Ochratoxin A: An overview on toxicity and carcinogenicity in animals and humans

Investigation of ochratoxin A in air-dry-cured hams

The European Union legislation regarding ochratoxin A (OTA) in various foodstuffs has changed relatively recently. Nevertheless, the legislation does not regulate OTA in any meat and meat-derived products. In this legislation update, the European Commission requested new studies, including, besides others, the presence of OTA in hams, which raises the concern that its consumption may pose a potential risk of exposure to OTA. This study aims to investigate OTA in a total of 195 samples of air-dry-cured hams acquired at the Czech market from January to June 2023. The analytical technique of high-performance liquid chromatography in combination with a fluorescence detector with pre-treatment employing immunoaffinity columns was used to determine OTA. OTA was found in 93 (48%) samples of air-dry-cured ham, with the OTA concentration reaching up to 14.58 ng/g. Due to the current absence of regulation limits, the results of this study were compared with the Italian maximum limit of 1 ng/g regulating OTA in porcine meat and byproducts. The Italian OTA maximum limit was exceeded in 22 (11%) samples. This study shows that the population of the Czech Republic is exposed to OTA from this pork byproduct. It is essential to set an OTA regulatory limit for meat and food produced from it to protect human health.

Rational design of molecularly imprinted electrochemical sensor based on Nb2C-MWCNTs heterostructures for highly sensitive and selective detection of Ochratoxin a

Developing an efficient method for screening Ochratoxin A (OTA) in agriculture products is vital to ensure food safety and human health. However, the complex food matrix seriously affects the sensitivity and accuracy. To address this issue, we designed a novel molecularly imprinted polymer (MIP) electrochemical sensor based on multiwalled carbon nanotube-modified niobium carbide (Nb2C-MWCNTs) with the aid of the density functional theory (DFT). In this design, a glassy carbon electrode (GCE) was first modified by Nb2C-MWCNTs heterostructure. Afterward, the MIP layer was prepared, with ortho-toluidine as a functional monomer selected via DFT and OTA acting as a template on the surface of Nb2C-MWCNTs/GCE using in-situ electropolymerization. Electrochemical tests and physical characterization revealed that Nb2C-MWCNTs improved the sensor's active surface area and electron transmission capacity. Nb2C-MWCNTs had a good synergistic effect on MIP, endowing the sensor with high sensitivity and specific recognition of OTA in complex food matrix systems. The MIP sensor showed a wide linear range from 0.04 to 10.0 μM with a limit of detection (LOD) of 3.6 nM. Moreover, it presented good repeatability and stability for its highly antifouling effect on OTA. In real sample analysis, the recoveries, ranging from 89.77% to 103.70%, agreed well with the results obtained by HPLC methods, suggesting the sensor has good accuracy and high potential in practical applications.

Shark anti-idiotypic variable new antigen receptor specific for an alpaca nanobody: Exploration of a nontoxic substitute to ochratoxin A in immunoassay

Nontoxic substitutes to mycotoxins can facilitate the development of eco-friendly immunoassays. To explore a novel nontoxic substitute to ochratoxin A (OTA), this study screened shark anti-idiotypic variable new antigen receptors (VNARs) against the alpaca anti-OTA nanobody Nb28 through phage display. After four rounds of biopanning of a naïve VNAR phage display library derived from six adult Chiloscyllium plagiosum sharks, one positive clone, namely, P-3, was validated through a phage enzyme-linked immunosorbent assay (phage ELISA). The recombinant anti-idiotypic VNAR AId-V3 was obtained by prokaryotic expression, and the interactions between Nb28 and AId-V3 were investigated via computer-assisted simulation. The affinity of AId-V3 for Nb28 and its heptamer Nb28-C4bpα was measured using Biacore assay. Combining Nb28-C4bpα with AId-V3, a novel direct competitive ELISA (dcELISA) was developed for OTA analysis, with a limit of detection of 0.44 ng/mL and a linear range of 1.77-32.25 ng/mL. The good selectivity, reliability, and precision of dcELISA were confirmed via cross-reaction analysis and recovery experiments. Seven commercial pepper powder samples were tested using dcELISA and validated using high-performance liquid chromatography. Overall, the shark anti-idiotypic VNAR was demonstrated as a promising nontoxic substitute to OTA, and the proposed method was confirmed as a reliable tool for detecting OTA in food.

Occurrence, evaluation, and human health risk assessment of ochratoxin a in infant formula and cereal-based baby food: a global literature systematic review

This study reviews global levels of ochratoxin A (OTA) in infant formula and cereal-based foods, using Monte Carlo simulation to assess risks. The review found 24 studies on global OTA levels in infant food and cereal-based products, using databases including PubMed, Scopus, Web of Science and Embase until March 2024. We estimated OTA exposure in infant food based on concentration, intake and body weight. The exposure and hazard quotient margin were calculated using BMDL10 and TDI values. Monte Carlo simulation evaluated human health risks from OTA in infant formula and cereal-based foods. A global study from 14 countries shows varying levels, surpassing EU limits in Tunisia, Ecuador, the USA, and generally in Africa, notably in infant cereals, which had higher levels than formula. Globally, OTA was present in 29.3% of the 3348 samples analyzed, with Lebanon at 95.2% and Brazil at 0%. Analysis indicates only non-carcinogenic risk for infants. While health risks for infants are mostly low, ongoing research and monitoring are vital to minimize OTA exposure in infant food.

Role of albumin in the metabolism and excretion of ochratoxin A

Ochratoxin A (OTA) is known to be strongly bound to serum albumin, but it remains unknown how albumin affects its metabolism and kinetics. To close this gap, we used a mouse model, where heterozygous albumin deletion reduces serum albumin to concentrations similar to hypoalbuminemic patients and completely eliminates albumin by a homozygous knockout. OTA and its potential metabolites (OTα, 4-OH-OTA, 7'-OH-OTA, OTHQ, OP-OTA, OTB-GSH, OTB-NAC, OTB) were time-dependently analyzed in plasma, bile, and urine by LC-MS/MS and were compared to previously published hepatotoxicity and nephrotoxicity data. Homozygous albumin deletion strongly accelerated plasma clearance as well as biliary and urinary excretion of the parent compound and its hydroxylation products. Decreasing albumin in mice by the heterozygous and even more by the homozygous knockout leads to an increase in the parent compound in urine which corresponded to increased nephrotoxicity. The role of albumin in OTA-induced hepatotoxicity is more complex, since heterozygous but not homozygous nor wild-type mice showed a strong biliary increase in the toxic open lactone OP-OTA. Correspondingly, OTA-induced hepatotoxicity was higher in heterozygous than in wild-type and homozygous animals. We present evidence that albumin-mediated retention of OTA in hepatocytes is required for formation of the toxic OP-OTA, while complete albumin elimination leads to rapid biliary clearance of OTA from hepatocytes with less formation of OP-OTA. In conclusion, albumin has a strong influence on metabolism and toxicity of OTA. In hypoalbuminemia, the parent OTA is associated with increased nephrotoxicity and the open lactone with increased hepatotoxicity.

Membrane Receptor-Mediated Disruption of Cellular Homeostasis: Changes in Intracellular Signaling Pathways Increase the Toxicity of Ochratoxin A

Organisms maintain their cellular homeostatic balance by interacting with their environment through the use of their cell surface receptors. Membrane based receptors such as the transforming growth factor β receptor (TGFR), the prolactin receptor (PRLR), and hepatocyte growth factor receptor (HGFR), along with their associated signaling cascade, play significant roles in retaining cellular homeostasis. While these receptors and related signaling pathways are essential for health of cell and organism, their dysregulation can lead to imbalance in cell function with severe pathological conditions such as cell death or cancer. Ochratoxin A (OTA) can disrupt cellular homeostasis by altering expression levels of these receptors and/or receptor-associated intracellular downstream signaling modulators and/or pattern and levels of their phosphorylation/dephosphorylation. Recent studies have shown that the activity of the TGFR, the PRLR, and HGFR and their associated signaling cascades change upon OTA exposure. A critical evaluation of these findings suggests that while increased activity of the HGFR and TGFR signaling pathways leads to an increase in cell survival and fibrosis, decreased activity of the PRLR signaling pathway leads to tissue damage. This review explores the roles of these receptors in OTA-related pathologies and effects on cellular homeostasis.

