Natural Occurrence and Co-Contamination of Twelve Mycotoxins in Industry-Submitted Cool-Season Cereal Grains Grown under a Low Heat Unit Climate Condition

Interaction of beauvericin in combination with antibiotics against methicillin-resistant Staphylococcus aureus and Salmonella typhimurium

Multidrug resistance in bacteria is a major challenge worldwide, increasing both mortality by infections and costs for the health systems. Therefore, it is of utmost importance to find new drugs against resistant bacteria. Beauvericin (BEA) is a mycotoxin produced by entomopathogenic and other fungi of the genus Fusarium. Our work determines the effect of BEA combined with antibiotics, which has not been previously explored. The combination analysis included different antibiotics against non-methicillin-resistant Staphylococcus aureus (NT-MRSA), methicillin-resistant Staphylococcus aureus (MRSA), and Salmonella typhimurium. BEA showed a synergy effect with oxacillin with a fractional inhibitory concentration index (FICI) = 0.373 and an additive effect in combination with lincomycin (FICI = 0.507) against MRSA. In contrast, it was an antagonist when combined with ciprofloxacin against S. typhimurium. We propose BEA as a molecule with the potential for the development of new therapies in combination with current antibiotics against multidrug-resistant bacteria.

Isolation, identification, degradation mechanism and exploration of active enzymes in the ochratoxin A degrading strain Acinetobacter pittii AP19

Ochratoxin A (OTA) is a polyketide mycotoxin that commonly contaminates agricultural products and causes significant economic losses. In this study, the efficient OTA-degrading strain AP19 was isolated from vineyard soil and was identified as Acinetobacter pittii. Compared with growth in nutrient broth supplemented with OTA (OTA-NB), strain AP19 grew faster in nutrient broth (NB), but the ability of the resulting cell lysates to remove OTA was weaker. After cultivation in NB, the cell lysate of strain AP19 was able to remove 100% of 1 mg/L OTA within 18 h. The cell lysate fraction > 30 kDa degraded 100% of OTA within 12 h, while the fractions < 30 kDa were practically unable to degrade OTA. Further anion exchange chromatography of the > 30 kDa fraction yielded two peaks exhibiting significant OTA degradation activity. The degradation product was identified as OTα. Amino acid metabolism exhibited major transcriptional trends in the response of AP19 to OTA. The dacC gene encoding carboxypeptidase was identified as one of the contributors to OTA degradation. Soil samples inoculated with strain AP19 showed significant OTA degradation. These results provide significant insights into the discovery of novel functions in A. pittii, as well as its potential as an OTA decomposer.

Essential oils: An eco-friendly alternative for controlling toxigenic fungi in cereal grains

Fungi are widely disseminated in the environment and are major food contaminants, colonizing plant tissues throughout the production chain, from preharvest to postharvest, causing diseases. As a result, grain development and seed germination are affected, reducing grain quality and nutritional value. Some fungal species can also produce mycotoxins, toxic secondary metabolites for vertebrate animals. Natural compounds, such as essential oils, have been used to control fungal diseases in cereal grains due to their antimicrobial activity that may inhibit fungal growth. These compounds have been associated with reduced mycotoxin contamination, primarily related to reducing toxin production by toxigenic fungi. However, little is known about the mechanisms of action of these compounds against mycotoxigenic fungi. In this review, we address important information on the mechanisms of action of essential oils and their antifungal and antimycotoxigenic properties, recent technological strategies for food industry applications, and the potential toxicity of essential oils.

Mycotoxins in Cereal-Based Products and Their Impacts on the Health of Humans, Livestock Animals and Pets

Cereal grains are the most important food staples for human beings and livestock animals. They can be processed into various types of food and feed products such as bread, pasta, breakfast cereals, cake, snacks, beer, complete feed, and pet foods. However, cereal grains are vulnerable to the contamination of soil microorganisms, particularly molds. The toxigenic fungi/molds not only cause quality deterioration and grain loss, but also produce toxic secondary metabolites, mycotoxins, which can cause acute toxicity, death, and chronic diseases such as cancer, immunity suppression, growth impairment, and neural tube defects in humans, livestock animals and pets. To protect human beings and animals from these health risks, many countries have established/adopted regulations to limit exposure to mycotoxins. The purpose of this review is to update the evidence regarding the occurrence and co-occurrence of mycotoxins in cereal grains and cereal-derived food and feed products and their health impacts on human beings, livestock animals and pets. The effort for safe food and feed supplies including prevention technologies, detoxification technologies/methods and up-to-date regulation limits of frequently detected mycotoxins in cereal grains for food and feed in major cereal-producing countries are also provided. Some important areas worthy of further investigation are proposed.

