RESUMEN
Biocontrol Agents (BCAs) can be an eco-friendly alternative to fungicides to reduce the contamination with mycotoxigenic fungi on coffee. In the present study, different strains of bacteria and yeasts were isolated from Ivorian Robusta coffee. Their ability to reduce fungal growth and Ochratoxin A (OTA) production during their confrontation against Aspergillus carbonarius was screened on solid media. Some strains were able to reduce growth and OTA production by 85 % and 90 % and were molecularly identified as two yeasts, Rhodosporidiobolus ruineniae and Meyerozyma caribbica. Subsequent tests on liquid media with A. carbonarius or solely with OTA revealed adhesion of R. ruineniae to the mycelium of A. carbonarius through Scanning Electron Microscopy, and an OTA adsorption efficiency of 50 %. For M. caribbica potential degradation of OTA after 24 h incubation was observed. Both yeasts could be potential BCAs good candidates for Ivorian Robusta coffee protection against A. carbonarius and OTA contamination.
Asunto(s)
Coffea , Lactobacillales , Ocratoxinas , Vitis , Café/metabolismo , Aspergillus/metabolismo , Coffea/microbiología , Levaduras , Vitis/microbiologíaRESUMEN
When onions are improperly stored, a post-harvest disease known as black mold of onion bulbs can result in considerable economic losses. Aspergillus section Nigri, one of many species, has been implicated in the development of black mold. In the present study, rot onion bulbs were collected from markets in Qena, Egypt. Thirteen Aspergillus section Nigri isolates were obtained and identified by morphological and molecular characterization. The ochratoxins potential of isolated A. section Nigri was tested, and three isolates were producers at the range of 1.5-15 ppm. For the presence of pks gene, no amplification product was detected. Using the fungal growth inhibition test, the isolates of A. niger were inhibited by eco-friendly materials Cement and Zeolite. Cement exhibited maximum percentage growth inhibition against the tested isolates at 74.7-86.7%. The pathogenicity activity of the A. niger isolates was tested by inoculation of healthy onion bulbs, other onion bulbs covered with Cement and Zeolite before inoculation by A. niger was used. The two treatments significantly reduced bulbs rot disease of onion than untreated bulbs. Seven and nine isolates showed 0% rot on covered bulbs by Cement and Zeolite, respectively as compared with inoculated onions, which exhibited rot ranging from 55 to 80%. Using eco-friendly materials with efficiency against post-harvest bulbs rot of onion was evaluated in this study.
Asunto(s)
Ocratoxinas , Zeolitas , Cebollas/microbiología , Aspergillus/genética , EgiptoRESUMEN
BACKGROUND: Mycotoxins have been reported to be present in medicinal plants. With the growing usage of medicinal plants, contamination of mycotoxins has emerged as one of the biggest threats to global food hygiene and ecological environment, posing a severe threat to human health. PURPOSE: This study aimed to determine the mycotoxin prevalence and levels in medicinal plants and conduct a risk assessment by conducting a systematic review and meta-analysis. METHODS: A thorough search on Web of Science and PubMed was conducted for the last decade, resulting in 54 studies (meeting the inclusion criteria) with 2829 data items that were included in the meta-analysis. RESULTS: The combined prevalence of mycotoxins in medicinal plants was 1.7% (95% confidence interval, CI = 1.1% - 2.4%), with a mean mycotoxin concentration in medicinal plants of 3.551 µg/kg (95% CI = 3.461 - 3.641 µg/kg). Risk assessment results indicated that aflatoxins and ochratoxin A found in several medicinal plants posed a health risk to humans; additionally, emerging enniatins exhibited possible health risks. CONCLUSION: Therefore, the study underlines the need for establishing stringent control measures to reduce the severity of mycotoxin contamination in medicinal plants.