Biodegradation of ochratoxin A by Brevundimonas diminuta HAU429: Characterized performance, toxicity evaluation and functional enzymes

Ochratoxin A (OTA) is a notorious mycotoxin commonly contaminating food products worldwide. In this study, an OTA-degrading strain Brevundimonas diminuta HAU429 was isolated by using hippuryl-L-phenylalanine as the sole carbon source. The biodegradation of OTA by strain HAU429 was a synergistic effect of intracellular and extracellular enzymes, which transformed OTA into ochratoxin α (OTα) through peptide bond cleavage. Cytotoxicity tests and cell metabolomics confirmed that the transformation of OTA into OTα resulted in the detoxification of its hepatotoxicity since OTA but not OTα disturbed redox homeostasis and induced oxidative damage to hepatocytes. Genome mining identified nine OTA hydrolase candidates in strain HAU429. They were heterologously expressed in Escherichia coli, and three novel amidohydrolase BT6, BT7 and BT9 were found to display OTA-hydrolyzing activity. BT6, BT7 and BT9 showed less than 45 % sequence identity with previously identified OTA-degrading amidohydrolases. BT6 and BT7 shared 60.9 % amino acid sequence identity, and exhibited much higher activity towards OTA than BT9. BT6 and BT7 could completely degrade 1 μg mL-1 of OTA within 1 h and 50 min, while BT9 hydrolyzed 100 % of OTA in the reaction mixture by 12 h. BT6 was the most thermostable retaining 38 % of activity after incubation at 70 °C for 10 min, while BT7 displayed the highest tolerance to ethanal remaining 76 % of activity in the presence of 6 % ethanol. This study could provide new insights towards microbial OTA degradation and promote the development of enzyme-catalyzed OTA detoxification during food processing.

A comprehensive review of mycotoxins: Toxicology, detection, and effective mitigation approaches

Mycotoxins, harmful compounds produced by fungal pathogens, pose a severe threat to food safety and consumer health. Some commonly produced mycotoxins such as aflatoxins, ochratoxin A, fumonisins, trichothecenes, zearalenone, and patulin have serious health implications in humans and animals. Mycotoxin contamination is particularly concerning in regions heavily reliant on staple foods like grains, cereals, and nuts. Preventing mycotoxin contamination is crucial for a sustainable food supply. Chromatographic methods like thin layer chromatography (TLC), gas chromatography (GC), high-performance liquid chromatography (HPLC), and liquid chromatography coupled with a mass spectrometer (LC/MS), are commonly used to detect mycotoxins; however, there is a need for on-site, rapid, and cost-effective detection methods. Currently, enzyme-linked immunosorbent assays (ELISA), lateral flow assays (LFAs), and biosensors are becoming popular analytical tools for rapid detection. Meanwhile, preventing mycotoxin contamination is crucial for food safety and a sustainable food supply. Physical, chemical, and biological approaches have been used to inhibit fungal growth and mycotoxin production. However, new strains resistant to conventional methods have led to the exploration of novel strategies like cold atmospheric plasma (CAP) technology, polyphenols and flavonoids, magnetic materials and nanoparticles, and natural essential oils (NEOs). This paper reviews recent scientific research on mycotoxin toxicity, explores advancements in detecting mycotoxins in various foods, and evaluates the effectiveness of innovative mitigation strategies for controlling and detoxifying mycotoxins.

Mg2+-promoted high-efficiency DNA conjugation on polydopamine surfaces for aptamer-based ochratoxin A detection

BACKGROUND

Surface immobilization of DNA is the foundation of a broad range of applications in biosensing and specific DNA extraction. Polydopamine (PDA) coatings can serve as intermediate layers to immobilize amino- or thiol-labelled molecules, including DNA, onto various materials through Michael addition and/or Schiff base reactions. However, the conjugation efficiency is limited by electrostatic repulsion between negatively charged DNA and PDA. Recently, it has been reported that polyvalent metal ions (such as Mg2+ and Ca2+) can mediate the adsorption of DNA on PDA surfaces. Inspired by this, in this work we aimed to exploit polyvalent metal ions to facilitate the conjugation of DNA on PDA.

RESULTS

Mg2+ was used to promote the conjugation of amino-terminated DNA complementary to ochratoxin A (OTA) aptamer (cDNA-NH2) on PDA-coated magnetic nanoparticles (Fe3O4@PDA). After the reaction, the unlinked cDNA-NH2 adsorbed on Fe3O4@PDA mediated by Mg2+ was removed with EDTA. In the presence of 20 mM Mg2+, the amount of covalently linked cDNA-NH2 increased approximately 11-fold compared to that in the absence of Mg2+. The resulting Fe3O4@PDA@cDNA conjugates exhibited superior hybridization capacity towards OTA aptamers, minimal nonspecific adsorption, and excellent chemical stability. The conjugates combined with fluorophore-labelled aptamers were employed for OTA detection, achieving a limit of detection (LOD) of 2.77 ng mL-1. To demonstrate versatility, this conjugation method was extended to Ca2+-promoted conjugation of cDNA-NH2 on Fe3O4@PDA nanoparticles and Mg2+-promoted conjugation of cDNA-NH2 on PDA-coated 96-well plates.

SIGNIFICANCE

The conjugation efficiency of DNA on PDA was significantly improved with the assistance of polyvalent metal ions (Mg2+ and Ca2+), providing a facile and efficient method for DNA immobilization. Due to the substrate-independent adhesion property of PDA, this method demonstrates versatility in DNA surface modification and holds great potential for applications in target extraction, biosensing, and other fields.

Ochratoxin A (OTA) causes intestinal aging damage through the NLRP3 signaling pathway mediated by calcium overload and oxidative stress

Ochratoxin A (OTA) is a widespread environmental toxin that poses a serious threat to human and animal health. OTA has been shown to cause cellular and tissue damage and is a global public health problem. However, the effects of OTA on gastrointestinal aging have not been reported. The aim of this study was to investigate the effects of OTA on intestinal aging in vitro and in vivo. In vitro experiments showed that OTA induced cellular inflammation through calcium overload and oxidative stress, significantly up-regulated the expression of P16, P21, and P53 proteins, markedly increased senescence-associated β-galactosidase activity (SA-β-gal) positive cells, and obviously decreased the expression of proliferating cell nuclear antigen (PCNA) proteins, which led to intestinal cell senescence. Meanwhile, we found that treatment with β-carotene ameliorated OTA-induced intestinal cell senescence. Consistent with the results of the in vitro experiments, in vivo studies showed that the intestinal aging of mice fed OTA was significantly higher than that of the control group. In conclusion, OTA may induce intestinal aging through calcium overload, oxidative stress and inflammation. This study lays a foundation for further research on the toxicological effects of OTA.

Disruption of intestinal epithelial permeability in the Co-culture system of Caco-2/HT29-MTX cells exposed individually or simultaneously to acrylamide and ochratoxin A

Mycotoxins and thermal processing hazards are common contaminants in various foods and cause severe problems in terms of food safety and health. Combined use of acrylamide (AA) and ochratoxin A (OTA) would result in more significant intestinal toxicity than either toxin alone, but the underlying mechanisms behind this poor outcome remain unclear. Herein, we established the co-culture system of Caco-2/HT29-MTX cells for simulating a real intestinal environment that is more sensitive to AA and OTA, and showed that the combination of AA and OTA could up-regulate permeability of the intestine via increasing LY permeabilization, and decreasing TEER, then induce oxidative stress imbalance (GSH, SOD, MDA, and ROS) and inflammatory system disorder (TNF-α, IL-1β, IL-10, and IL-6), thereby leading a rapid decline in cell viability. Western blot, PAS- and AB-staining revealed that AA and OTA showed a synergistic effect on the intestine mainly through the disruption of tight junctions (TJs) and a mucus layer. Furthermore, based on correlation analysis, oxidative stress was more relevant to the mucus layer and TJs. Therefore, our findings provide a better evaluation model and a potential mechanism for further determining or preventing the combined toxicity caused by AA and OTA.

Involvement of pro-inflammatory mediators and cell cycle disruption in neuronal cells induced by gliotoxin and ochratoxin A after individual and combined exposure

Mycotoxins such as gliotoxin (GTX) and ochratoxin A (OTA) are secondary metabolites of Aspergillus and Penicillum found in food and feed. Both mycotoxins have shown to exert a detrimental effect on neuronal activity. The following study was carried out to elucidate the mechanisms by which GTX and OTA exert their toxicity. Non-differentiated SH-SY5Y neuronal-like cells were treated with GTX, OTA and their combinations to assess their cytotoxic effect using the MTT assay during 24, 48 and 72 h of exposure. Based on the results of the cytotoxic assays, cell cycle proliferation and immunological mediators were measured by determining the production of IL-6 and TNF-α using flow cytometry and ELISA, respectively. The IC50 values obtained were 1.24 and 1.35 µM when SH-SY5Y cells were treated with GTX at 48 h and 72 h, respectively. IC50 values of 8.25, 5.49 and 4.5 µM were obtained for OTA treatment at 24 h, 48 h and 72 h, respectively. The SubG0 phase increased in both treatments at 24 and 48 h. On the other hand, IL-6 and TNF-α production was increased in all mycotoxin treatments studied and was more pronounced for [GTX + OTA] after 48 h exposure. The additive and synergistic effect observed by the isobologram analysis between GTX and OTA resulted to a higher cytotoxicity which can be explained by the increased production of IL-6 and TNF-α inflammatory mediators that play an important role in the toxicity mechanism of these mycotoxins.

