Ochratoxin Research Articles

HPLC-MS/MS and ICP-MS for Evaluation of Mycotoxins and Heavy Metals in Edible Insects and Their Defatted Cakes Resulting from Supercritical Fluid Extraction.

Edible Insects (EIs) are an alternative source of bioactive compounds such as proteins or fatty acids and micronutrients as vitamins or minerals, thus showing potential to replace traditional foodstuffs in an economical and environmentally friendly way. Nonetheless, EIs can accumulate hazardous chemicals such as mycotoxins and heavy metals. The aim of the present study is to determine mycotoxins and heavy metal content in raw insect samples and those resulting products obtained after supercritical fluid extraction (SFE). Insect samples included Acheta domesticus (cricket) meal, Tenebrio molitor (mealworm) meal, Alphitobius diaperinus (buffalo worm), and Locusta migratoria (locust). For this purpose, a QuEChERS method followed by LC-MS/MS analysis was optimized with good results for the analysis of mycotoxins, principally Aflatoxins (AFs), Ochratoxin A (OTA), and Enniatins (ENNs). In contrast, heavy metals (As, Cd, Hg, Pb) were determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The results obtained revealed that Locust was positive for AFG2 at a level of 115.5 μg/kg, and mealworm was only contaminated with OTA at 58.1 μg/kg. Emerging mycotoxins (ENNA, ENNA1, ENNB, and ENNB1) were detected at lower levels < 2.2 µg/Kg. Concerning heavy metals, limits exceeding regulation were detected for Cd in the insect species studied, with levels up to 219 μg/kg, and for Pb in crickets (100.3 μg/kg). Finally, the analysis of the post-extraction solids after SFE processing revealed that heavy metals remained in the resulting SFE cakes, while mycotoxins were detected at negligible levels (up to 1.3 µg/Kg).

Assessment of Fungal and Contamination of Ochratoxin A and Patulin in Foods Susceptible to Contamination in the Yangzhou Market, China

The conducive conditions of warm and humid climates can facilitate mold proliferation and subsequent mycotoxin production during food processing and distribution, thereby posing a potential risk to consumer health. However, there exists a significant lack of research regarding the diversity of molds and the presence of ochratoxin A (OTA) and patulin (PAT) in food products available in the Yangzhou market. This study was conducted to assess OTA contamination levels and fungal presence in 57 cereal-based food samples, as well as PAT contamination levels and fungal presence in 50 types of foods, including apples, hawthorn berries, pears, and their derivatives. Ochratoxin A (OTA) was detected in 17 out of 57 cereal-based food samples, with concentrations ranging from 0.93 to 32.69 μg/kg. The contamination rate was determined to be 31.48%, and no samples exceeded the established regulatory limits. Furthermore, seven apple products were identified as contaminated with patulin (PAT), exhibiting concentrations between 26.85 and 192.78 μg/kg. Additionally, three food samples derived from hawthorn showed PAT contamination levels ranging from 29.83 to 88.56 μg/kg. Through purification on potato dextrose agar (PDA) medium, observation of colony morphology, and analysis of internal transcribed spacer (ITS) sequences, a total of 35 fungal strains belonging to 13 genera were identified in cereal-based foods. The predominant genera in cereals included Talaromyces, Fusarium, Aspergillus, and Penicillium. Additionally, twelve fungal strains from five genera (Penicillium, Cladosporium, Aureobasidium, Curvularia, and Alternaria) were isolated and identified in fruits and their derivatives. The findings indicate that OTA and PAT toxins are one of the important risk factors that threaten consumer health. Furthermore, the contamination of some other toxigenic strains is also a matter of substantial concern, with potential implications for consumer health.