Asunto(s)
Micotoxinas , Plantas Medicinales , Plantas Medicinales/química , Micotoxinas/análisis , Medición de Riesgo , Humanos , Ocratoxinas/análisis , Contaminación de Alimentos/análisis , Aflatoxinas/análisisRESUMEN
Ochratoxin A (OTA) is a mycotoxin contaminating agricultural products produced by fungi, associated with important toxic effects. Thus, the development of fast, sensitive, and economical approaches for OTA detection is crucial. In this study, a barcode-style lateral flow assay for the semi-quantitative detection of OTA in coffee samples was developed. To achieve this goal, a BSA-OTA complex was immobilized in three test zones to compete with OTA molecules in the sample for binding with anti-OTA antibodies labeled with gold nanoparticles. Different concentrations of OTA in the sample produced distinct colour patterns, allowing semi-quantification of the analyte. The assay exhibited high sensitivity, with a limit of detection of 2.5 µg.L-1, and high reproducibility, with variation coefficient values between 2% and 13%. Moreover, the colour patterns obtained in the analysis with coffee samples were similar to the results obtained with standard OTA solutions, demonstrating a reliable applicability in real samples.
Asunto(s)
Nanopartículas del Metal , Ocratoxinas , Café/química , Oro/química , Reproducibilidad de los Resultados , Contaminación de Alimentos/análisis , Nanopartículas del Metal/química , Ocratoxinas/análisisRESUMEN
The most toxic of the ochratoxins is ochratoxin A (OTA), which is primarily produced by species of Aspergillus and Penicillium that can be found in maize, wheat, coffee, red wine, and various grains. OTA induces immunotoxicity, nephrotoxicity, hepatotoxicity, teratogenicity, and carcinogenicity in both animals and humans. Thus, there is a need to identify mycotoxin detoxification agents that can effectively decontaminate OTA. Seeds of basil (Ocimum basilicum L.), chan (Hyptis suaveolens L.), and chia (Salvia hispanica L.) are functional foods capable of eliminating harmful substances. Despite this potential, the impact of these seeds on OTA detoxification remains unclear. This study reveals that milled basil, chan, and chia seeds adsorb significant levels of OTA, with chia demonstrating the highest adsorption capacity, followed by chan and basil seeds showing the least efficiency. Furthermore, milled basil, chan, and chia seeds effectively reduced OTA residues in artificial gastric and intestinal fluids, where they achieved up to 93% OTA adsorption in the former. In addition, these milled seeds were able to remove OTAs from canned, drip, and instant coffee. This study is the first to report the OTA elimination potential of basil, chan, and chia seeds.
Asunto(s)
Ocratoxinas , Ocimum basilicum , Humanos , Animales , Ocratoxinas/análisis , Café/química , Semillas/químicaRESUMEN
Ochratoxin A (OTA) is a common mycotoxin in food and feed that seriously harms human and animal health. This study investigated the effect of OTA on the muscle growth of juvenile grass carp (Ctenopharyngodon idella) and its possible mechanism in vitro. Our results have the following innovative findings: (1) Dietary OTA increased the expression of increasing phase I metabolic enzymes and absorbing transporters while reducing the expression of efflux transporters, thereby increasing their residue in muscles; (2) OTA inhibited the expressions of cell cycle and myogenic regulatory factors (MyoD, MyoG, and MyHC) and induced ferroptosis by decreasing the mRNA and protein expressions of FTH, TFR1, GPX4, and Nrf2 both in vivo and in vitro; and (3) the addition of DFO improved OTA-induced ferroptosis of grass carp primary myoblasts and promoted cell proliferation, while the addition of AKT improved OTA-inhibited myoblast differentiation and fusion, thus inhibiting muscle growth. Overall, this study provides a potential research target to further mitigate the myotoxicity of OTA.