Mg2+- or Ca2+-regulated aptamer adsorption on polydopamine-coated magnetic nanoparticles for fluorescence detection of ochratoxin A

It has been observed that polyvalent metal ions can mediate the adsorption of DNA on polydopamine (PDA) surfaces. Exploiting this, we used two divalent metal ions (Mg2+ or Ca2+) to promote the adsorption of fluorescence-labelled ochratoxin A (OTA) aptamers on PDA-coated magnetic nanoparticles (Fe3O4@PDA). Based on the different adsorption affinities of free aptamers and OTA-bound aptamers, a facile assay method was established for OTA detection. The aptamers adsorbed on Fe3O4@PDA were removed via simple magnetic separation, and the remaining aptamers in the supernatant exhibited a positive correlation with the OTA concentration. The concentrations of Mg2+ and Ca2+ were finely tuned to attain the optimal adsorption affinity and sensitivity for OTA detection. In addition, other factors, including the Fe3O4@PDA dosage, pH, mixing order, and incubation time, were studied. Finally, under optimized conditions, a detection limit (3σ/s) of 1.26 ng/mL was achieved for OTA. Real samples of spiked red wine were analysed with this aptamer-based method. This is the first report of regulating aptamer adsorption on the PDA surface with polyvalent metal ions for OTA detection. By changing the aptamers, the method can be easily extended to other target analytes.

A new and promiscuous α/β hydrolase from Acinetobacter tandoii DSM 14970 T inactivates the mycotoxin ochratoxin A

The presence of ochratoxin A (OTA) in food and feed represents a serious concern since it raises severe health implications. Bacterial strains of the Acinetobacter genus hydrolyse the amide bond of OTA yielding non-toxic OTα and L-β-phenylalanine; in particular, the carboxypeptidase PJ15_1540 from Acinetobacter sp. neg1 has been identified as an OTA-degrading enzyme. Here, we describe the ability to transform OTA of cell-free protein extracts from Acinetobacter tandoii DSM 14970 T, a strain isolated from sludge plants, and also report on the finding of a new and promiscuous α/β hydrolase (ABH), with close homologs highly distributed within the Acinetobacter genus. ABH from A. tandoii (AtABH) exhibited amidase activity against OTA and OTB mycotoxins, as well as against several carboxypeptidase substrates. The predicted structure of AtABH reveals an α/β hydrolase core composed of a parallel, six-stranded β-sheet, with a large cap domain similar to the marine esterase EprEst. Further biochemical analyses of AtABH reveal that it is an efficient esterase with a similar specificity profile as EprEst. Molecular docking studies rendered a consistent OTA-binding mode. We proposed a potential procedure for preparing new OTA-degrading enzymes starting from promiscuous α/β hydrolases based on our results. KEY POINTS: • AtABH is a promiscuous αβ hydrolase with both esterase and amidohydrolase activities • AtABH hydrolyses the amide bond of ochratoxin A rendering nontoxic OTα • Promiscuous αβ hydrolases are a possible source of new OTA-degrading enzymes.

Natural feed additives and bioactive supplements versus chemical additives as a safe and practical approach to combat foodborne mycotoxicoses

This review highlights the possible hazard of mycotoxins occurrence in foods and feeds in regards to foodborne diseases. The possible management of the risk of contamination of foods and feeds with mycotoxins by using natural feed additives, protecting against deleterious effects of mycotoxins or inhibiting the growth of fungi and mycotoxin production, is deeply investigated in the available literature and some effective measures for safe utilization of mycotoxin contaminated feed/food are proposed. The biological methods of decontamination, degradation or biotransformation of mycotoxins are deeply analyzed and discussed. Some natural antagonists against target fungi are also reviewed and a comparison is made with conventional fungicides for ensuring a safe prevention of mycotoxin contamination. The most common and useful chemical methods of mycotoxins decontamination of agricultural commodities or raw materials are also investigated, e.g., chemical additives inactivating or destroying and/or adsorbing mycotoxins as well as chemical additives inhibiting the growth of fungi and mycotoxin production. The practical use and safety of various kind of feed/food additives or herbal/biological supplements as possible approach for ameliorating the adverse effects of some dangerous mycotoxins is deeply investigated and some suggestions are given. Various possibilities for decreasing mycotoxins toxicity, e.g., by clarifying the mechanisms of their toxicity and using some target antidotes and vitamins as supplements to the diet, are also studied in the literature and appropriate discussions or suggestions are made in this regard. Some studies on animal diets such as low carbohydrate intake, increased protein content, calorie restriction or the importance of dietary fats are also investigated in the available literature for possible amelioration of the ailments associated with mycotoxins exposure. It could be concluded that natural feed additives and bioactive supplements would be more safe and practical approach to combat foodborne mycotoxicoses as compared to chemical additives.

HLA gene variations and mycotoxin toxicity: Four case reports

Mycotoxins are produced by certain molds that can cause many health effects. We present four human cases of prolonged consistent mycotoxins exposure linked to genetic variations in human leukocyte antigen (HLA) alleles. The HLA-DR/DQ isotype alleles are linked to mycotoxins susceptibility due to the lack of proper immune response; individuals with these alleles are poor eliminators of mycotoxins from their system. Four subjects with variations in their HLA-DR alleles were exposed to mycotoxins from living in mold-infested houses and experienced persistent mold-related symptoms long after moving out from the mold-infested houses and only exposed to the levels of molds found in the ambient air. From one of the subjects, two urine samples were collected ~ 18 months apart after the cessation of exposure. Urinary elimination rate was extremely slow for two of the mycotoxins (ochratoxin A [OTA] and mycophenolic acid [MPA]) detected in both samples. In 18 months, decline in OTA level was only ~ 3-fold (estimated t½ of ~ 311 days) and decline in MPA level was ~ 11-fold (estimated t½ of ~ 160 days), which was ~ 10- and ~ 213-fold slower than expected in individuals without HLA-DR alleles, respectively. We estimated that ~ 4.3 and ~ 2.2 years will be required for OTA and MPA to reach < LLQ in urine, respectively. Three other subjects with variations in HLA-DR alleles were members of a family who lived in a mold-infested house for 4 years. They kept experiencing mold-related issues >2 years after moving to a non-mold-infested house. Consistent exposure was confirmed by the presence of several mycotoxins in urine >2 years after the secession of higher than background (from outdoor ambient air) exposure. This was consistent with the extremely slow elimination of mycotoxins from their system. Variations in HLA-DR alleles can, consequently, make even short periods of exposure to chronic exposure scenarios with related adverse health effects. It is, therefore, important to determine genetic predisposition as a reason for prolonged/lingering mold-related symptoms long after the cessation of higher than background exposure. Increased human exposure to mycotoxins is expected from increased mold infestation that is anticipated due to rising CO2, temperature, and humidity from the climate change with possibly increased adverse health effects, especially in individuals with genetic susceptibility to mold toxicity.

Practical Strategies to Reduce Ochratoxin A in Foods

Ochratoxin A (OTA), a potent nephrotoxin, is one of the most deleterious mycotoxins, with its prevalence in agricultural crops and their processed foods around the world. OTA is a major concern to food safety, as OTA exposure through dietary intake may lead to a significant level of accumulation in the body as a result of its long half-life (about 35 days). Its potent renal toxicity and high risk of exposure as well as the difficulty in controlling environmental factors OTA production has prompted the need for timely information on practical strategies for the food industry to effectively manage OTA contamination during food processing. The effects of various food processes, including both nonthermal and thermal methods, on the reduction in OTA were summarized in this review, with emphasis on the toxicity of residual OTA as well as its known and unknown degradation products. Since complete removal of OTA from foodstuffs is not feasible, additional strategies that may facilitate the reduction in OTA in food, such as adding baking soda and sugars, was also discussed, so that the industry may understand and apply practical measures to ensure the safety of its products destined for human consumption.

