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1.
J Agric Food Chem ; 68(7): 2193-2200, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-31976658

RESUMO

Various mycotoxins widely co-exist in agro-products, and their combined effects cause toxicity and potential carcinogenicity to humans and animals. In this work, we developed an economical and sensitive quantum dots (QDs)/QD microbead (QDs/QB)-based multiplex immunochromatographic assay (mICA) for the rapid detection of fumonisin B1 (FB1), zearalenone (ZEN), and ochratoxin A (OTA) without the building-up process of mycotoxin conjugates. QDs and QBs were selected as fluorescent reporters and conjugated with antimycotoxin monoclonal antibodies for improving sensitivity. Furthermore, phage-displayed FB1, ZEN, and OTA mimotope peptide-based soluble and monovalent fusions to maltose-binding protein (MBP) were applied onto the test line of the mICA as the mimetic coating antigen. Under the optimized conditions, the visual detection limits (vLODs) of peptide-MBP-based mICA could be obtained as 0.25 ng/mL for FB1, 3.0 ng/mL for ZEN, and 0.5 ng/mL for OTA within 10 min. The results for spiked real sample detection indicate good accuracy, reproducibility, and practicability. In addition, the proposed mICA was comparable with ultraperformance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) in terms of reliability in detecting FB1, ZEN, and OTA using natural samples. From the point of promoting commercial production, these time-saving and low-cost peptide-MBP antigens applied in ICA might provide promising potential for promoting productivity and decreasing the cost of production.


Assuntos
Fumonisinas/análise , Imunoensaio/métodos , Ocratoxinas/análise , Zearalenona/análise , Contaminação de Alimentos/análise , Imunoensaio/economia , Imunoensaio/instrumentação , Limite de Detecção , Proteínas Ligantes de Maltose/química , Pontos Quânticos/química
2.
J Agric Food Chem ; 68(7): 2249-2255, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-31986034

RESUMO

Ochratoxin A (OTA) is an intrinsically fluorescent phenolic mycotoxin that contaminates a wide range of food products and is a serious health threat to animals and humans. An OTA binding aptamer (OTABA) that folds into an antiparallel G-quadruplex (GQ) in the absence and presence of target OTA has been incorporated into a vast variety of aptasensor platforms for OTA detection. The development of a simple, aptamer-based approach would allow for detection of the toxin without the use of complex analytical instrumentation, which has been the gold standard for OTA detection thus far. However, to date, none of the aptasensor platforms have utilized the natural fluorescence of the phenolic toxin for detection. Herein, we report that OTA binding to OTABA involves π-stacking interactions that lead to GQ-to-toxin energy transfer (ET), which affords a "turn-on" fluorescence self-signaling platform in which the emission of the aptamer-target complex is enhanced in comparison to the free toxin alone. Selective excitation of the GQ-OTA complex at 256 nm leads to a 4-fold enhancement in OTA fluorescence. The GQ-OTA ET detection platform boasts a limit of detection ∼2 ng/mL, which is comparable to a previously demonstrated fluorescence resonance energy transfer immunoassay platform for OTA detection, and displays excellent OTA selectivity and recovery from red wine samples.


Assuntos
Aptâmeros de Nucleotídeos/química , Transferência Ressonante de Energia de Fluorescência/métodos , Ocratoxinas/análise , Vinho/análise , Transferência Ressonante de Energia de Fluorescência/instrumentação , Contaminação de Alimentos/análise , Limite de Detecção
3.
Anal Bioanal Chem ; 412(1): 81-91, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31953713

RESUMO

Methods for detecting mycotoxins are very important because of the great health hazards of mycotoxins. However, there is a high background and low signal-to-noise ratio in real-time sensing, and therefore it is difficult to meet the fast, accurate, and convenient requirements for control of food quality. Here we constructed a quantitative fluorescence image analysis based on multicolor upconversion nanocrystal (UCN)-encoded microspheres for detection of ochratoxin A and zearalenone. The background-free encoding image signal of UCN-doped microspheres was captured by fluorescence microscopy under near-infrared excitation, whereas the detection image signal of phycoerythrin-labeled secondary antibodies conjugated to the microspheres was captured under blue light excitation. We custom-wrote an algorithm to analyze the two images for the same sample in 10 s, and only the gray value in the red channel of the secondary probe confirmed the quantity. The results showed that this novel detection platform performed feasible and reliable fluorescence image measurements by this method. Additionally, the limit of detection of was 0.34721 ng/mL for ochratoxin A and 0.41162 ng/mL for zearalenone. We envision that this UCN encoding strategy will be usefully applied for fast, accurate, and convenient testing of multiple food contaminants to ensure the safety of the food.


Assuntos
Microesferas , Ocratoxinas/análise , Zearalenona/análise , Contaminação de Alimentos/análise , Imunoensaio/métodos , Limite de Detecção , Nanopartículas/química , Razão Sinal-Ruído
4.
J Sci Food Agric ; 100(3): 1118-1123, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31667844

RESUMO

BACKGROUND: Dairy farming feed can be contaminated with mycotoxins, affecting animals' health and milk quality. Dairy farming is also prone to occupational exposure to mycotoxins, and feed is recognized as a source of contamination in the workplace. An exploratory study was developed in a dairy farm located in Portugal intending to assess the mycotoxins present in the feed. RESULTS: All the samples analyzed presented contamination by at least two mycotoxins and up to a maximum of 13 mycotoxins in the same sample. Zearalenone (ZEA) was detected in all the samples (n = 10) followed by deoxynivalenol (DON), which was reported in eight samples, and ochratoxin A (OTA), reported in five samples. CONCLUSION: The results point to the possible contamination of milk by several mycotoxins and raise the possibility of occupational exposure to mycotoxins due to feed contamination. An adequate One Health approach for dairy production should address these issues through effective preventive actions such as avoiding the use of feed contaminated with mycotoxins. This represents an important challenge due to climate change. It requires proper attention and accurate management measures. © 2019 Society of Chemical Industry.