Natural Occurrence of Regulated and Emerging Mycotoxins in Wheat Grains and Assessment of the Risks from Dietary Mycotoxins Exposure in China

Wheat grains are susceptible to contamination with various natural mycotoxins including regulated and emerging mycotoxins. This study surveyed the natural presence of regulated mycotoxins, such as deoxynivalenol (DON) and zearalenone (ZEN), and emerging mycotoxins such as beauvericin (BEA), enniatins (ENNs such as ENA, ENA1, ENB, ENB1) and Alternaria mycotoxins (i.e., alternariol monomethyl ether (AME), alternariol (AOH), tenuazonic acid (TeA), tentoxin (TEN), and altenuene (ALT)) in wheat grains randomly collected from eight provinces across China in 2021. The results revealed that each wheat grain sample was detected with at least one type of mycotoxin. The detection rates of these mycotoxins ranged from 7.1% to 100%, with the average occurrence level ranging from 1.11 to 921.8 µg/kg. DON and TeA were the predominant mycotoxins with respect to both prevalence and concentration. Approximately 99.7% of samples were found to contain more than one toxin, and the co-occurrence of ten toxins (DON + ZEN + ENA + ENA1 + ENB + ENB1 + AME + AOH + TeA + TEN) was the most frequently detected combination. The dietary exposure to different mycotoxins among Chinese consumers aged 4-70 years was as follows: 0.592-0.992 µg/kg b.w./day for DON, 0.007-0.012 µg/kg b.w./day for ZEN, 0.0003-0.007 µg/kg b.w./day for BEA and ENNs, 0.223-0.373 µg/kg b.w./day for TeA, and 0.025-0.041 µg/kg b.w./day for TEN, which were lower than the health-based guidance values for each mycotoxin, with the corresponding hazard quotient (HQ) being far lower than 1, implying a tolerable health risk for Chinese consumers. However, the estimated dietary exposure to AME and AOH was in the range of 0.003-0.007 µg/kg b.w./day, exceeding the Threshold of Toxicological Concern (TTC) value of 0.0025 µg/kg b.w./day, demonstrating potential dietary risks for Chinese consumers. Therefore, developing practical control and management strategies is essential for controlling mycotoxins contamination in the agricultural systems, thereby ensuring public health.

Occurrence of Fusarium mycotoxins in freshly harvested highland barley (qingke) grains from Tibet, China

Highland barley, also called "qingke" in Tibetan, is mainly cultivated in the Tibetan Plateau of China and has been used as a major staple food for Tibetans. Recently, Fusarium head blight (FHB) of qingke was frequently observed around the Brahmaputra River in Tibet. Considering the importance of qingke for Tibetans, the assessment of Fusarium mycotoxin contamination is essential for food safety. In this study, a total of 150 freshly harvested qingke grain samples were obtained from three regions around the Brahmaputra River in Tibet (China) in 2020. The samples were investigated for the occurrence of 20 Fusarium mycotoxins using high-performance liquid chromatography-tandem mass spectrometry (HPLC‒MS/MS). The most frequently occurring mycotoxin was enniatin B (ENB) (46%), followed by enniatin B₁ (ENB₁) (14.7%), zearalenone (ZEN) (6.0%), enniatin A₁ (ENA₁) (3.3%), enniatin A (ENA) (1.3%), beauvericin (BEA) (0.7%), and nivalenol (NIV) (0.7%). Due to the increase in altitude, the cumulative precipitation level and average temperature decreased from the downstream to the upstream of the Brahmaputra River; this directly correlated to the contamination level of ENB in qingke, which gradually decreased from downstream to upstream. In addition, the level of ENB in qingke obtained from qingke-rape rotation was significantly lower than that from qingke-wheat and qingke-qingke rotations (p < 0.05). These results disseminated the occurrence of Fusarium mycotoxins and provided further understanding of the effect of environmental factors and crop rotation on Fusarium mycotoxins.