Ochratoxin A-enhanced glycolysis induces inflammatory responses in human gastric epithelium cells through mTOR/HIF-1α signaling pathway

Ochratoxin A (OTA) is a mycotoxin commonly found in several food commodities worldwide with potential nephrotoxic, hepatotoxic and carcinogenic effects. We previously showed for the first time that OTA treatment enhanced glycolysis in human gastric epithelium (GES-1) cells in vitro. Here, we found that OTA exposure activated inflammatory responses, evidenced by increasing of NF-κB signaling pathway-related protein (p-p65 and p-IκBα) expressions and elevating of inflammatory cytokine (IL-1β and IL-6) mRNA expressions in GES-1 cells. To elucidate the role of glycolysis in inflammatory effects triggered by OTA, we pretreated GES-1 cells with glycolysis inhibitor (2-deoxy-D-glucose, 2-DG) before OTA exposure. The result showed that 2-DG reduced the protein expressions of p-p65 and p-IκBα and alleviated the mRNA expressions of inflammatory cytokines in OTA-treated GES-1 cells. Furthermore, OTA activated the mTOR/HIF-1α pathway by increasing the protein expressions of p-mTOR, p-eIF4E and HIF-1α, and inhibition of mTOR with rapamycin or silencing HIF-1α with siRNA significantly attenuated OTA-enhanced glycolysis by reducing glycolysis related genes and thereby decreasing inflammatory effects of GES-1 cells. These results demonstrate that OTA activates inflammatory responses in GES-1 cells and this is controlled by mTOR/HIF-1α pathway-mediated glycolysis enhancement. Our findings provide a novel mechanistic view into OTA-induced gastric cytotoxicity.

Innovative approaches for mycotoxin detection in various food categories

Mycotoxins (MTs), produced by filamentous fungi, represent a severe hazard to the health of humans and food safety, affecting the quality of various agricultural products. They can contaminate a wide range of foods, during any processing phase before or after harvest. Animals and humans who consume MTs-contaminated food or feed may experience acute or chronic poisoning, which may result in serious pathological consequences. Accordingly, developing rapid, easy, and accurate methods of MTs detection in food becomes highly urgent and critical as a quality control and to guarantee food safety and lower health hazards. In this review, we highlighted and discussed innovative approaches like biosensors, fluorescent polarization, capillary electrophoresis, infrared spectroscopy, and electronic noses for MT identification pointing out current challenges and future directions. The limitations, current challenges, and future directions of conventional detection methods versus innovative methods have also been highlighted and discussed.

The Role of Probiotics in Improving Food Safety: Inactivation of Pathogens and Biological Toxins

Currently, many advances have been made in avoiding food contamination by numerous pathogenic and toxigenic microorganisms. Many studies have shown that different probiotics, in addition to having beneficial effects on the host's health, have a very good ability to eliminate and neutralize pathogens and their toxins in foods which leads to enhanced food safety. The present review purposes to comprehensively discuss the role of probiotics in improving food safety by inactivating pathogens (bacterial, fungal, viral, and parasite agents) and neutralizing their toxins in food products. Some recent examples in terms of the anti-microbial activities of probiotics in the body after consuming contaminated food have also been mentioned. This review shows that different probiotics have the potential to inactivate pathogens and neutralize and detoxify various biological agents in foods, as well as in the host body after consumption.

Gold nanoparticles as colorimetric probes in food analysis: Progress and challenges

The rapid, sensitive and reliable food safety control is urgently needed due to the harmful effects of the food contaminants on human health. Colorimetric approach has exhibited promising potential for the detection of food contaminants due to their easy preparation, rapid detection, high sensitivity, and naked-eye sensing. In recent years, AuNPs-based colorimetric probes have been extensively explored for food analysis. The present article reviews the development of AuNPs-based colorimetric probes for colorimetric sensing and their applications in food analysis. It generally summarizes the properties of AuNPs and introduces the preparation and functionalization methods of AuNPs. An overview of the colorimetric sensing mechanisms of AuNPs-based probes and their applications in analysis of food contaminants are also provided. Although AuNPs-based colorimetric probes show many advantages in detection of food contaminants, challenges remain in terms of complexity of food matrices, multiple analytes detection in a single go, and testing conditions interference.

Polysaccharide from walnut green husk alleviates liver inflammation and gluconeogenesis dysfunction by altering gut microbiota in ochratoxin A-induced mice

Walnut green husk polysaccharides (WGP) are isolated from the walnut green husk with a mean molecular weight of 12.77 kDa. The structural characterization revealed by methylation and NMR analysis indicated that WGP might consist of →4-α-D-Galp-(1→, α-D-Galp (1→, and →2)-α-L-Rhap-(1→. Previous studies have been demonstrated that WGP effectively prevented liver injury and modulated gut microbiota in high fructose-treated mice and high fat diet-treated rats. In this study, we found for the first time that WGP presenting outstanding protective effects on liver inflammation and gluconeogenesis dysfunction induced by ochratoxin A (OTA) in mice. Firstly, WGP decreased oxidative stress, down-regulated the expression of inflammatory factors and inhibited the TLR4/p65/IκBα pathway in the liver. Then, WGP reversed OTA-induced lower phosphoenolpyruvate carboxyl kinase (PEPCK), and glucose 6-phosphatase (G6PC) activities in the liver. Furthermore, WGP increased the diversity of gut microbiota and the abundance of beneficial bacteria, especially Lactobacillus and Akkermansia. Importantly, the results of fecal microbiota transplantation (FMT) experiment further confirmed that gut microbiota involved in the protective effects of WGP on liver damage induced by OTA. Our results indicated that the protective effect of WGP on liver inflammation and gluconeogenesis dysfunction caused by OTA may be due to the regulation of gut microbiota.

The nephrotoxin ochratoxin a impairs resilience of energy homeostasis of human proximal tubule cells

Despite a long history of research, the mode of action of the mycotoxin ochratoxin A (OTA) is still not clear. Based on our observation that OTA-exposed cells consume more glucose and produce more lactate than control cells, with this study, we want to suggest another possible mode of action of OTA, involving cellular metabolism and mitochondria. We exposed human proximal tubule cells (HK2 cells) to OTA and studied its influence on mitochondrial performance as well as on the expression of energy homeostasis-involved routing proteins (AMPK and TXNIP) and on glucose transporting and metabolizing proteins. OTA reduced the capacity of mitochondria to increase their oxygen consumption rate forcing the cells to switch to the ineffective anaerobic glycolysis which demands higher glucose availability. The higher glucose demand is met by augmented cellular glycogen degradation and increased glucose uptake capabilities by increasing glucose transporter expression. We conclude that OTA exposure leads to impaired mitochondria, which forces the cells to alter their metabolism in order to ensure energy supply. We suggest to consider a possible effect of OTA on metabolism and mitochondria and to have a closer look on OTA-induced changes in the metabolome as possible additional players in OTA toxicity.

Aspergillus ochraceus biocontrol by Hanseniaspora opuntiae in vitro and on coffee fruits

Aspergillus ochraceus is an ochratoxin-producing fungus which contaminates coffee. In this study the antifungal effect of the yeast Hanseniaspora opuntiae on three Aspergillus ochraceus strains (IOC 4417, IOC 4462, Ao 14) was evaluated in vitro and on coffee fruits. H. opuntiae (106 and 107 cells mL-1) reduced in vitro fungal growth from 82% to 87%, when co-cultivated with A. ochraceus. The yeast cell free supernatant (CFS) inhibited conidial germination from 76.5% to 92.5%, and hyphal growth from 54% to 78%. The yeast (107 and 109 cells mL-1) applied on coffee fruits delayed fruit decay by A. ochraceus (IOC 4417 and Ao 14) until the 9th day, and was significantly different (p < 0.05) from the controls. Furthermore, the ultrastructure of the yeast-fungus interaction on the coffee fruit surface showed yeast attachment to A. ochraceus hyphae, and morphological alterations in fungal structures, with hyphal abnormalities, such as tortuous hyphae with irregular, non-uniform surface compared to the control without yeast. H. opuntiae showed efficacy as biocontrol agent and, to the best of our knowledge, this is the first study on the antifungal activity of H. opuntiae against A. ochraceus on coffee fruits Nevertheless, application of H. opuntiae to the crop in the field requires further studies.

Co-occurrence of Mycotoxin-Induced Hepatotoxicity in Mice Inhibited by Lycopene: Mitochondrial Impairment and Early Hepatic Fibrosis

SCOPE

Mycotoxins co-contamination of agricultural products poses a serious threat to human and animal health, especially hepatic dysfunction. Zearalenone (ZEN), deoxynivalenol (DON), and aflatoxin B1 (AFB1) are three commonly co-occurring mycotoxins. This study is to determine whether lycopene (LYC) can alleviate hepatic toxicity induced by the co-occurrence of ZEN, DON, and AFB1 in mice.