Double detection of mycotoxins based on aptamer induced Fe3O4@TiO2@Ag Core − Shell nanoparticles “turn on” fluorescence resonance energy transfer

Multiple and sensitive mycotoxin detection is an essential early-warning mechanism for safeguarding human health, and preserving the environment. We synthesized a turn-on Fluorescence Resonance Energy Transfer (FRET) aptamer sensor based on the unique fluorescence quenching and substrate recognition characteristics of Ag NTs (energy receptors) and aptamer modified Fe3O4@TiO2 NP (energy donor) to detect multiple toxins using a single diagnostic approach. The addition of aflatoxin B1 (AFB1) and ochratoxin A (OTA) resulted in a change in fluorescence intensity at 510 and 650 nm, which can be employed for simultaneous recognition with detection limits of 0.94 ng·mL−1 (R2 = 0.997) and 0.54 ng·mL−1 (R2 = 0.995). The aptasensors have been successfully applied for the determination of AFB1 and OTA in grain and oil samples with high recovery rates. The approach provides novel possibilities for the development of sensitive and selective aptasensors with potential applications in aptamer-recognized multifunctional biosensing.

Essential oils from Cuminum cyminum and Laurus nobilis and their principal constituents: evaluation of antifungal and antimycotoxigenic potential in Aspergillus species.

The antifungal and antimycotoxigenic activities of the essential oils (EO) from Cuminum cyminum and Laurus nobilis, and their respective principal compounds, cuminaldehyde and 1,8-cineole, were evaluated against fungi of the genus Aspergillus: A.carbonarius, A.niger, A.ochraceus and A.westerdijkiae. The antifungal activity was determined by the contact method and the mycelial growth of the fungi was evaluated. Scanning Electron Microscopic (SEM) images were obtained to suggest modes of action of the compounds analyzed. The antimycotoxigenic activity was determined by HPLC. A.carbonarius was completely inhibited by cumin EO (500 µL L-1), by laurel EO and by cuminaldehyde (5000 µL L-1). The cumin EO (500 µL L-1) completely inhibited the growth of A.niger. All the samples inhibited the mycelial growth of A.ochraceus, especially cumin EO and cuminaldehyde (250 µL L-1). A.westerdijkiae was completely inhibited by cumin EO and cuminaldehyde (1000 µL L-1), by laurel EO and 1,8-cineole (10000 µL L-1). A decrease in the production of ochratoxin A (OTA) was observed post-treatment, except in A. ochraceus, only inhibited by laurel EO. SEM images showed morphological changes in fungal structures and spore inhibition post-treatment. The results confirmed the antifungal and antimycotoxigenic effect of EO and their principal constituents on fungi evaluated.

Smartphone-based dual-mode aptasensor with bifunctional metal-organic frameworks as signal probes for ochratoxin A detection

Ochratoxin A (OTA) poses significant risks to human health, being potentially nephrotoxic, carcinogenic, genotoxic, and immuno-toxic. In this work, we developed a dual-mode aptasensor for OTA analysis, integrating colorimetric, electrochemical, and smartphone-based detection. The bifunctional Fe-MIL-88 metal-organic framework, acting as both a nanozyme capable of catalyzing the 3,3′,5,5′-tetramethylbenzidine substrate and an electrochemical signal amplifier, enabled OTA quantification through current response or changes in color and absorbance intensity. Besides, the spatial confinement effect enhances the local concentration of Fe-MIL-88 signal probes through rolling circle amplification reaction, thereby contributing to a substantial enhancement in sensitivity. The proposed technique is simple, disposable, highly sensitive and selective, enabling OTA detection in the range of 1 fg/mL to 250 ng/mL, with a limit of detection of 0.22 fg/mL (3σ rule). Furthermore, we successfully detected OTA in corn, wheat, and red wine samples, with results good concordance with those obtained using commercial enzyme-linked immunoassay kits.

Presence of Ochratoxin A Residues in Blood Serum of Slaughtered Pigs in Greece.