Asunto(s)
Carpas , Ferroptosis , Enfermedades de los Peces , Ocratoxinas , Animales , Humanos , Suplementos Dietéticos , Inmunidad Innata , Transducción de Señal , Carpas/genética , Carpas/metabolismo , Dieta , Músculos/metabolismo , Alimentación Animal/análisis , Proteínas de Peces/metabolismoRESUMEN
A nucleic acid aptamer based thermally oxidized porous silicon/zinc oxide microarray chip was constructed for the detection of ochratoxin A. The hybrid chains formed by aptamer and complementary chains labeled with fluorescent groups and fluorescent burst groups were used as recognition molecules, and the detection of toxins was accomplished on the chip by the principle of fluorescence signal burst and recovery. The modified QuEChERS method was used for sample pretreatment and the performance of the method was evaluated. The results showed that the linear range was 0.02 â¼ 200 ng/kg with the detection limit of 0.0196 ng/kg under the optimal detection conditions. The method was applied to different cereals with the recoveries of 90.30 â¼ 111.69 %. The developed microarray chip has the advantages of being cost-effective, easy to prepare, sensitive and specific, and can provide a new method for the detection of other toxins.
Asunto(s)
Aptámeros de Nucleótidos , Técnicas Biosensibles , Ácidos Nucleicos , Ocratoxinas , Óxido de Zinc , Silicio , Grano Comestible/química , Porosidad , Zinc , Límite de Detección , Aptámeros de Nucleótidos/genética , Ocratoxinas/análisis , Dióxido de Silicio , Compuestos Orgánicos , Técnicas Biosensibles/métodosRESUMEN
The high toxicity and occurrence of ochratoxin A (OTA) in grains and foods has been a growing concern due to the impacts on health and the economy in many countries. In this sense, simplified devices with high sensitivity and specificity for local monitoring are enthusiastically pursued. In this work, we report for the first time the detection of ochratoxin A in coffee samples using a spoon-shaped waveguide immunosensor. The biosensor was built with the surface of the spoon-shaped waveguide covered by a 60 nm layer of gold to enable the SPR phenomenon. The measurements indicated a linear relationship between the change in the SPR phenomenon values and the OTA concentration in the range from 0.2 ppt to 5 ppt. When analyzed in coffee samples, the biosensor was highly selective and did not suffer matrix interference. The developed biosensor represents a promising analytical device for coffee quality analyses, as it is portable, simple, and suitable for onsite detection of target analytes.
Asunto(s)
Técnicas Biosensibles , Ocratoxinas , Café , Inmunoensayo , Ocratoxinas/análisisRESUMEN
Recently, mycotoxin risks in fermented tea have received high attention, but mycotoxin transfer rates from tealeaf to infusion during brewing were rarely considered. In addition, the assessment data (i.e., mycotoxin occurrences and tea consumption) in previous assessments were usually limited. Here, a comprehensive and cumulative risk assessment of aflatoxins and ochratoxin A was performed using a tea assessment model, by which mycotoxin transfer rates were included and the assessment data were collected worldwide. By 10 times of brewing, the aflatoxin transfer rate was only 2.94% and OTA was 63.65%. Besides the extreme case, hazard quotients (HQs) from all consumers were lower than the threshold of 1.0, indicating no noncarcinogenic risk; the P95 cumulative margin of exposure (1/MoET) values were 2.52E-04 (30-39 years of age) and 2.42E-04 (≥50 years of age) for two high exposure groups under the upper bound scenario, which a little higher than the carcinogenic risk threshold of 1.00E-04. Notably, the P95 cumulative 1/MoET values (3.24E-03 -7.95E-03) by food assessment model were ten times higher than those of by tea assessment model. The comparative results showed that mycotoxin dietary risks on tea consumption by food assessment model were much overestimated. The result of this study indicated that the contaminants transfer rates should be considered for risk assessment on tea consumption in future work.