METHODS AND RESULTS

Eighty 6-week-old male ICR mice are divided into four groups: CON group (solvent control), LYC group (10 mg kg-1 LYC), Co-M group (10 mg kg-1 ZEN + 1 mg kg-1 DON + 0.5 mg kg-1 AFB1), and LYC+Co-M group (10 mg kg-1 LYC + 10 mg kg-1 ZEN + 1 mg kg-1 DON + 0.5 mg kg-1 AFB1). The results show that LYC can suppress the co-occurrence of mycotoxin-induced mitochondrial swelling and vacuolization accompanied by dysregulation of indices of mitochondrial dynamics (Mitofusin 1 (Mfn1), Mfn2, Optic atrophy 1 (Opa1), Dynamin-related protein 1 (Drp1), Fission 1 (Fis1) at the mRNA level; DRP1 and FIS1 at the protein level). LYC effectively inhibits co-occurrence of mycotoxin-induced activation of Cytochrome P450 2E1, and early fibrosis, as determined by staining with Masson's trichrome and α-SMA protein.

CONCLUSION

LYC successfully attenuates early hepatic fibrosis mainly through antioxidant activities and prevented mitochondrial injury.

Ochratoxin A-The Current Knowledge Concerning Hepatotoxicity, Mode of Action and Possible Prevention

Ochratoxin A (OTA) is considered as the most toxic of the other ochratoxins synthesized by various fungal species belonging to the Aspergillus and Penicillium families. OTA commonly contaminates food and beverages, resulting in animal and human health issues. The toxicity of OTA is known to cause liver damage and is still being researched. However, current findings do not provide clear insights into the toxin mechanism of action. The current studies focusing on the use of potentially protective compounds against the effects of the toxin are insufficient as they are mainly conducted on animals. Further research is required to fill the existing gaps in both fields (namely the exact OTA molecular mechanism and the prevention of its toxicity in the human liver). This review article is a summary of the so far obtained results of studies focusing on the OTA hepatotoxicity, its mode of action, and the known approaches of liver cells protection, which may be the base for expanding other research in near future.

The Effect of Mycotoxins and Their Mixtures on Bovine Spermatozoa Characteristics

There is growing concern about the effects of mycotoxins on mammalian reproduction. Although the effects of single mycotoxins have been well documented, the impact of their mixtures on spermatozoon quality is less known. Here, frozen-thawed semen (n = 6 bulls) was in-vitro-cultured (2 h) without (control) or with (i) a single mycotoxin [zearalenone (ZEN), ochratoxin A (OTA), toxin 2 (T2), and diacetoxyscirpenol (DAS)] in a dose-response manner; (ii) binary mixtures (OTA + T2, OTA + ZEN, OTA + DAS, ZEN + T2, DAS + T2 and ZEN + DAS); or (iii) ternary mixtures (OTA + DAS + T2, OTA + ZEN + T2, and ZEN + DAS + T2). Then, the spermatozoa quality was characterized according to its plasma- and acrosome-membrane integrity, mitochondrial membrane potential, and oxidation status by a flow cytometer. Exposure to single mycotoxins or binary mixtures did not affect the spermatozoa characteristics. However, exposure to the ternary mixtures, OTA + DAS + T2 and OTA + ZEN + T2, reduced (p < 0.05) the mitochondrial membrane potential relative to the control. In addition, OTA + ZEN + T2 increased (p < 0.05) the proportion of spermatozoa with reactive oxygen species relative to the control. The most suggested interaction effect between the mycotoxins was found to be an additive one. A synergistic interaction, mainly regarding the oxidation status of the spermatozoa, was also found between the mycotoxins. The current study sheds light on the potential risk of exposing spermatozoa to a mycotoxin mixture.

Yeasts as sustainable biocontrol agents against ochratoxigenic Aspergillus species and in vitro optimization of ochratoxin A detoxification

AIMS

The aims of this study were to evaluate the potential of Hanseniaspora opuntiae, Meyerozyma caribbica, and Kluyveromyces marxianus for in vitro biocontrol of Aspergillus ochraceus, A. westerdijkiae, and A. carbonarius growth, the ochratoxin A (OTA) effect on yeast growth, and yeast in vitro OTA detoxification ability using an experimental design to predict the combined effects of inoculum size, incubation time, and OTA concentration.

METHODS AND RESULTS

Predictive models were developed using an incomplete Box-Behnken experimental design to predict the combined effects of inoculum size, incubation time, and OTA concentration on OTA detoxification by the yeasts. The yeasts were able to inhibit fungal growth from 13% to 86%. Kluyveromyces marxianus was the most efficient in inhibiting the three Aspergillus species. Furthermore, high OTA levels (100 ng ml-1) did not affect yeast growth over 72 h incubation. The models showed that the maximum OTA detoxification under optimum conditions was 86.8% (H. opuntiae), 79.3% (M. caribbica), and 73.7% (K. marxianus), with no significant difference (P > 0.05) between the values predicted and the results obtained experimentally.

CONCLUSION

The yeasts showed potential for biocontrol of ochratoxigenic fungi and OTA detoxification, and the models developed are important tools for predicting the best conditions for the application of these yeasts as detoxification agents.

Recent Progress in Screening of Mycotoxins in Foods and Other Commodities Using MXenes-Based Nanomaterials

Mycotoxin pollution in agricultural food products endangers animal and human health during the supply chains, therefore the development of accurate and rapid techniques for the determination of mycotoxins is of great importance for food safety guarantee. MXenes-based nanoprobes have attracted enormous attention as a complementary analysis and promising alternative strategies to conventional diagnostic methods, because of their fascinating features, like high electrical conductivity, various surface functional groups, high surface area, superb thermal resistance, good hydrophilicity, and environmentally-friendlier characteristics. In this study, we outline the state-of-the-art research on MXenes-based probes in detecting various mycotoxins like aflatoxin, ochratoxin, deoxynivalenol, zearalenone, and other toxins as a most commonly founded mycotoxin in the agri-food supply chain. First, we present the diverse synthesis approaches and exceptional characteristics of MXenes. Afterward, based on the detecting mechanism, we divide the biosensing utilizations of MXenes into two subcategories: electrochemical, and optical biosensors. Then their performance in effective sensing of mycotoxins is comprehensively deliberated. Finally, present challenges and prospective opportunities for MXenes are debated.

Survey of knowledge, and attitudes to storage practices preempting the occurrence of filamentous fungi and mycotoxins in some Ghanaian staple foods and processed products

Mycotoxigenic fungi can infect and produce potent mycotoxins in foodstuffs prior to harvest, during harvest (field fungi), and in storage after harvest (storage fungi), which when ingested, can result in adverse health effects. This study was aimed at assessing the knowledge, attitudes, and practices adopted by the Ghanaian populace to help mitigate the occurrence of molds and mycotoxins in foods. A cross-sectional survey involving a structured questionnaire was conducted with 642 respondents from twelve regions of Ghana. Descriptive statistics and analyses of variance were calculated. Correct Classification Rate (CCR) was measured to assess the utility of a logistic regression model. The results of the study showed that the majority of 299 (46.6%) of the respondents were between the ages of 18-25. Age and educational level were related to knowledge about the occurrence of fungi and mycotoxins in foods (p < 0.05). More than half the respondents, 50% indicated that they knew of aflatoxins as a major mycotoxin present in food. Higher education directly influenced on the knowledge of mycotoxicosis and the management of stored food to present intoxication by fungal metabolites. 502 (32.9%) knew that consuming foods with toxins could cause stomach aches. The most commonly consumed food commodity despite the presence of visible growth of fungi was bread (35.3%). The average KAP score for knowledge showed that, out of 100%, there was adequate knowledge (63.8%) among the members of the Ghanaian populace. Favorable environmental conditions of high humidity (> 85% ERH) and temperature (> 28-32 °C) enhance the proliferation of fungi in most foods and the attendant production of mycotoxins such as aflatoxins, ochratoxins, and fumonisins are associated with several severe human and animal health conditions; mycotoxicosis was associated with high fever, pain, vomiting, suppression of immunity, cancer, etc. when these foods are consumed on regular basis for a prolonged length of time. Future examination of the food items used for the School Feeding Programme in Ghana will offer opportunities to examine the risks of feeding youth with fungal-contaminated food preparations from providers.

Passion fruit-inspired dendritic mesoporous silica nanospheres-enriched quantum dots coupled with magnetism-controllable aptasensor enable sensitive detection of ochratoxin A in food products

Ochratoxin A (OTA) is a powerful mycotoxin present in a variety of food products, and its detection is important for human health. Here, a fluorescent aptasensor is reported for sensitive OTA determination. Specifically, the surface of bio-inspired passion fruit-like dendritic mesoporous silica nanospheres-enriched quantum dots (MSNQs-apt) was first modified with the OTA aptamer as the recognition unit and fluorescence emitter, while the aptamer-complementary DNA (MNPs-cDNA) was linked with the magnetic nanoparticles (MNPs) as the separation element. In the range of 2.56 pg/mL to 8 ng/mL, the proposed aptasensor exhibited satisfactory linearity and a detection limit of 1.402 pg/mL. The developed aptasensor achieved recoveries of 90.98-103.20% and 94.33-107.57 % in red wine and wheat flour samples, respectively. By simply replacing the aptamer, this aptasensor can be easily extended to detection of other analytes, suggesting its potential as a universal detection platform for mycotoxins in food products.