This study aimed to assess the presence of ochratoxin A (OTA) residues in the blood serum of slaughtered pigs in Greece. Samples were obtained from 1695 healthy slaughtered pigs originating from 113 different farms located in 21 geographic regional units in 8 different geographic regions of Greece and were analyzed using an immunosorbent assay (ELISA) and high-performance liquid chromatography with fluorescence detector (HPLC-FD). OTA contamination assessment showed that 782 (46.1%) and 1233 (72.7%) samples were OTA-positive, with a concentration range of 0.20-5.38 μg/L and 0.15-5.96 µg/L according to ELISA and HPLC-FD analysis, respectively. Also, 88 (77.9%) and 108 (95.6%) of farms were found to be OTA-positive by ELISA and HPLC-FD analysis, respectively. The highest OTA serum positivity rate (>98%) and toxin level (5.96 µg/L) determined by HPLC-FD were observed in the Thessaly region, whereas a high prevalence of up to 100% (range 75-100%) was found on farms in the Crete Island region. The detection of OTA in the serum of slaughtered pigs in different regions in Greece poses a risk for animal and human health and highlights the need for constant OTA monitoring in the swine industry and pork meat production facilities.

Dual improved enzyme-linked immunosorbent assay based on multivalent bifunctional nanobody and polymerized horseradish peroxide for the ultrasensitive detection of Ochratoxin A in coffee samples

Enzyme-linked immunosorbent assay (ELISA) is favored for its high throughput, low cost, and simplicity, but the limited sensitivity of the traditional colorimetric ELISA restricts its wider application. Therefore, developing improvement strategies to enhance its sensitivity is a current research hotspot. In this work, we developed a multivalent bifunctional nanobody (Nb28-C4-SBP) by fusing a nanobody gene (Nb28) against ochratoxin A (OTA) with a self-assembling peptide (C4) and a streptavidin-conjugated peptide (SBP), which can introduce streptavidin-conjugated polymerized horseradish peroxidase (SA-PolyHRP) as a probe into the detection system. Subsequently, a dual improved ELISA (DI-ELISA) was developed using the higher affinity multivalent bifunctional nanobody (Nb28-C4-SBP) and the more enzyme-loaded probe (SA-PolyHRP) for the ultrasensitive detection of OTA in coffee samples. The DI-ELISA demonstrated a detection limit of 1 pg/mL, which was about 20-fold lower than that of the Nb28-C4-SBP and SA-HRP based ELISA and 266-fold lower than that of the Nb28-SBP and SA-PolyHRP based ELISA, respectively. In summary, we developed an ultrasensitive, rapid, and simple immunoassay for detecting OTA in coffee samples. Additionally, the proposed improvement strategy based on multivalent nanobody and polymerized horseradish peroxide is straightforward to operate and holds great potential for enhancing the sensitivity in various immunoassays.

Electrochemiluminescence immunoassay system based on PCN-224-Mn and gold-platinum bimetallic nanoflowers for sensitive detection of ochratoxin A

In this work, a novel Electrochemiluminescence Immunosensor was constructed using PCN-224-Mn and gold-platinum nanoflowers (AuPt NFs) for the ultrasensitive detection of ochratoxin A (OTA). PCN-224 modified with Mn (II) was synthesized as a probe material. The interaction efficiency of PCN-224 with S2O82− was also greatly improved. AuPt NFs were used as the substrate material for the electrodes. It has favorable biocompatibility, large specific surface area and can bind more antigen. Also greatly increased the electroactive surface area and conductivity of the electrode. OTA was detected using a competitive immunoassay strategy, in which OTA in the sample competes with the encapsulated antigen for a finite number of antibodies. ECLIA for the detection of OTA was designed to be highly sensitive, with a linear range from 0.0002 ng mL−1 to 1000 ng mL−1 and a LOD as low as 0.067 pg mL−1. In addition, it was evident from the electrochemical analyses that PCN-224-Mn had a stronger and more stable ECL signal compared to the plain PCN-224. The successful preparation of specific, sensitive and reproducible ECL immunosensors confirms the great promise for the detection of OTA or other small molecule mycotoxins.

CRISPR/Cas12a-Based Indirect Competitive Enzyme-Linked Immunosorbent Assay for Sensitive Detection of Ochratoxin A.

