichothecenes (T-2 and HT-2 toxins), and type B trichothecenes (deoxynivalenol[DON] and nivalenol[NIV]) was studied in 65 samples of stored and freshly harvested wheat, barley, and maize collected in Tunisia. Mycotoxins analyses were performed by using gas chromatography for type B trichothecenes and HPLC for other mycotoxins. Obtained results were compared with the presence of mycotoxigenic species considered responsible for their synthesis by using species-specific polymerase chain reaction (PCR). Fumonisins occurred in 20.83% of wheat, 40% of barley, and 57.14% of maize samples, at levels exceeding European limits and suggesting a risk in Tunisian cereals, especially maize. Zearalenone, DON, NIV, and T-2+HT-2 toxins were detected at lower values in only wheat and barley samples. PCR protocols showed the predominance of F. verticillioides especially in maize, and occurrence of F. equiseti and F. graminearum in wheat and barley, and F. proliferatum in only two maize samples. A very consistent correlation was found between the detection of F. verticillioides and the contamination by fumonisins, as well as between the presence of F. graminearum and the contamination by zearalenone, DON, and NIV in the analyzed cereals. Consequently, the detection of Fusarium species with the current PCR assays strategy in wheat, barley, and maize grains may be considered predictive of their potential mycotoxin risk in these matrices. This work is the first to report information on the occurrence of fumonisins, trichothecene, and ZEN, together with their potentially producing Fusarium species in wheat, barley, and maize in Tunisia. The high level of fumonisins in cereals, especially maize, stresses the importance of the control and the regularization of these mycotoxins for food safety.

Mycotoxins in Ethiopia: A Review on Prevalence, Economic and Health Impacts.

Mycotoxigenic fungi and their toxins are a global concern, causing huge economic and health impacts in developing countries such as Ethiopia, where the mycotoxin control system is inadequate. This work aimed to review the occurrences of agriculturally essential fungi such as Aspergillus, Fusarium, and Penicillium and their major mycotoxins in Ethiopian food/feedstuffs. The incidents of crucial toxins, including aflatoxins (B1, B2, G1, G2, M1), fumonisins (B1, B2), zearalenone, deoxynivalenol, and ochratoxin A, were studied. The impacts of chronic aflatoxin exposure on liver cancer risks, synergy with chronic hepatitis B infection, and possible links with Ethiopian childhood malnutrition were thoroughly examined. In addition, health risks of other potential mycotoxin exposure are also discussed, and the impacts of unsafe level of mycotoxin contaminations on economically essential export products and livestock productions were assessed. Feasible mycotoxin mitigation strategies such as biocontrol methods and binding agents (bentonite) were recommended because they are relatively cheap for low-income farmers and widely available in Ethiopia, respectively. Moreover, Ethiopian mycotoxin regulations, storage practice, adulteration practice, mycotoxin tests, and knowledge gaps among value chain actors were highlighted. Finally, sustained public awareness was suggested, along with technical and human capacity developments in the food control sector.

Contamination of freshly harvested Bambara groundnut (Vigna subterranea) seed from Mpumalanga, South Africa, with mycotoxigenic fungi

AbstractFreshly harvested Bambara groundnut (BGN) is occasionally consumed raw and can potentially become infected with mycotoxingenic field fungi. In this study, BGN samples were obtained from 12 farms in three districts of Mpumalanga in South Africa. Eight pooled samples were screened for multi‐mycotoxin contamination using Ultra Performance Liquid‐Chromatography tandem mass spectrometry (UPLC‐MS/MS). To identify mycoflora, 12 samples were screened using conventional and molecular methods. Selected potential mycotoxin producing isolates were screened for mycotoxins using UPLC‐MS/MS. No mycotoxins were detected on the freshly harvested BGN samples, but they were infected with various mycotoxin producing fungal species namely Aspergillus flavus (50%), Penicillium citrinum (25%), Penicillium oxalicum (17%), Penicillium citreoviridin (0.8%), and Fusarium verticillioides (0.8%). Following screening of selected fungal cultures, aflatoxin B1 (0.4, 0.45 and 0.4 ppm) and fumonisin B1 (0.7 ppm) were detected from A. flavus and F. verticillioides, respectively. Identification of mycotoxigenic fungi on freshly harvested BGN presents a potential health risk.