Isolation, Identification and Characterization of Paenibacillus pabuli E1 to Explore Its Aflatoxin B1 Degradation Potential

Aflatoxin B₁ (AFB₁) contamination in feed and food seriously threatens the healthy growth of animals and humans, and it may lead to huge economic losses in livestock and poultry production. Therefore, screening of high-efficient AFB₁-degrading bacteria is necessary to ensure the safety of feed and food. The study aims to isolate and characterize bacteria from various sources to explore its AFB₁ degradation potential. Fifteen bacterial were obtained using a medium containing coumarin as the sole carbon source; only one strain showed a good-degrading ability in culture media by adding AFB₁ and it was selected for further studies. A gram-negative and spore-forming, designated E1, was identified as Paenibacillus pabuli, with the highest sequence similarity to P. pabuli NBRC13638^T (98.97%). The growth of the strain E1 was observed under 22-47 °C, pH 5.5-9.5 and NaCl concentration 0-6% (w/v), with optimum growth at 37 °C, pH 7.5 and 1% NaCl. The biodegradation characteristics of object strain were detected by high performance liquid chromatography (HPLC). The degradation ratio of AFB₁ reached 55% at 24 h and 70.2% at 48 h. After 96 h, the degradation rate of AFB₁ reached 85.9%. The active degradation components were present in the cell-free supernatant of strain E1, and the degradation ratio of AFB₁ reached 80.0% after 96 h. It is the first report that genus Paenibacillus could degrade AFB₁. Moreover, E1 has highly adaptable to diverse environmental conditions. It will be a potential candidate for biodegradation of mycotoxins in feed and food.

Comparative assessment of spray nozzles efficacy in the control of fusarium head blight in the barley crops using developed quantitative PCR assay

Fusarium species infect cereal spikes during anthesis and cause Fusarium head blight (FHB), a destructive disease of cereal crops with worldwide economic relevance. The necessity for these phytopathogenic fungi effective control becomes increasingly important for the production of both cultivated plants and those plants seeds. Fungicide application is a key methodology for controlling the disease development and mycotoxin contamination in cereals. Polymerase chain reaction (PCR) is currently the most commonly admitted DNA-based technology for specific, rapid and precise Fusarium detection. We have developed and patented the method for detection and quantitative determination of phytopathogenic fungi F. avenaceum and F. graminearum in plant seeds using Real-Time PCR with a pair of primers, designed to amplify sequences of the internal transcribed spacer at the ribosomal RNA gene cluster of those phytopathogenic fungi. This study was aimed to perform a comparative assessment of the efficacy of different spray nozzles for antifungal treatment to control F. avenaceum and F. graminearum infection of barley grains using a developed qPCR diagnostic system. A single application of a fungicide (active ingredient's content: 250 g/l propiconazole, 80 g/l cyproconazole) at BBCH 65 (middle of flowering) was carried out. For this purpose, four spray nozzles with different technical characteristics were used: Flat Fan 030, Amistar 030, Defy 3D 030 and Vegetable 060 (Pentair, USA). DNA-based fungi detection and identification was performed using conventional PCR and developed qPCR. The level of mycotoxins in barley grain was determined using enzyme-linked immunosorbent assay (ELISA). Grain count in the ear of barley and thousand seed weight (TSW) were also examined. A single application of the fungicide inhibited the development of FHB and is accompanied by the slight increase of TSW values in treated plants. It was found, that the most effective fungicide was against F. avenaceum and F. graminearum. The inhibitory effect depended on sprayer type. According to qPCR results, the best performance was achieved when using Amistar 030 and Flat Fan (FF) 030 sprayers. The average concentration of deoxynivalenol (DON) content in all barley grain samples were up to 4 times higher than the permissible level. Overall, because of the high contamination levels, found in tested samples, it is possible to state that a single application of the fungicide at the flowering phase was not able to effectively reduce DON contamination in barley samples. The developed test-system for qPCR provides new important information in the study of the effectiveness of fungicides and development of strategies to control FHB in cereals, not achievable with conventional PCR.