Asunto(s)
Aflatoxinas , Micotoxinas , Ocratoxinas , Aflatoxinas/toxicidad , Exposición Dietética , Contaminación de Alimentos/análisis , Micotoxinas/toxicidad , Micotoxinas/análisis , Medición de Riesgo , TéRESUMEN
Vasicine from Adhatoda vasica was investigated in the management of aflatoxicosis and ochratoxicosis by in silico molecular docking approach. The computational analysis was carried out using Discovery Studio Autodock 4.5 tool. Absorption, distribution, metabolism, and excretion (ADME), pharmacodynamics and toxicity studies were also carried out using Swiss ADME and PASS online server, respectively. The standard drug compound used was silymarin and the structure were retrieved from the protein data bank for both the test compound vasicine and the standard drug. Vasicine interacted with aflatoxin B1 at 10 different poses and the maximum dock score was found to be 83.04 and the binding energy was -37.54 kcal/mol. Silymarin interacted with aflatoxin B1 at 10 different poses and the maximum dock score was found to be 143.578 and the binding energy was -67.32 kcal/mol. Vasicine interacted with ochratoxin A at 10 different poses and the maximum dock score was found to be 73.75 and the binding energy was -56.20 kcal/mol. Silymarin interacted with ochratoxin A at 10 different poses and the maximum dock score was found to be 89.23 and the binding energy was -98.86 kcal/mol. The compounds possess good gastro intestinal absorption with antioxidant property and exhibits minimum adverse effects. The obtained results support the toxin mitigating potential of the test compound with minimum adverse effects and hence vasicine can be regarded as a potential toxin binder of aflatoxin B1 and ochratoxin A, wherein it can be implemented for alleviating aflatoxicosis and ochratoxicosis.
Asunto(s)
Alcaloides , Género Justicia , Ocratoxinas , Quinazolinas , Silimarina , Animales , Aflatoxina B1/toxicidad , Género Justicia/química , Género Justicia/metabolismo , Simulación del Acoplamiento Molecular , Pollos/metabolismo , Alcaloides/metabolismo , Silimarina/farmacologíaRESUMEN
Aspergillus carbonarius (Bainier) Thom. is an important pathogen and ochratoxin A (OTA) producer in grapes that can be controlled by adopting sustainable approaches. Here we evaluate the application of natural plant extracts as an alternative to synthetic fungicides to reduce OTA contamination and to prevent infection of grapes by two isolates of A. carbonarius. In a preliminary screening, natural extracts of chestnut flower, cistus, eucalyptus, fennel, and orange peel were evaluated for their antifungal and anti-mycotoxigenic efficiency in a grape-based medium at concentrations of 10 and 20 mg/mL. Cistus and orange peel extracts demonstrated the best antifungal activity at both concentrations. Although the eucalyptus extract demonstrated no significant effect on Aspergillus vegetative growth, it significantly reduced OTA by up to 85.75 % at 10 mg/mL compared to the control. Chestnut flower, cistus, eucalyptus, and orange peel extracts were then tested at the lowest concentration (10 mg/mL) for their antifungal activity in artificially inoculated grape berries. The cistus and orange peel extracts demonstrated the greatest antifungal activity and significantly reduced mold symptoms in grapes. Moreover, all tested natural extracts were able to reduce OTA content in grape berries (17.7 ± 8.3 % - 82.3 ± 3.85 % inhibition), although not always significantly. Eucalyptus extract was particularly efficient, inhibiting OTA production by both strains of A. carbonarius by up to >80 % with no effects on fungal growth. The use of natural eucalyptus extract represents a feasible strategy to reduce OTA formation without disrupting fungal growth, apparently maintaining the natural microbial balance, while cistus and orange peel extracts appear promising as inhibitors of A. carbonarius mycelial growth. Our findings suggest that plant extracts may be useful sources of bioactive chemicals for preventing A. carbonarius contamination and OTA production. Nonetheless, it will be necessary to evaluate their effect on the organoleptic properties of the grapes.
Asunto(s)
Ocratoxinas , Vitis , Vitis/microbiología , Antifúngicos/farmacología , Extractos Vegetales/farmacología , AspergillusRESUMEN
The jujube is one of the most popular fruits in China because of its delicious taste and high nutritional value. It has a long history of usage as an important food or traditional medicine. However, the jujube is easily infected by fungi, which causes economic losses and threatens human health. When the jujube was infected by Aspergillus niger (H1), the changes in nutritional qualities were determined, such as the content of total acid, vitamin C, reducing sugar, etc. In addition, the ability of A. niger (H1) to produce ochratoxin A (OTA) in different inoculation times and culture media was evaluated, and the content of OTA in jujubes was also analyzed. After jujubes were infected by A. niger (H1), the total acid, and vitamin C contents increased, while the total phenol content decreased, and the reducing sugar content increased after an initial decrease. Although A. niger (H1) infection caused the jujubes to rot and affected its quality, OTA had not been detected. This research provides a theoretical foundation for maximizing edible safety and evaluating the losses caused by fungal disease in jujubes.