Fluorescent Sensor Based on Magnetic Separation and Strand Displacement Amplification for the Sensitive Detection of Ochratoxin A

Ochratoxin A (OTA) is a common mycotoxin, and it is a significant threat to human health throughout the food chain. In this study, a sensitive and specific fluorescent sensor based on magnetic separation technology combined with chain displacement amplification was developed for fast and easy detection of OTA in food. The designed strand displacement amplification can improve the sensitivity for the detection, and the magnetic nanomaterials can provide a large surface area, thus enhancing the capture efficiency of the target from the sample. Based on those designs, the experimental results showed that the proposed method displayed excellent performance. The linearity range was 0.5-128.0 ng/mL. The detection limit was 0.125 ng/mL; the relative standard deviations were 3.92-7.71%. Additionally, the developed method was satisfactorily applied to determine OTA in wheat, corn, and red wine samples at three spiked levels (1.0, 8.0, and 64.0 ng/mL). The recoveries ranged from 85.45 to 107.8% for wheat flour, 101.34 to 108.35% for corn flour, and 91.15 to 93.80% for red wine, respectively. Compared with high-performance liquid chromatography, the proposed method showed a lower limit of detection and equal recovery. Hence, the designed method is a potential and good detecting tool for OTA residue analysis in complex matrix samples.

Revisiting the Role of NAG across the Continuum of Kidney Disease

Acute and chronic kidney diseases are an evolving continuum for which reliable biomarkers of early disease are lacking. The potential use of glycosidases, enzymes involved in carbohydrate metabolism, in kidney disease detection has been under investigation since the 1960s. N-acetyl-beta-D-glucosaminidase (NAG) is a glycosidase commonly found in proximal tubule epithelial cells (PTECs). Due to its large molecular weight, plasma-soluble NAG cannot pass the glomerular filtration barrier; thus, increased urinary concentration of NAG (uNAG) may suggest injury to the proximal tubule. As the PTECs are the workhorses of the kidney that perform much of the filtration and reabsorption, they are a common starting point in acute and chronic kidney disease. NAG has previously been researched, and it is widely used as a valuable biomarker in both acute and chronic kidney disease, as well as in patients suffering from diabetes mellitus, heart failure, and other chronic diseases leading to kidney failure. Here, we present an overview of the research pertaining to uNAG’s biomarker potential across the spectrum of kidney disease, with an additional emphasis on environmental nephrotoxic substance exposure. In spite of a large body of evidence strongly suggesting connections between uNAG levels and multiple kidney pathologies, focused clinical validation tests and knowledge on underlining molecular mechanisms are largely lacking.

Ultra-sensitive determination of Ochratoxin A in coffee and tea samples using a novel semi-automated in-syringe based coagulant-assisted fast mycotoxin extraction (FaMEx) technique coupled with UHPLC-MS/MS

In this study, we demonstrated a novel semi-automated in-syringe-based coagulant-assisted liquid-liquid microextraction (IS-CGA-LLME) as fast mycotoxin extraction (FaMEx) technique coupled with ultra-high-performance liquid chromatography connected with a tandem-mass spectrometer (UHPLC-MS/MS) for the quantification of mycotoxin (Ochratoxin A, OT-A) in coffee and tea samples. IS-CGA-LLME is a three-step extraction process that includes extraction of OT-A from sample matrix using low-volume solvent extraction, then the extractant was cleaned-up using a coagulation process, and finally, the decolorized/matrix removed sample solution was processed for LLME for target analyte's pre-concentration. The final extractant was analyzed using UHPLC-MS/MS for OT-A quantification. Under the optimized experimental conditions, highly sensitive detection and quantification limits were obtained at 0.001 and 0.003 ng g^-1 for OT-A with excellent extraction recovery (93-111%) and precision <10%. These results proved that the developed method is a simple, highly sensitive, semi-automated, low-matrix effect and efficient procedure for the determination of mycotoxins in food samples.

Toxicogenic fungal profile, Ochratoxin A exposure and cancer risk characterization through maize (Zea mays) consumed by different age populations in the Volta region of Ghana

Maize (Zea mays) is an important staple food crop for the majority of Ghanaians. Maize is mostly contaminated by fungal species and particularly mycotoxins. This work aimed to identify and quantify the incidence of fungal infection and exposure to Ochratoxin A (OTA) as well as the health risk characterization in different age populations due to maize consumption in the Volta region. Maize samples were plated on Dichloran Rose Bengal Chloramphenicol (DRBC) agar, and Oxytetracycline Glucose Yeast Extract (OGYE) agar. All media were prepared in accordance with the manufacturers' instructions. The plates were incubated at 28 ± 2 °C for 5-7 days. High-Performance Liquid Chromatography connected to a fluorescence detector (HPLC-FLD) was used to analyze the ochratoxin A (OTA) levels in maize. Cancer risk assessments were also conducted using models prescribed by the Joint FAO/WHO Expert Committee on Additives (JECFA). The maize samples collected from the Volta region contained fungal population between the range of 3.08-4.58 log10 CFU/g. Eight (8) genera were recorded belonging to Aspergillus, Trichoderma, Penicillium, Fusarium, Saccharomyces, Mucor, Rhodotorula and Rhizopus. The species diversity includes A. flavus, A. niger, T. harzianum, P. verrucosum, F. oxysporum, Yeast, F. verticillioides, Rhodotorulla sp, A. fumigatus, R. stolonifer, M. racemosus species. Additionally, the ochratoxins level contained in the samples were very noteworthy and ranged from 1.22 to 28.17 μg/kg. Cancer risk assessments of OTA produced outcomes also ranged between 2.15 and 524.54 ng/kg bw/day, 0.03-8.31, 0.0323, and 0.07-16.94 for cases/100,000 person/yr for Estimated Daily Intake (EDI), Margin of Exposure (MOE), Average Potency, and Cancer Risks respectively for all age categories investigated. There was very high mycoflora load on the maize sampled from the Volta region, likewise the range of mycotoxins present in the maize grains, suggesting the potential to pose some adverse health effects with the populace of the Volta region.

Ascorbic Acid-Mediated in situ Growth of Gold Nanostars for Photothermal Immunoassay of Ochratoxin A

Currently, the development of efficient mycotoxins detection methods, particularly using portable devices as readout devices, remains a great challenge. Herein, a photothermal enzyme-linked immunosorbent assay (ELISA) based on gold nanostars (AuNSs) for the detection of ochratoxin A (OTA) using a "thermometer" was proposed for the first time. AuNSs with photothermal conversion capacity were parepared using an ascorbic acid (AA)-mediated in situ growth methd. Quantification was based on the alkaline phosphatase catalyzing the dephosphorylation of ascorbic acid 2-phosphoate to AA, thereby converting OTA concentration to the amount of in situ synthesized AuNSs, thus achieving straightforward readout by temperature. Benefiting from the classical tyramine signal amplification strategy, a detection limit of 0.39 ng mL^-1 was obtained. The recoveries of grape juice and maize samples spiked with 10 ng mL^-1 and 30 ng mL^-1 OTA ranged from 86.53% to 116.9%. Our method has great potential in on-site OTA detection for food safety.

Protective Effect of alpha-Tocopherol against Ochratoxin A in Kidney Cell Line HK-2

Food safety is a top priority for the protection of infants and young children. Ochratoxin A (OTA) is an emerging concern due to its high toxicity and occurrence in a wide range of agricultural crops and their derived food products including those foods and snacks destined for infants and young children. OTA is considered as a possible human carcinogen and its main target organ is the kidney. The objective of this study was to investigate the protective effect of α-tocopherol against oxidative stress induced by OTA using human proximal tubule epithelial cells (HK-2). OTA showed dose-dependent increase in cytotoxicity (IC₅₀ = 161 nM, p<0.05) at 48 h, while treatment up to 2 mM α-tocopherol did not change cell viability. Levels of the reduced form of glutathione (GSH) were decreased with α-tocopherol treatment, although the ratio of the oxidative form (GSSG) to GSH remained the same. Among several genes associated with oxidative stress, expression of superoxide dismutase 1 (SOD1), catalase (CAT), glutathione reductase (GSR), and kidney injury molecule-1 (KIM-1) were significantly up-regulated by OTA treatment. CAT and GSR showed decreased expression at 0.5 - 2 mM α-tocopherol and OTA at IC₅₀ value, KIM-1 was decreased at 0.5 mM α-tocopherol and OTA at IC₅₀ value, and nuclear factor erythroid 2-related factor 2 (Nrf2) was decreased at 0.5 - 1 mM α-tocopherol and OTA at IC₅₀ value. In addition, the levels of malondialdehyde (MDA) were increased significantly by OTA while significantly decreased by α-tocopherol. The results show that α-tocopherol may alleviate potential OTA-induced renal damage and oxidative stress through reducing cytotoxicity and enhancing the antioxidant defense systems.