Aspergillus derived mycotoxins in food and the environment: Prevalence, detection, and toxicity

Aspergillus species are the paramount ubiquitous fungi that contaminate various food substrates and produce biochemicals known as mycotoxins. Aflatoxins (AFTs), ochratoxin A (OTA), patulin (PAT), citrinin (CIT), aflatrem (AT), secalonic acids (SA), cyclopiazonic acid (CPA), terrein (TR), sterigmatocystin (ST) and gliotoxin (GT), and other toxins produced by species of Aspergillus plays a major role in food and human health. Mycotoxins exhibited wide range of toxicity to the humans and animal models even at nanomolar (nM) concentration. Consumption of detrimental mycotoxins adulterated foodstuffs affects human and animal health even trace amounts. Bioaerosols consisting of spores and hyphal fragments are active elicitors of bronchial irritation and allergy, and challenging to the public health. Aspergillus is the furthermost predominant environmental contaminant unswervingly defile lives with a 40-90 % mortality risk in patients with conceded immunity. Genomics, proteomics, transcriptomics, and metabolomics approaches useful for mycotoxins' detection which are expensive. Antibody based detection of toxins chemotypes may result in cross-reactivity and uncertainty. Aptamers (APT) are single stranded DNA (ssDNA/RNA), are specifically binds to the target molecules can be generated by systematic evolution of ligands through exponential enrichment (SELEX). APT are fast, sensitive, simple, in-expensive, and field-deployable rapid point of care (POC) detection of toxins, and a better alternative to antibodies.

Integration of computational tools, data analysis and social science into food safety risk assessment

The EU-FORA Fellowship Programme 'Integration of tools and social science into food safety risk assessments' was proposed by the Food Standards Agency (FSA), the government department responsible for food safety in the UK. The working programme was organised into four modules, covering different areas of risk assessment, including microbiological risk assessment, chemical risk assessment, exposure assessment, risk prioritisation and the integration of risk assessment with social science. During this period, the fellow had the unique opportunity to gain experience in different fields of risk assessment, namely how to conduct a systematic review, to assess the risk of microbiological and chemical hazards, to make use of modelling tools for exposure assessment and risk prioritisation, to write scientific reports for committees and networks at the national level and to understand the role of social science in risk assessment. In addition, the fellow was able to attend several meetings, seminars, courses and workshops that helped him to gain further insight in the field of food science. The complete programme enabled a fast learning curve that allowed the fellow to have an overview of the different tools that can be employed in the wide field of food safety risk assessment, in order to acquire skills and competences that can be used in his future career.

A competitive immunoassay based on engineered magnetic/fluorescent nanoparticles and biolayer interferometry-based assay for T-2 toxin determination

For the first time a competitive immunoassay was developed by employing T-2 antibody-functionalized magnetite nanoparticles and T-2 toxin-conjugated fluorescent quantum dots (QDs). Free T-2 and the T-2-modified QDs compete for binding to antibody-modified magnetic beads; the magnetic beads collected by magnetic separation were subjected to fluorescence intensity analysis (with excitation/emission wavelengths at 460/616 nm). This competitive immunoassay for T-2 toxin determination was applied both in a microcentrifuge tube and on a 96-well plate. The dynamic range of the immunoassay is 1-100 ng mL^-1, the limit of detection (LOD) is 0.1 ng mL^-1, and determination was completed in about 40 min and 30 min in the microcentrifuge tube and 96-well plate, respectively. Moreover, the biolayer interferometry (BLI) technique was employed for T-2 determination for the first time, in which the conjugate of T-2 toxin and bovine serum albumin (BSA) was immobilized on the sensors before detection. Its average recovery of T-2 toxin from barley sample ranged from 82.00 to 123.33%, and the relative standard deviation (RSD) was between 9.42 and 15.73%. The LOD of the BLI-based assay is 5 ng mL^-1, and it only takes 10 min to finish the determination. Graphical abstract.

Incidence and exposure assessment of aflatoxins and ochratoxin A in Egyptian wheat

Aflatoxins and ochratoxin A occur frequently in grains and are associated with carcinogenic, and nephrotoxic properties. Therefore, the aim of this study was to determine the level of aflatoxins and ochratoxin A contamination in wheat samples obtained from different Egyptian governorates and to assess the effect of gamma irradiation on AFB₁ in spiked wheat samples, as well as to evaluate the estimated daily intake and hazard index. Thirty-six wheat grain samples purchased from different sale points were analyzed by High-Performance Liquid Chromatography. Data revealed that 33.33 % of the wheat grain samples were contaminated by aflatoxin B₁, whereas only 16.66 % of the wheat samples were above the maximum limits (2 μg/kg) set by the European Commission. Ochratoxin A was only detected in two wheat grain samples, and the results were considered below the maximum limit (5 μg/kg) set by the European Commission. On studying the effect of gamma irradiation on wheat samples spiked by aflatoxin B₁ (20 μg/kg), results revealed that aflatoxin B₁ was reduced to 1.22 and 0.94 μg/kg for samples gamma-irradiated at a dose of 10 and 20 KGy respectively. Estimated daily intake of ochratoxin A in wheat samples was found to be higher than that of the tolerable daily intake; however, hazard index values were below one, thus demonstrating no threat to human health.