The high toxicity and widespread contamination of ochratoxin A (OTA) make it urgent to develop a sensitive method to detect trace OTA in complex food matrices. Herein, an indirect competitive enzyme-linked immunosorbent assay (icELISA)-based on the CRISPR/Cas12a system is described. DNA amplicons with multiple activation sequences of the CRISPR/Cas12a system were pre-prepared to improve detection sensitivity. In the absence of OTA, streptavidin-mediated biotinylated DNA amplicons were captured by the biotinylated secondary antibody on the microplate. The captured DNA amplicons activated the CRISPR/Cas12a system, which thereby effectively cleaved the reporter DNA, producing strong fluorescence. The presence of OTA led to a decrease in DNA amplicons on the microplate, resulting in a decrease in activated Cas12a and ultimately a drop in fluorescence intensity. OTA in food matrices at nanogram per milliliter levels can be detected. Therefore, the new method has great potential in monitoring OTA.

EGCG alleviates Ochratoxin A-induced pyroptosis in rat's kidney by inhibiting NLRP3/Caspase-1/GSDMD signaling pathway

Ochratoxin A (OTA) exposure is inevitable due to its contamination in foods, and there is no treatment for the OTA induced organ toxicity. We evaluate the effect of epigallocatechin gallate (EGCG) on the nephrotoxicity caused by OTA, and to reveal the relationship of this effect with the NLRP3/Caspase-1/GSDMD pathway dependent pyroptosis. 40 male Wistar albino rats divided into 5 groups (n = 8, per group) 0.5 mg/kg/day OTA were administered to the rats and 50 mg/kg and 100 mg/kg EGCG were administered to the groups by gavage orally for 14 days. Serum urea and creatinine levels increased significantly with OTA exposure. Similarly, it was determined that significant changes in oxidative stress parameters with OTA exposure in kidney tissue. Also, there was a significant increase in kidney tissue TGF-β, NF-κB, IL-1β, IL-18, NLRP3, Caspase-1 and GSDMD mRNA expressions with OTA exposure. EGCG administration augmented a dose-dependent decrease in the aforementioned parameters. NLRP3/Caspase-1/GSDMD pathway is induced in the kidneys due to OTA exposure were shown with this study. Potent antioxidant EGCG could alleviate the pathways specified with this study in OTA nephrotoxicity and its supplementation may be effective strategies for the protection.

Phytochemical Characterization of Bilberries and Their Potential as a Functional Ingredient to Mitigate Ochratoxin A Toxicity in Cereal-Based Products.

Mycotoxin contamination of cereals and cereal-based products is a serious problem for food safety. Antioxidant-rich ingredients such as bilberries (Vaccinium myrtillus L., VM) may mitigate their harmful effects. Firstly, total phenolic content, antioxidant activity, and analytical phytochemical composition (hydroxycinnamic and hydroxybenzoic acids, flavanols, flavonols, and anthocyanins) were assessed in lyophilized wild bilberries from Romania. Secondly, this study evaluated bilberries' effects on reducing ochratoxin A (OTA) bioaccessibility and cytotoxicity. An in vitro digestion model was developed and applied to four different types of bread: Control, VM (2%), OTA (15.89 ± 0.13 mg/kg), and OTA (16.79 ± 0.55 mg/kg)-VM (2%). The results indicated that VM decreased OTA bioaccessibility by 15% at the intestinal level. OTA-VM digests showed improved Caco-2 cell viability in comparison to OTA digests across different exposure times. Regarding the alterations in Jurkat cell line cell cycle phases and apoptosis/necrosis, significant increases in cell death were observed using OTA digests (11%), while VM addition demonstrated a protective effect (1%). Reactive oxygen species (ROS) analysis confirmed these findings, with OTA-VM digests showing significantly lower ROS levels compared to OTA digests, resulting in a 3.7-fold decrease. Thus, bilberries exhibit high potential as a functional ingredient, demonstrating protection in OTA mitigation effects.