Asunto(s)
Ocratoxinas , Ziziphus , Humanos , Frutas/química , Ocratoxinas/análisis , Aspergillus niger , Ácido Ascórbico , Azúcares , Contaminación de Alimentos/análisisRESUMEN
The Gram-positive bacteria lactic acid bacteria (LAB) are used in the food industry but are also known for inhibiting certain food spoilage microorganisms, especially fungi. Sources of nitrogen (N) for culture media are generally organic and expensive. Many attempts have been made to formulate economical culture media with alternative N sources obtained from agricultural and industrial byproducts. This study describes the design and optimization of an inexpensive culture medium for Lactiplantibacillus plantarum (formerly Lactobacillus plantarum) MZ809351 strain B31. The culture medium was optimized using statistical experimental designs to identify the factors with the most significant effects on biomass concentration to reduce the overall cost, aiming to obtain a biomass concentration similar to that obtained with the reference LAB culture medium (de Man, Rogosa and Sharpe; MRS). Sodium acetate and magnesium sulfate were the most significant factors (p < 0.005), and their contents were reduced by 22 % and 40 %, respectively, without affecting biomass concentration. Malt germ extract (MGE) was used as an alternative nitrogen source to replace meat extract (ME) and proteose peptone (PP). Through these experiments, the composition of a culture medium that is less expensive than MRS broth was defined, which produced a biomass concentration (3.8 g/L) similar to that obtained with MRS medium. The inhibitory effects of two LAB strains isolated from the Ivory Coast and Mexico on the growth and production of ochratoxin A (OTA) in an ochratoxigenic fungus was tested. The minimum cellular concentration of the LAB to prevent the development of Aspergillus carbonarius Ac 089 and the production of OTA was determined in a model assay in Petri dishes. The conditions to inhibit the germination of A. carbonarius Ac 089 and the production of OTA were found. Using the optimized medium and a ratio of 2 × 104 LAB/spore (1 × 108 CFU/mL) strain B7 (L. plantarum MZ809351) and 2 × 103 LAB/spore (1 × 107 CFU/mL) strain B31 (L. plantarum MN922335) completely inhibited the growth of the fungus. A ratio of 2 × 105 LAB/spore (1 × 109 CFU/mL) was required to inhibit OTA production with strains B7 and B31. This study indicates the potential of cultivating LAB in an optimized and inexpensive culture medium for use as a biological control agent against ochratoxigenic fungi in food.
Asunto(s)
Lactobacillales , Ocratoxinas , Humanos , Medios de Cultivo , Nitrógeno/farmacología , Extractos VegetalesRESUMEN
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.
Asunto(s)
Aptámeros de Nucleótidos , Técnicas Biosensibles , Micotoxinas , Nanosferas , Ocratoxinas , Passiflora , Puntos Cuánticos , Humanos , Dióxido de Silicio , Harina , Triticum , Ocratoxinas/análisis , Límite de DetecciónRESUMEN
Ochratoxin A (OTA) is considered one of the main mycotoxins responsible for health problems and considerable economic losses in the feed industry. The aim was to study OTA's detoxifying potential of commercial protease enzymes: (i) Ananas comosus bromelain cysteine-protease, (ii) bovine trypsin serine-protease and (iii) Bacillus subtilis neutral metalloendopeptidase. In silico studies were performed with reference ligands and T-2 toxin as control, and in vitro experiments. In silico study results showed that tested toxins interacted near the catalytic triad, similar to how the reference ligands behave in all tested proteases. Likewise, based on the proximity of the amino acids in the most stable poses, the chemical reaction mechanisms for the transformation of OTA were proposed. In vitro experiments showed that while bromelain reduced OTA's concentration in 7.64% at pH 4.6; trypsin at 10.69% and the neutral metalloendopeptidase in 8.2%, 14.44%, 45.26% at pH 4.6, 5 and 7, respectively (p < 0.05). The less harmful α-ochratoxin was confirmed with trypsin and the metalloendopeptidase. This study is the first attempt to demonstrate that: (i) bromelain and trypsin can hydrolyse OTA in acidic pH conditions with low efficiency and (ii) the metalloendopeptidase was an effective OTA bio-detoxifier. This study confirmed α-ochratoxin as a final product of the enzymatic reactions in real-time practical information on OTA degradation rate, since in vitro experiments simulated the time that food spends in poultry intestines, as well as their natural pH and temperature conditions.