Au@SiO2 SERS nanotags based lateral flow immunoassay for simultaneous detection of aflatoxin B1 and ochratoxin A

Agricultural products are frequently contaminated by mycotoxins. Multiplex, ultrasensitive, and rapid determination of mycotoxins is still a challenging problem, which is of great significance to food safety and public health. Herein, a surface-enhanced Raman scattering (SERS) based lateral flow immunoassay (LFA) for the simultaneous on-site determination of aflatoxin B₁ (AFB₁) and ochratoxin A (OTA) on the same test line (T line) was developed, in this study. In practice, two kinds of Raman reporters 4-mercaptobenzoic acid (4-MBA), and 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) encoded silica-encapsulated gold nanotags (Au^4-MBA@SiO₂ and Au^DNTB@SiO₂) were used as detection markers to identify the two different mycotoxins. Through systematic optimization of the experimental conditions, this biosensor has high sensitivity and multiplexing with the limits of detection (LODs) at 0.24 pg mL^-1 for AFB₁ and 0.37 pg mL^-1 for OTA. These are far below the regulatory limits set by the European Commission, in which the minimum LODs for AFB₁ and OTA are 2.0 and 3.0 μg kg^-1. In the spiked experiment, the food matrix are corn, rice, and wheat, and the mean recoveries of the two mycotoxins ranged from 91.0% ± 6.3%-104.8% ± 5.6% for AFB₁ and 87.0% ± 4.2%-112.0% ± 3.3% for OTA. These results demonstrate that the developed immunoassay has good stability, selectivity, and reliability, which can be used for routine monitoring of mycotoxin contamination.

Mycotoxins and cellular senescence: the impact of oxidative stress, hypoxia, and immunosuppression

Mycotoxins induce oxidative stress, hypoxia, and cause immunosuppressive effects. Moreover, emerging evidence show that mycotoxins have a potential of inducing cellular senescence, which are involved in their immunomodulatory effects. Mycotoxins upregulate the expression of senescence markers γ-H2AX, senescence-associated β-galactosidase, p53, p16, and senescence-associated secretory phenotype (SASP) inflammatory factors. Moreover, mycotoxins cause senescence-associated cell cycle arrest by diminishing cyclin D₁ and Cdk4 pathways, as well as increasing the expression of p53, p21, and CDK6. Mycotoxins may induce cellular senescence by activating reactive oxygen species (ROS)-induced oxidative stress. In addition, hypoxia acts as a double-edged sword on cell senescence; it could both act as the stress-induced senescence and also hinder the onset of cellular senescence. The SASP inflammatory factors have the ability to induce an immunosuppressive environment, while mycotoxins directly cause immunosuppression. Therefore, there is a potential relationship between mycotoxins and cellular senescence that synergistically cause immunosuppression. However, most of the current studies have involved the effect of mycotoxins on cell cycle arrest, but only limited in-depth research has been carried out to link the occurrence of this condition (cell cycle arrest) with cellular senescence.

Ochratoxin A induces endoplasmic reticulum stress and fibrosis in the kidney via the HIF-1α/miR-155-5p link

Ochratoxin A (OTA) is a ubiquitous fungal toxin found in agricultural products and foods that is toxic to both humans and animals. OTA mainly affects kidney, but the mechanisms underlying OTA-induced nephrotoxicity remain not fully understood. MicroRNA (miRNA) is involved in key cellular processes. The toxic mechanism and regulatory effects of miRNAs on OTA toxicity in kidney, and particularly the role of HIFα-1/miR-155-5p on OTA-caused ER stress and fibrosis, were investigated in this study. OTA induced hypoxia-like conditions such as ER stress and fibrosis in HK-2 cells and renal tissues via modulating HIF-1α, which was followed by regulation of ER stress-related proteins (GRP78 and ATF-4), as well as fibrosis-related markers (fibronectin, α-SMA, and E-cadherin). Notably, a total of 62 miRNAs showed significant differential expression in kidney of OTA-treated mice. Under OTA exposure, HIF-1α enhanced miR-155-5p expression, causing ER stress and fibrosis in HK-2 cells. HIF-1α knockdown decreased OTA-induced miR-155-5p expression as well as ER stress and fibrotic responses, whereas miR-155-5p overexpression restored this. Our data suggest that OTA enhances ER stress and fibrosis in the kidney through upregulating the HIF-1α/miR-155-5p link.

Research progress of ochratoxin a bio-detoxification

Ochratoxins (OTs) is an extremely toxic mycotoxin in which Ochratoxin A (OTA) is the most toxic and prevalent in the ochratoxin family. OTA is among the five most critical mycotoxins that are subject to legal regulations. Animals and humans may be exposed to OTA through dietary intake, inhalation, and dermal contact. OTA is considered nephrotoxic, genotoxic, cytotoxic, teratogenic, carcinogenic, mutagenic, immunotoxic, and myelotoxic. So, intake of OTA contaminated foods and feeds can impact the productivity of animals and health of people. According to this review, several studies have reported on the approaches that have been established for OTA removal. This review focused on the control approaches to mitigate OTA contamination, OTA bio-detoxification materials and their applicable techniques, recombinant strains for OTA bio-detoxification, and their detoxification effects, recombinant OTA-degrading enzymes and their sources, recombinant fusion enzymes for OTA, ZEN and AFB1 mycotoxins detoxification, as well as the current application and commercialized OTA bio-detoxification products. However, there is no single technique that has been approved to detoxify OTA by 100% to date. Some preferred current strategies for OTA bio-detoxification have been recombinant degrading enzymes and genetic engineering technology due to their efficiency and safety. Therefore, prospective studies should focus on standardizing pure enzymes from genetically engineered microbial strains that have great potential for OTA detoxification.

Innovations and developments in single cell protein: Bibliometric review and patents analysis

Background

Global demand for food products derived from alternative proteins and produced through sustainable technological routes is increasing. Evaluation of research progress, main trends and developments in the field are valuable to identify evolutionary nuances.

Methods

In this study, a bibliometric analysis and search of patents on alternative proteins from fermentation processes was carried out using the Web of Science and Derwent World Patents Index^™ databases, using the keywords and Boolean operators "fermentation" AND "single cell protein" OR "single-cell protein." The dataset was processed and graphics generated using the bibliometric software VOSviewer and OriginPro 8.1.

Results

The analysis performed recovered a total of 360 articles, of which 271 were research articles, 49 literature review articles and 40 publications distributed in different categories, such as reprint, proceedings paper, meeting abstract among others. In addition, 397 patents related to the field were identified, with China being the country with the largest number of publications and patents deposits. While this topic is largely interdisciplinary, the majority of work is in the area of Biotechnology Applied Microbiology, which boasts the largest number of publications. The area with the most patent filings is the food sector, with particular emphasis on the fields of biochemistry, beverages, microbiology, enzymology and genetic engineering. Among these patents, 110 are active, with industries or companies being the largest depositors. Keyword analysis revealed that the area of study involving single cell protein has included investigation into types of microorganisms, fermentation, and substrates (showing a strong trend in the use of agro-industrial by-products) as well as optimization of production processes.

Conclusion

This bibliometric analysis provided important information, challenges, and trends on this relevant subject.

From Grapes to Wine: Impact of the Vinification Process on Ochratoxin A Contamination

Ochratoxin A (OTA) is one of the major mycotoxins, classified as "potentially carcinogenic to humans" (Group 2B) by the International Agency for Research on Cancer (IARC), and wine is one of its main sources of intake in human consumption. The main producer of this toxin is Aspergillus carbonarius, a fungus that contaminates grapes early in the growing season. The vinification process, as a whole, reduces the toxin content in wine compared to the grapes; however, not all vinification steps contribute equally to this reduction. During the maceration phase in red wines, toxin concentrations generally tend to increase. Based on previous studies, this review provides an overview of how each step of the vinification process influences the final OTA contamination in wine. Moreover, certain physical, chemical, and microbiological post-harvest strategies are useful in reducing OTA levels in wine. Among these, the use of fining agents, such as gelatin, egg albumin, and bentonite, must be considered. Therefore, this review describes the fate of OTA during the winemaking process, including quantitative data when available, and highlights actions able to reduce the final OTA level in wine.