Bioactive Metabolites and Potential Mycotoxins Produced by Cordyceps Fungi: A Review of Safety.

Ascomycete Cordyceps fungi such as C. militaris, C. cicadae, and C. guangdongensis have been mass produced on artificial media either as food supplements or health additives while the byproducts of culture substrates are largely used as animal feed. The safety concerns associated with the daily consumption of Cordyceps fungi or related products are still being debated. On the one hand, the known compounds from these fungi such as adenosine analogs cordycepin and pentostatin have demonstrated different beneficial or pharmaceutical activities but also dose-dependent cytotoxicities, neurological toxicities and or toxicological effects in humans and animals. On the other hand, the possibility of mycotoxin production by Cordyceps fungi has not been completely ruled out. In contrast to a few metabolites identified, an array of biosynthetic gene clusters (BGCs) are encoded in each genome of these fungi with the potential to produce a plethora of as yet unknown secondary metabolites. Conservation analysis of BGCs suggests that mycotoxin analogs of PR-toxin and trichothecenes might be produced by Cordyceps fungi. Future elucidation of the compounds produced by these functionally unknown BGCs, and in-depth assessments of metabolite bioactivity and chemical safety, will not only facilitate the safe use of Cordyceps fungi as human food or alternative medicine, but will also benefit the use of mass production byproducts as animal feed. To corroborate the long record of use as a traditional medicine, future efforts will also benefit the exploration of Cordyceps fungi for pharmaceutical purposes.

Fumonisin and Beauvericin Chemotypes and Genotypes of the Sister Species Fusarium subglutinans and Fusarium temperatum.

Fusarium subglutinans and Fusarium temperatum are common maize pathogens that produce mycotoxins and cause plant disease. The ability of these species to produce beauvericin and fumonisin mycotoxins is not settled, as reports of toxin production are not concordant. Our objective was to clarify this situation by determining both the chemotypes and genotypes for strains from both species. We analyzed 25 strains from Argentina, 13 F. subglutinans and 12 F. temperatum strains, for toxin production by ultraperformance liquid chromatography mass spectrometry (UPLC-MS). We used new genome sequences from two strains of F. subglutinans and one strain of F. temperatum, plus genomes of other Fusarium species, to determine the presence of functional gene clusters for the synthesis of these toxins. None of the strains examined from either species produced fumonisins. These strains also lack Fum biosynthetic genes but retain homologs of some genes that flank the Fum cluster in Fusarium verticillioides None of the F. subglutinans strains we examined produced beauvericin although 9 of 12 F. temperatum strains did. A complete beauvericin (Bea) gene cluster was present in all three new genome sequences. The Bea1 gene was presumably functional in F. temperatum but was not functional in F. subglutinans due to a large insertion and multiple mutations that resulted in premature stop codons. The accumulation of only a few mutations expected to disrupt Bea1 suggests that the process of its inactivation is relatively recent. Thus, none of the strains of F. subglutinans or F. temperatum we examined produce fumonisins, and the strains of F. subglutinans examined also cannot produce beauvericin. Variation in the ability of strains of F. temperatum to produce beauvericin requires further study and could reflect the recent shared ancestry of these two species.IMPORTANCEFusarium subglutinans and F. temperatum are sister species and maize pathogens commonly isolated worldwide that can produce several mycotoxins and cause seedling disease, stalk rot, and ear rot. The ability of these species to produce beauvericin and fumonisin mycotoxins is not settled, as reports of toxin production are not concordant at the species level. Our results are consistent with previous reports that strains of F. subglutinans produce neither fumonisins nor beauvericin. The status of toxin production by F. temperatum needs further work. Our strains of F. temperatum did not produce fumonisins, while some strains produced beauvericin and others did not. These results enable more accurate risk assessments of potential mycotoxin contamination if strains of these species are present. The nature of the genetic inactivation of BEA1 is consistent with its relatively recent occurrence and the close phylogenetic relationship of the two sister species.