Prevalence and Exposure Assessment of Aflatoxins Through Black Tea Consumption in the Multan City of Pakistan and the Impact of Tea Making Process on Aflatoxins

Aflatoxins are the highly toxic secondary metabolites of certain fungi, being mainly produced by Aspergillus flavus and Aspergillus parasiticus. Aflatoxins are classified as group 1 category carcinogens by the International Agency for Research on Cancer (IARC). A large number of food commodities are reported to be contaminated with aflatoxins. Tea is the world's second most consumed beverage and the consumption of tea is increasing day by day. Besides being a source of several health promoting substances, tea leaves are also reported to be contaminated with aflatoxins. However, not a single study is reported from Pakistan regarding the level of aflatoxins in commercially available black tea samples. The current study aimed to quantify the level of aflatoxins in commercially available branded and non-branded black tea samples. The estimated daily intake (EDI) of aflatoxins through branded and non-branded black tea consumption and the health risk assessment based on margin of exposure (MOE) approach was assessed. Furthermore, the impact of local tea making processes on the concentration of aflatoxins in tea beverage (filtrate) was also investigated.

Occurrence and Co-Occurrence of Mycotoxins in Cereal-Based Feed and Food

Dietary (co)-exposure to mycotoxins is associated with human and animal health concerns as well as economic losses. This study aims to give a data-based insight from the scientific literature on the (co-)occurrence of mycotoxins (i.e., parent and modified forms) in European core cereals, and to estimate potential patterns of co-exposure in humans and animals. Mycotoxins were mainly reported in wheat and maize showing the highest concentrations of fumonisins (FBs), deoxynivalenol (DON), aflatoxins (AFs), and zearalenone (ZEN). The maximum concentrations of FB1+FB2 were reported in maize both in feed and food and were above legal maximum levels (MLs). Similar results were observed in DON-food, whose max concentrations in wheat, barley, maize, and oat exceeded the MLs. Co-occurrence was reported in 54.9% of total records, meaning that they were co-contaminated with at least two mycotoxins. In the context of parental mycotoxins, co-occurrence of DON was frequently observed with FBs in maize and ZEN in wheat; DON + NIV and DON + T2/HT2 were frequently reported in barley and oat, respectively. Apart from the occurrence of ZEN and its phase I and phase II modified forms, only a limited number of quantified data were available for other modified forms; i.e., mainly the acetyl derivatives of DON. Data gaps are highlighted together with the need for monitoring studies on multiple mycotoxins to identify co-occurrence patterns for parent mycotoxins, metabolites, and their modified forms.

Multiple Mycotoxins Determination in Food by LC-MS/MS: An International Collaborative Study

An intercollaborative study was organized to evaluate the performance characteristics of a liquid chromatography tandem mass spectrometry procedure for the simultaneous determination of 12 mycotoxins in food, which were ochratoxin A, aflatoxins B1, B2, G1, G2, and M1, deoxynivalenol, zearalenone, fumonisins B1 and B2, and T-2 and HT-2 toxins. The method combined the simplicity of the QuEChERS (Quick, Easy, Cheap, Efficient, Rugged and Safe) approach with the efficiency of immunoaffinity column cleanup (the step used to enhance sensitivity and sample cleanup for some matrices only). Twenty-three entities were enrolled and were European reference laboratories for mycotoxin analysis, U.S. and European service laboratories, and Nestlé laboratories. Each participant analyzed 28 incurred and/or spiked blind samples composed of spices, nuts, milk powder, dried fruits, cereals, and baby food using the protocol given. Method performances were assessed according to ISO 5725-2. Relative standard deviations of repeatability and reproducibility and trueness values for each of the 115 mycotoxin/sample combinations ranged from 5% to 23%, 7% to 26%, and 85% to 129%, respectively, in line with requirements defined in EC 401/2006. The overall set of data gathered demonstrated that the method offered a unique platform to ensure compliance with EC 1881/2006 and EC 165/2013 regulations setting maximum limits for mycotoxins in food samples, even at low regulated levels for foods intended for infants and young children. The method was applicable regardless of the food, the regulated mycotoxin, and the concentration level, and thus is an excellent candidate for future standardization.