Enzymatic degradation of ochratoxin A in the gastrointestinal tract of piglets

Animal feeds are often contaminated with ochratoxin A (OTA), a potent natural mycotoxin hazardous to animal and human health that accumulates in blood and tissues. To the best of our knowledge, this study is the first to investigate the in vivo application of an enzyme (OTA amidohydrolase; OAH) that degrades OTA into the nontoxic molecules phenylalanine and ochratoxin α (OTα) in the gastrointestinal tract (GIT) of pigs. Piglets were fed six experimental diets over 14 days, varying in OTA contamination level (50 or 500 μg/kg; OTA50 and OTA500) and presence of OAH; a negative control diet (no OTA added) and a diet containing OTα at 318 µg/kg (OTα318). The absorption of OTA and OTα into the systemic circulation (plasma and dried blood spots, DBS), their accumulation in kidney, liver, and muscle tissues, and excretion through feces and urine were assessed. The efficiency of OTA degradation in the digesta content of the GIT was also estimated. At the end of the trial, accumulation of OTA in blood was significantly higher in OTA groups (OTA50 and OTA500) in comparison to enzyme groups (OAH50 and OAH500, respectively). The supplementation of OAH explicitly reduced the absorption of OTA (P < 0.005) into plasma by 54% and 59% (from 40.53 ± 3.53 to 18.66 ± 2.28 ng/mL in piglets fed the 50 μg OTA/kg diets and from 413.50 ± 71.88 to 168.35 ± 41.02 ng/mL in piglets fed the 500 μg OTA/kg diets, respectively) and in DBS by 50% and 53% (from 22.79 ± 2.63 to 10.67 ± 1.93 ng/mL in piglets fed the 50 μg OTA/kg diets and from 232.85 ± 35.16 to 105.71 ± 24.18 ng/mL in piglets fed the 500 μg OTA/kg diets, respectively). The OTA concentrations in plasma were positively associated with the OTA levels detected in all tissues analyzed; adding OAH reduced OTA levels in the kidney, liver, and muscle (P < 0.005) by 52%, 67%, and 59%, respectively. The analysis of GIT digesta content showed that OAH supplementation led to OTA degradation in the proximal GIT where natural hydrolysis is inefficient. Overall, the data of present in vivo study demonstrated that supplementation of swine feeds with OAH successfully reduced OTA levels in blood (plasma and DBS) as well as in kidney, liver, and muscle tissues. Therefore, an approach to use enzymes as feed additives might be most promising to mitigate the harmful effects of OTA on the productivity and welfare of pigs and at the same time improving the safety of pig-derived food products.

Aptamer-based NanoBioSensors for seafood safety

Chemical and biological contaminants are of primary concern in ensuring seafood safety. Rapid detection of such contaminants is needed to keep us safe from being affected. For over three decades, immunoassay (IA) technology has been used for the detection of contaminants in seafood products. However, limitations inherent to antibody generation against small molecular targets that cannot elicit an immune response, along with the instability of antibodies under ambient conditions greatly limit their wider application for developing robust detection and monitoring tools, particularly for non-biomedical applications. As an alternative, aptamer-based biosensors (aptasensors) have emerged as a powerful yet robust analytical tool for the detection of a wide range of analytes. Due to the high specificity of aptamers in recognising targets ranging from small molecules to large proteins and even whole cells, these have been suggested to be viable molecular recognition elements (MREs) in the development of new diagnostic and biosensing tools for detecting a wide range of contaminants including heavy metals, antibiotics, pesticides, pathogens and biotoxins. In this review, we discuss the recent progress made in the field of aptasensors for detection of contaminants in seafood products with a view of effectively managing their potential human health hazards. A critical outlook is also provided to facilitate translation of aptasensors from academic laboratories to the mainstream seafood industry and consumer applications.

Electrochemiluminescence Aptasensor Based on Gd(OH)3 Nanocrystalline for Ochratoxin A Detection in Food Samples

In the present study, the electrochemiluminescence (ECL) properties of Gd(OH)₃ nanocrystals with K₂S₂O₈ as the cathode coreactant were studied for the first time. Based on the prominent ECL behavior of this material and the excellent specificity of the aptamer technique, an ECL aptasensor for the detection of ochratoxin A (OTA) was formulated successfully. Over an OTA concentration range of 0.01 pg mL^-1 to 10 ng mL^-1, the change in the ECL signal was highly linear with the OTA concentration, and the limit of detection (LOD) was 0.0027 pg mL^-1. Finally, the ECL aptasensor was further used to detect OTA in real samples (grapes and corn) and satisfactory results were obtained, which indicated that the built method is expected to be applied in food detection.

Aptamer Molecular Beacon Sensor for Rapid and Sensitive Detection of Ochratoxin A

Ochratoxin A (OTA) is a carcinogenic fungal secondary metabolite which causes wide contamination in a variety of food stuffs and environments and has a high risk to human health. Developing a rapid and sensitive method for OTA detection is highly demanded in food safety, environment monitoring, and quality control. Here, we report a simple molecular aptamer beacon (MAB) sensor for rapid OTA detection. The anti-OTA aptamer has a fluorescein (FAM) labeled at the 5' end and a black hole quencher (BHQ1) labeled at the 3' end. The specific binding of OTA induced a conformational transition of the aptamer from a random coil to a duplex-quadruplex structure, which brought FAM and BHQ1 into spatial proximity causing fluorescence quenching. Under the optimized conditions, this aptamer sensor enabled OTA detection in a wide dynamic concentration range from 3.9 nM to 500 nM, and the detection limit was about 3.9 nM OTA. This method was selective for OTA detection and allowed to detect OTA spiked in diluted liquor and corn flour extraction samples, showing the capability for OTA analysis in practical applications.

Mycotoxins in soybean-based foods fermented with filamentous fungi: Occurrence and preventive strategies

Fermented soybean products are widely consumed worldwide, and their popularity is increasing. Filamentous fungi, such as Actinomucor, Aspergillus, Monascus, Mucor, Penicillium, Rhizopus, and Zymomonas, play critical roles in the fermentation processes of many soybean foods. However, besides producing essential enzymes for food fermentation, filamentous fungi can release undesirable or even toxic metabolites into the food. Mycotoxins are toxic secondary metabolites produced by certain filamentous fungi and may be detected during the food production process. Without effective prevention strategies, mycotoxin contamination in fermented soybean products poses a risk to human health. This review focused on the changes in mycotoxigenic fungal abundance and mycotoxin contamination at different stages during the production of soybean-based fermented foods, as well as effective strategies for preventing mycotoxin contamination in such products. Data from relevant studies demonstrated a tendency of change in the genera of mycotoxigenic fungi and types of mycotoxins (aflatoxins, alternariol, alternariol monomethyl ether, deoxynivalenol, fumonisins, ochratoxin A, rhizoxins, T-2 toxin, and zearalenone) present in the raw materials and the middle and final products. The applicability of traditional chemical and physical mitigation strategies and novel eco-friendly biocontrol approaches to prevent mycotoxin contamination in soybean-based fermented foods were discussed. The present review highlights the risks of mycotoxin contamination during the production of fermented soybean products and recommends promising strategies for eliminating mycotoxin contamination risk in soybean-based fermented foods.

Inhibition of cytochrome P450 enhances the nephro- and hepatotoxicity of ochratoxin A

The mycotoxin ochratoxin A (OTA) is a contaminant in food that causes nephrotoxicity and to a minor degree hepatotoxicity. Recently, we observed that OTA induces liver damage preferentially to the cytochrome P450 (CYP)-expressing pericentral lobular zone, similar to hepatotoxic substances known to be metabolically toxified by CYP, such as acetaminophen or carbon tetrachloride. To investigate whether CYP influences OTA toxicity, we used a single dose of OTA (7.5 mg/kg; intravenous) with and without pre-treatment with the pan CYP-inhibitor 1-aminobenzotriazole (ABT) 2 h before OTA administration. Blood, urine, as well as liver and kidney tissue samples were collected 24 h after OTA administration for biochemical and histopathological analyses. Inhibition of CYPs by ABT strongly increased the nephro- and hepatotoxicity of OTA. The urinary kidney damage biomarkers kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) were increased > 126-fold and > 20-fold, respectively, in mice treated with ABT and OTA compared to those receiving OTA alone. The blood biomarkers of liver damage, alanine transaminase (ALT) and aspartate transaminase (AST) both increased > 21- and 30-fold, respectively, when OTA was administered to ABT pre-treated mice compared to the effect of OTA alone. Histological analysis of the liver revealed a pericentral lobular damage induced by OTA despite CYP-inhibition by ABT. Administration of ABT alone caused no hepato- or nephrotoxicity. Overall, the results presented are compatible with a scenario where CYPs mediate the detoxification of OTA, yet the mechanisms responsible for the pericental liver damage pattern still remain to be elucidated.