First evidence on the occurrence of multi-mycotoxins and dietary risk exposure to AFB1 along the cassava value chain in Uganda

This study investigated the occurrence and distribution of multiple mycotoxins (aflatoxin B1, B2, G1, G2, fumonisins B1, B2, ochratoxin A (OTA), deoxynivalenol (DON), zearalenone (ZEN), and citrinin (CIT)) in cassava products and as assessed the potential risk of aflatoxin B1 (AFB1) exposure among cassava consumers. A total of 192 samples of cassava products (96 flour and 96 chips, each with 48 samples from farmer and 48 from wholesaler) were analysed using LC/MS–MS. All positive samples irrespective of their origin (flour or chips) exhibited AFB1 levels exceeding the EU regulatory threshold of 5 µg/kg. The sum of fumonisins (FB1 + FB2), ZEN, and DON were significantly (P < 0.05) higher in cassava flour (14.3 µg/kg; 3.71 µg/kg; 25.1 µg/kg) compared to chips (6.54 µg/kg; 1.25 µg/kg; 0.25 µg/kg), respectively. Aflatoxins G2 was not detected in any of 192 samples. Cassava flour samples from farmers exhibited significantly (P < 0.05) higher mean concentrations of AFB1 (27.1 µg/kg), total aflatoxins (78.2 µg/kg), and ochratoxin A (79.6 µg/kg) in contrast to wholesalers, whose mean levels were notably lower at 8.91, 5.79 µg/kg, and 2.44 µg/kg, respectively, pointing the likely critical source of mycotoxin contamination. Cassava consumers in Northern Uganda are at a higher risk, with an estimated 2.06 cancer cases per 100,000 individuals per year compared to those in Eastern Uganda at 0.25. This study underscores the urgent need for interventions to manage aflatoxins in cassava flour, particularly at farm level in Northern Uganda. It accentuates a shift market to household-level sampling and the need for analytical methods targeting multiple mycotoxins.

Ameliorating Effect of Grape (Vitis vinifera L.) Seed and Peel Extracts with Selenium on Ochratoxin-A Exposed Renal Dysfunction in Male Wistar Rats

Background and AimDrug-induced nephrotoxicity is extensively documented as the initial stage of kidney disease that particularly results in acute renal injury and chronic renal dysfunction. The single and combined effect of grape peel extract (GPE), grape seed extracts (GSE) and selenium (Sel) were investigated in current study for controlling of renal injury induced by Ochratoxin-A (OTA) in male rats. MethodsForty nine male Wistar rats weighing 200 ± 10 g were injected with OTA (0.5 mg/kg bw) to induce nephrotoxicity, then treated with singleand combined applications of GSE, GPE and Sel. In addition, the OTA induced nephrotoxicity rats were screened for various biological and physiological parameters like food ingestion, body weight gain, liver weight, serum kidney biomarkers, serum lipid fractions, enzymatic and non-enzymatic lipid peroxidation indicators and histopathological studies. ResultsOur findings suggested that the combination of GSE 2 % and Sel (50–50) treatment reduced renal dysfunction in OTA-induced rats by significantly lowering lipid peroxidation indicators, lipid and kidneys profiles and enhancing enzymatic and non-enzymatic antioxidants biomarkers followed by GSE 2 % then Selenium (0.4 mg/kg) in OTA. Histological analysis of the kidney revealed more severe renal tubule degeneration in OTA-induced rats, While GSE and GPE combonation showed only moderate glomerular tuft enlargement and minimal renal tubule deterioration. Furthermore, the combination of GSE 2 %+Sel (50–50) revealed normal histological structure. ConclusionsGrape seed extracts along with selenium mightbe used as dietary supplements to reduce renal toxicity induced by chemicals or compounds that cause nephrotoxicity.

Evaluating dietary exposure and risk characterization of aflatoxin B1, citrinin, and ochratoxin A co-occurrence in pigmented rice consumed in Thailand