Asunto(s)
Micotoxinas , Ocratoxinas , Animales , Bovinos , Ocratoxinas/análisis , Bromelaínas , Simulación del Acoplamiento Molecular , Tripsina , Alimentación Animal/análisis , MetaloendopeptidasasRESUMEN
Ochratoxin (OT) contamination of medicinal herbs is a serious threat to human health. This study was performed to investigate the mechanism of OT contamination of licorice (Glycyrrhiza sp.) root. Licorice root samples were cut into eight parts, which were placed separately on sucrose-free Czapek Dox agar medium, inoculated with the spores of ochratoxigenic Aspergillus westerdijkiae. After incubation for 10 and 20 days, the OT contents of the samples were determined by high-performance liquid chromatography, and microtome sections prepared from the samples were analyzed by desorption electrospray ionization tandem mass spectrometry, to visualize OT localization. The same sections were further examined by light microscopy and scanning electron microscopy, to investigate the path of fungal mycelial penetration of the inner roots. OT concentrations tended to increase from the upper- to the middle-root parts. OTs were located in cut areas and areas of cork layer damage; they were not present in the undamaged cork layer, indicating that the structure of this layer prevents OT contamination of the licorice root.
Asunto(s)
Glycyrrhiza , Ocratoxinas , Humanos , Ocratoxinas/análisis , Cromatografía Líquida de Alta Presión/métodos , Antioxidantes/análisis , Espectrometría de Masa por Ionización de Electrospray , Glycyrrhiza/química , Raíces de Plantas/químicaRESUMEN
In this work, a fast mycotoxin extraction (FaMEx) technique was developed for the rapid identification and quantification of carcinogenic ochratoxin-A (OTA) in food (coffee and tea) and agricultural soil samples using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) detection. The FaMEx technique advancement is based on two plastic syringes integrated setup for rapid extraction and its subsequent controlled clean-up process. In the extraction process, a 0.25-g sample and extraction solvent were added to the first syringe barrel for the vortex-based extraction. Then, the extraction syringe was connected to a clean-up syringe (pre-packed with C18, activated carbon, and MgSO4) with a syringe filter. Afterward, the whole set-up was placed in an automated programmable mechanical set-up for controlled elution. To enhance FaMEx technology performance, the various influencing sample pretreatment parameters were optimized. Furthermore, the developed FaMEx method indicated excellent linearity (0.9998 and 0.9996 for coffee/tea and soil) with highly sensitive detection (0.30 and 0.29 ng/mL for coffee/tea and soil) and quantification limits (1.0 and 0.96 for coffee/tea and soil), which is lower than the toxicity limit compliant with the European Union regulation for OTA (5 ng/g). The method showed acceptable relative recovery (84.48 to 100.59%) with <7.34% of relative standard deviation for evaluated real samples, and the matrix effects were calculated as <-13.77% for coffee/tea and -9.7 for soil samples. The obtained results revealed that the developed semi-automated FaMEx/UHPLC-MS/MS technique is easy, fast, low-cost, sensitive, and precise for mycotoxin detection in food and environmental samples.