Microbiological quality, fungal diversity and aflatoxins contamination in carob flour (Prosopis flexuosa)

Carob flour is obtained from pods of some species of Prosopis, leguminous trees that abound in many desert habitats worldwide. Currently, this product is available in healthy food stores in several countries, including Argentina, as a nontraditional meal of growing interest with multiple applications for the preparation of puddings, biscuits and snacks, among others. The objective of the present study was to evaluate the microbial quality of carob flour on basis of the presence of deteriorative and pathogenic microorganisms. Fungal diversity of the mycobiota was also studied with a special interest in toxigenic fungi. Eighteen samples of carob flour (Prosopis flexuosa) were analysed. Standard plate count of aerobic mesophilic bacteria showed levels of contamination ranging from <102 (estimative) to 6.8 × 105 CFU/g; total coliforms from <102 (estimative) to 4.7 × 105 CFU/g; moulds and yeasts from 2.1 × 102 to 8.1 × 104. In all samples, the absence of Salmonella sp. was verified in 25 g and counts of Bacillus cereus less than 102 were observed. These results indicate that from the safety point of view the carob flour studied does not have a significant microbial load. Regarding to fungal contamination, Aspergillus and Penicillium were the genera more diverse in species and were present in all the samples. Some of the species identified were potential mycotoxins producers. Among the most frequently detected species in the studied mycobiota were the Aspergillus of the Flavi section, well recognized as potential aflatoxin producers. The A. flavus species was one of the most widely distributed, since it was detected in almost all samples. A. parasiticus and A. arachidicola were found more sporadically. Aflatoxins analysis demonstrated that a high proportion of the samples were contaminated with aflatoxins in concentrations relatively low, ranging from 1.26 to 20.33 μg/kg of total aflatoxins. Type G aflatoxins are much less frequent contaminants than type B aflatoxins, which is consistent with the fact that A. parasiticus and A. arachidicola (producers of type B and G aflatoxins) were detected sporadically, while A. flavus, which produces aflatoxins B1 and B2, was present in a high number of samples. Results of the present work indicate that carob flour is susceptible to Aspergillus section Flavi and aflatoxin contamination and should be subjected to aflatoxin monitoring prior to marketing as required for other traditional crops.

High-throughput analysis of fungal communities in Myristicae Semen

Myristicae Semen (nutmeg) has been extensively used for a long time because of its pharmaceutical properties and edible values. However, nutmeg is susceptible to fungi and mycotoxin contamination under suitable conditions during growing or post-harvest, thereby posing considerable hazards to consumers and resulting in significant economic losses. In this study, the surface fungi of nutmegs collected from producing areas and commercial markets were investigated for the first time by targeting the internal transcribed spacer 2 region using an Illumina MiSeq PE250 platform. Fungal contaminations were detected in all 13 tested samples. Aspergillus was the most prevailing fungi at the genus level with the relative abundance of 4.37%–82.81%, followed by Xerochrysium (0.36%–55.18%), Xeromyces (0.87%–86.38%), Hyphopichia (0.06%–29.14%), and Alternaria (0.03%–52.28%). Meanwhile, 108 fungal taxa were identified at the species level with six potential mycotoxin-producing fungi, such as Aspergillus fumigatus, Penicillium steckii, and Penicillium capsulatum. The differences between two groups of fungal communities were monitored. In conclusion, amplicon sequencing features a wide application prospect for fungal community analysis in spices and herbs and provides an early warning for subsequent potential mycotoxin biosynthesis.