In recent years, pigmented rice, often referred to as functional rice, has attracted increasing attention due to its perceived health benefits arising from an abundance of phytochemicals. However, there is limited information on the occurrence and risks of mycotoxins due to long-term consumption of pigmented rice. This study assessed the co-occurrence and contamination levels of aflatoxins, citrinin (CIT), and ochratoxin A (OTA) in various pigmented rice samples sourced from Thailand, and also evaluated the potential health risks for consumers. The results indicated varying levels of mycotoxin contamination among the different tested pigmented rice varieties, with aflatoxin B1 (AFB1) being the most prevalent (39.1 %), followed by CIT (17.3 %) and OTA (14.5 %). The co-occurrences of AFB1-CIT and CIT-OTA were the most prevalent combination observed in the pigmented rice samples. Although the AFB1 and CIT levels remained below regulatory limits, some samples had OTA levels exceeding these limits, though by a small percentage. Furthermore, the anthocyanin content in pigmented rice showed a weak positive correlation with the AFB1 level (p < 0.05). The estimated risk of liver cancer incidence associated with the consumption of pigmented rice containing AFB1 was in the range 0.012–0.061 cases/100,000 persons/year, depending on consumption rate and behavior. The risk posed by CIT exposure was considered negligible. However, the exposure assessments suggested a potential risk of OTA exposure, particularly in scenarios with higher consumption rates. Cumulative risk assessment of AFB1-OTA co-occurrence indicated an amplified health risk compared to single mycotoxin exposure. These findings offer valuable evidence, encouraging further research aimed at mitigating the risks associated with mycotoxin contamination in pigmented rice.

Biomonitoring and determinants of mycotoxin exposures from pregnancy until post-lactation in HIV-infected and HIV-uninfected women from Harare, Zimbabwe

The human immunodeficiency virus (HIV) heavily affects women from resource-limited settings who are vulnerable to potentially harmful mycotoxins including aflatoxin B1 (AFB1), fumonisin B1 (FB1) and ochratoxin A (OTA). We aimed to conduct biomonitoring and ascertain the determinants of maternal mycotoxin exposure in pregnancy, lactation and post-lactation periods. We conducted a retrospective longitudinal study in HIV-infected and HIV-uninfected women from Harare, Zimbabwe. 175 and 125 random urine samples in pregnancy and 24 months after delivery (post-lactation) respectively were analysed for aflatoxin M1 (AFM1) and FB1 by ELISA. 6 weeks after delivery (lactation), 226 and 262 breast milk (BM) samples were analysed for AFM1 and OTA respectively by ELISA. The association of demographics and food consumption with mycotoxins was evaluated using multivariable logistic regression. In HIV-infected, urinary AFM1 was detected in 46/94 (Median: 0.05; Range: 0.04–0.46 ng mL−1) in pregnancy and 47/66 (Median: 0.05; Range: 0.04–1.01 ng mL−1) post-lactation. Urinary FB1 was detected in 86/94 (Median: 1.39; Range: 0.17–6.02 ng mL−1) in pregnancy and 56/66 (Median: 0.72; Range: 0.20–3.81 ng mL−1) post-lactation. BM AFM1 was detected in 28/110 (Median: 7.24; Range: 5.96–29.80 pg mL−1) and OTA in 11/129 (Median: 0.20; Range: 0.14–0.65 ng mL−1). In HIV-uninfected, urinary AFM1 was detected in 48/81 (Median: 0.05; Range: 0.04–1.06 ng mL−1) in pregnancy and 41/59 (Median: 0.05; Range: 0.04–0.52 ng mL−1) post-lactation. Urinary FB1 was detected in 74/81 (Median: 1.15; Range: 0.17–6.16 ng mL−1) in pregnancy and 55/59 (Median: 0.96; Range: 0.20–2.82 ng mL−1) post-lactation. BM AFM1 was detected in 38/116 (Median: 7.70; Range: 6.07–31.75 pg mL−1) and OTA in 4/133 (Median: 0.24; Range: 0.18–0.83 ng mL−1). Location, wealth, and peanut butter consumption were determinants of AFB1 exposure. HIV infection, BMI, location, rainy season, unemployment, and age were determinants of FB1 exposure. Women especially those pregnant and/or HIV-infected are at risk of adverse effects of mycotoxins.