Asunto(s)
Micotoxinas , Ocratoxinas , Cromatografía Líquida de Alta Presión/métodos , Micotoxinas/análisis , Ocratoxinas/análisis , Espectrometría de Masas en Tándem/métodos , Café/química , Jeringas , Suelo , Té/químicaRESUMEN
ABSTRACTSTea (Camellia sinensis L.) is a high valued beverage worldwide since ancient times; more than three billion cups of tea are consumed each day. Leaf extracts of the plant are used for food preservation, cosmetics, and medicinal purposes. Nevertheless, tea contaminated with mycotoxins poses a serious health threat to humans. Mycotoxin production by tea fungi is induced by a variety of factors, including poor processing methods and environmental factors such as high temperature and humidity. This review summarizes the studies published to date on mycotoxin prevalence, toxicity, the effects of climate change on mycotoxin production, and the methods used to detect and decontaminate tea mycotoxins. While many investigations in this domain have been carried out on the prevalence of aflatoxins and ochratoxins in black, green, pu-erh, and herbal teas, much less information is available on zearalenone, fumonisins, and Alternaria toxins. Mycotoxins in teas were detected using several methods; the most commonly used being the High-Performance Liquid Chromatography (HPLC) with fluorescence detection, followed by HPLC with tandem mass spectrometry, gas chromatography and enzyme-linked immunosorbent assay. Further, mycotoxins decontamination methods for teas included physical, chemical, and biological methods, with physical methods being most prevalent. Finally, research gaps and future directions have also been discussed.
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Camellia sinensis , Micotoxinas , Ocratoxinas , Humanos , Micotoxinas/análisis , Té/química , Bebidas/análisis , Hongos , Camellia sinensis/química , Cromatografía Líquida de Alta PresiónRESUMEN
Ochratoxin A (OTA) is a common mycotoxin with high carcinogenicity; therefore, it is crucial to establish a simple, rapid, and sensitive method for its detection. In this study, we developed a "turn-on" fluorescence assay for detecting OTA based on guanine quenching of the aptamer. The method uses fluorescein (FAM) fluorophore to label the complementary strand of the OTA aptamer, Fc-DNA. In the absence of OTA, the Fc-DNA hybridizes with the aptamer to form a double strand. Due to the occurrence of photo-induced electron transfer (PET), the FAM fluorescence signal is quenched as the FAM on the Fc-DNA approaches the guanine of the aptamer at the 5' end. When OTA is present, the aptamer binds to it and thus, is unable to hybridize with Fc-DNA to form a double strand; the FAM fluorescence signal is restored as FAM moves away from the guanine of the aptamer. The assay achieved OTA detection at a detection limit of 28.4 nM. The application of the original guanine of the aptamer as the quenching agent helps avoid the complex designing and labeling of the aptamer, which ensures the high affinity of the aptamer for OTA. Meanwhile, this "turn-on" detection mode helps avoid potential false-positive results as in the "turn-off" mode and improves the assay's sensitivity. Additionally, the method has good selectivity and can be used to detect OTA in traditional Chinese medicine. This method provides a simple, low-cost, and rapid method for OTA detection.
Asunto(s)
Aptámeros de Nucleótidos , Técnicas Biosensibles , Ocratoxinas , Límite de Detección , Aptámeros de Nucleótidos/metabolismo , Ocratoxinas/análisis , Colorantes Fluorescentes , Técnicas Biosensibles/métodosRESUMEN
On-site screening of biotoxins is of great importance for food safety. A new electrochemical-biosensing strategy was constructed for ochratoxin A (OTA) detection by direct using ready-made commercial portable-glucose-meter (PGM). Aptamer against OTA was adopted as the recognition probe and pre-immobilized onto the sensing interface. The complementary biotin-modified probe was further decorated by hybridization. Biotinylated invertase was further introduced onto the sensing system with streptavidin, which also acted as the signal amplification unit. The invertase, which was depended on the amount of OTA, produced the glucose from sucrose in the sensing solution. The glucose could be directly and conveniently measured with PGM. Quantitative analysis of OTA was achieved with a linear range from 0.5 ng/mL to 10 ng/mL and detection limit of 0.45 ng/mL. Of significance, it has been successfully applied for OTA analysis in rice with satisfied recoveries. This unique PGM-based electrochemical platform reveals prospective potential in food safety monitoring.