DNA template triggered copper nanoparticles generation coupled with hybridization chain reaction amplification for simultaneous detection of three mycotoxins in food samples

The co-occurrence of various mycotoxins in food, resulting from fungal infections, can lead to increased toxicity and enhanced harm through synergistic effects. In this work, a fluorescent assay was developed for simultaneous detection of zearalenone (ZEN), ochratoxin A (OTA) and aflatoxin B1 (AFB1) to address the issue of multiple mycotoxins co-contamination. Specific DNA hairpin-based aptamers were employed to recognize the mycotoxins and form a double-stranded DNA structure. Exonuclease III was introduced for the DNA cleavage, releasing single-stranded DNA triggers that could activate the assembling of DNA quadrilateral template. Copper nanoparticles were generated on the frame of DNA quadruplex template and produced fluorescent detection signals, while two hybridization chain reactions occurring on the different branches of the template and provided two additional detection signals. Inadequately reacted DNA chains were efficiently adsorbed and eliminated by Fe3O4@graphene oxide through magnetic separation. The limits of detection and linear ranges for ZEN, AFB1 and OTA were determined as 0.008 ng/mL, 0.003 ng/mL, 0.006 ng/mL and 0.010–100.000 ng/mL, 0.010–100.000 ng/mL, 0.010–50.000 ng/mL, respectively. Moreover, successful verification for real samples yielded recoveries from 99.2% to 102.7%, with a relative standard deviation of <5.23%. Artificially prepared toxic fungus infected samples were also analyzed. This method has demonstrated practical implications for the monitoring of food contaminants.

Decontamination of ochratoxin A from raisins by different processes: evaluation of efficiency and quality attributes

SummaryIn this research, the effects of washing treatments (potassium carbonate (PC), potassium hydroxide (PH), peracetic acid (PA), alkaline hydrogen peroxide (AHP)), ultrasound (US) and high‐intensity pulsed light (HIPL) technologies on the removal of ochratoxin A (OTA) residues in raisins were investigated. PC at 5 min (66.60%), PH at 10 min (65.25%), alkaline hydrogen peroxide at 5 min (63.30%) and HIPL at 12 J cm−2 (62.50%) were found to be the most successful applications in OTA degradation, respectively. Although the OTA degradation rate was high after chemical washing for 10 min, the raisins had a chemical odour. The results show that HIPL effectively reduces OTA levels in raisins without causing any quality loss.

Investigating the Ochratoxin Production Potential of Aspergillus spp in Indian Rice: A Comprehensive Study

Rice (Oryza sativa), world’s second most important cereal crop and most commonly consumed grains in the world. Though more than 100,000 species of fungi are known to exist, majority of mycotoxigenic fungi belong to the species of Aspergillus, Penicillium, and Fusarium. Among Aspergillus spp, Aspergillus niger and Aspergillus ochraceus are known to produce Ochratoxin A (OTA), a notable mycotoxin having adverse effects due to ubiquitous presence, renal toxicity and lengthy persistence. Totally eighty-one samples including unpolished (n = 36) and polished rice samples (n = 45) were collected in various districts of Tamil Nadu to identify ochratoxigenic fungi particularly Aspergillus spp. Out of 81 samples, 62 % (50/81) of samples including unpolished (n = 24) and polished rice (n = 26) documented the occurrence of ochratoxigenic fungi. Extraction of OTA was carried out by agar plug method and the ability of fungus to produce OTA was quantified by RP HPLC-FLD analysis. Among the fungal genera, Aspergillus spp (80 %) recorded the predominant fungus in rice. Molecular confirmation of ochratoxigenic fungi A. niger and A. ochraceus isolates was performed by 18s rDNA analysis. OTA producing ability by RP HPLC-FLD analysis revealed A. ochraceus of section Circumdati recorded the highest OTA production than A. niger isolates of section Nigri. The concentration range of OTA by A. ochraceus vary between 12.33 - 196.84 ng/g and 0.18 - 2.82 ng/g respectively in A. niger isolates. Among the A. ochraceus isolates, potent isolate AO 9 documented the highest OTA production (196.84 ng/g) followed by AO 6 (104.74 ng/g). Similarly, in A. niger AN 1 showed highest production of 2.82 ng/g followed by AN 5 isolate (1.25 ng/g) respectively. The objective of the study is to determine and quantify the ochratoxin production potential of Aspergillus spp in Indian rice by RP HPLC-FLD analysis. The occurrence of Aspergillus spp in rice and the subsequent ochratoxin production raise concern about possible health risk to animal and human environment upon consumption. Hence there is need for improved storage practices and regular monitoring to prevent the prevalence of Aspergillus fungus and OTA contamination in rice supply chain.

Investigation of the mechanisms behind ochratoxin A-induced cytotoxicity in human astrocytes and the protective effects of N-acetylcysteine.

Ochratoxin A (OTA) is a type of mycotoxin commonly found in raw and processed foods. It is essential to be aware of this toxin, as it can harm your health if consumed in high quantities. OTA can induce toxic effects in various cell models. However, a more comprehensive understanding of the harmful effects of OTA on human astrocytes is required. This study evaluated OTA's neurotoxic effects on the Gibco® Human Astrocyte (GHA) cell line, its underlying mechanisms, and the antioxidant N-acetylcysteine (NAC) ability to prevent them. OTA exposure within 5-30 μM has induced concentration-dependent cytotoxicity. In the OTA-treated cells, the levels of reactive oxygen species (ROS) were found to be significantly increased, while the glutathione (GSH) contents were found to decrease considerably. The western blotting of OTA-treated cells has revealed increased Bax, cleaved caspase-9/caspase-3 protein levels, and increased Bax/Bcl-2 ratio. In addition, exposure to OTA has resulted in the induction of antioxidant responses associated with the protein expressions of Nrf2, HO-1, and NQO1. On the other hand, the pretreatment with NAC has partially alleviated the significant toxic effects of OTA. In conclusion, our findings suggest that oxidative stress and apoptosis are involved in the OTA-induced cytotoxicity in GHA cells. NAC could act as a protective agent against OTA-induced oxidative damage.

Identification and Characterization of Multi-Mycotoxins Recovered from Dry Corn in Selected Markets in Enugu Metropolis, Enugu State, Nigeria

Corn is an important food crop that forms a major meal plan in Nigeria. Its high nutritious value also makes it perfect for fungi to thrive and produce its metabolites. Mycotoxin is a fungi metabolite that is toxic to both humans and animals. This study aimed at isolation of fungi from corn vended in selected markets in Enugu metropolis, identification and characterization of mycotoxin produced from the isolates. A total of 9 corn samples were collected from 3 different markets in Enugu metropolis comprising of Emene ,Ogbete and New markets respectively . The samples were cultured on potatoes dextrose agar for isolation, isolates were identified and characterized by cultural, biochemical and microscopic analysis of the organisms; selected isolates were further characterized by polymerase chain reaction (PCR). The isolates were subjected for mycotoxin production by culturing in potatoe dextrose broth for 14 days at 35°C after which the filtrates were assayed for the presence of mycotoxin using gas chromatography-mass spectroscopy (GC-MS) and individual aflatoxins were further characterized using high performance liquid chromatography (HPLC). From the study, Fusarium and Aspergillus flavus occurred at 66% respectively, Aspergillus niger at 55%, Mucor spp at 77%, Penicillium spp at 33%, and Aspergillus fumigates at 44%. PCR amplified products of the selected isolates showed positive amplification at 650bp for internal transcribed spacer gene. Mycotoxins identified from isolates were aflatotoxin, ochratoxin A (OTA), citrinin, patulin, citreoviridin, T-2 toxin, deoxynivalenol (DON), diacetoxyscirpenol, zearalenone (ZEN), nivalenol, Ht-2 toxin, cyclopiazonic acid with ochratoxin A, Diacetoxyscirpenol and Ht-2 toxin being above consumption limit at 2.64ug/kg,1.27ug/kg and 424.48ug/kg respectively. The isolates showed varied concentration of individual aflatoxins comprising of B1, B2, G1 and G2. These aflatoxins were produced by Aspergillus flavus strain ZMXL11, Aspergillus flavus strain AF-13, and Penicillium citrinin PEN-65 among, B1 was found to be above the maximum limit at 99% in all the isolates.Aflatoxin has been found as to be a group 1 carcinogen implicated in liver cancer. Constant consumption of mycotoxin contaminated corn could lead to varying health risk that includes liver cancer, kidney and gastrointestinal disturbances. This study showed that corn sold in selected markets in Enugu metropolis were contaminated with mycotoxigenic fungi that produced high levels of mycotoxin concentrations which is of public health concern.