Assuntos
Doenças dos Trabalhadores Agrícolas/etiologia , Ração Animal/análise , Leite/química , Micotoxinas/análise , Exposição Ocupacional/efeitos adversos , Doenças dos Trabalhadores Agrícolas/prevenção & controle , Animais , Bovinos , Fazendeiros/estatística & dados numéricos , Fazendas , Contaminação de Alimentos/análise , Humanos , Micotoxinas/toxicidade , Exposição Ocupacional/análise , Exposição Ocupacional/prevenção & controle , Ocratoxinas/análise , Ocratoxinas/toxicidade , Portugal , Zearalenona/análise , Zearalenona/toxicidade
5.
J Agric Food Chem ; 68(1): 369-375, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31829586

RESUMO

A sensitive fluorescent DNA hydrogel aptasensor based on the self-assembly of rolling circle amplification (RCA) products was developed for ochratoxin A (OTA) detection in beer. A competitive binding mode of aptamer, complementary sequence, and target was integrated into the DNA hydrogel for OTA detection. The OTA aptamer first combined with the primer to form the hybridized product. Then, in the presence of OTA, the aptamer combined with OTA, which released the primer. The released primer hybridized with the padlock probe to form a circular template, and the RCA reaction was initiated by adding ligase, polymerase, and dNTPs. The fluorescent DNA hydrogel was obtained by adding Cy3-dUTP together with dNTPs, and the fluorescence (FL) intensity of the DNA hydrogel was positively correlated with OTA concentration. Under the optimal experimental conditions, the linear range of the relationship varied from 0.05 ng/mL to 100 ng/mL with a detection limit for OTA of 0.01 ng/mL. The fluorescent DNA hydrogel aptasensor showed good specificity and stability in beer samples. Therefore, the fabricated DNA hydrogel aptasensor shows considerable potential applications in detecting OTA for food safety.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , DNA/química , Hidrogéis/química , Técnicas de Amplificação de Ácido Nucleico/métodos , Ocratoxinas/análise , Aptâmeros de Nucleotídeos/genética , Cerveja/análise , Técnicas Biossensoriais/instrumentação , DNA/genética , Fluorescência , Contaminação de Alimentos/análise , Limite de Detecção , Técnicas de Amplificação de Ácido Nucleico/instrumentação
6.
Food Chem ; 305: 125429, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31505415

RESUMO

A simple and rapid magnetic solid-phase extraction (MSPE) method using PEGylated multi-walled carbon nanotubes magnetic nanoparticles (PEG-MWCNTs-MNP) as absorbents is proposed for isolation and enrichment of aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1), aflatoxin G2 (AFG2), aflatoxin M1 (AFM1), aflatoxin M2 (AFM2), ochratoxin A (OTA), zearalenone (ZEA), zearalanone (ZAN), α-zeralanol (α-ZAL), ß-zeralanol (ß-ZAL), α-zeralenol (α-ZOL), and ß-zeralenol (ß-ZOL) from liquid milk. Combined with ultra-high performance liquid chromatography Q-Exactive high resolution mass spectrometry, simultaneous qualification of these mycotoxins was achieved with sensitivity and specificity. The proposed method showed a good linearity (R2 ≥ 0.995), high sensitivity (limit of detection in the range of 0.005-0.050 µg/kg and limit of quantification in the range of 0.015-0.150 µg/kg), adequate recovery (81.8-106.4%), and good repeatability (intra-day precision in the range of 2.1-8.5% and inter-day precision in the range of 3.9-11.7%). It has been successfully applied to the determination of 13 mycotoxins in real liquid milk samples.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Leite/química , Micotoxinas/análise , Extração em Fase Sólida/métodos , Aflatoxinas/análise , Animais , Magnetismo , Nanotubos de Carbono , Ocratoxinas/análise , Sensibilidade e Especificidade , Zearalenona/análise
7.
Anal Chim Acta ; 1087: 113-120, 2019 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-31585559

RESUMO

A highly sensitive fluorescence turn-off biosensor for the detection of ochratoxin A (OTA) was developed based on graphene oxide (GO) and an aptamer-induced detachable nanoladders. In this assay, two types of ssDNA (H1 and H2) were involved in the assembly of the DNA nanoladders, in which H1 was labeled with fluorophore, and H2 was the OTA binding aptamer. Self-assembly of the DNA nanoladders with the addition of GO weakened its adsorption and the fluorescence intensity remained strong. In the presence of OTA, the aptamer was specifically recognized and an aptamer-OTA complex was formed, leading to the detached of DNA nanoladders. With the addition of GO, the released H1 was adsorbed on the GO surface, thus efficiently quenching the fluorescence signal (turning off). The detection limit of OTA in this assay was 4.59 nM. To improve the sensitivity of this strategy, we creatively developed an alternative strategy to replace the sturdy nanoladders with frail nanoladders. More precisely, the sequences of H1 had mismatched bases, which, when hybridized with H2 could be used to create long non-perfect complementary nanoladders. For the mismatched bases-based frail nanoladders, it was easier for OTA to bind its aptamer sequence, thus enabling a more thorough and faster detachment of the nanoladders, along with a greater degree of fluorescence quenching. The detection limit for OTA was estimated to be 0.1 nM. The biosensors we developed were sensitive, specific, enzyme-free, cost-effective and can be applied in red wine samples spiked with known concentration of OTA.


Assuntos
Aptâmeros de Nucleotídeos/química , DNA de Cadeia Simples/química , Contaminação de Alimentos/análise , Grafite/química , Nanoestruturas/química , Ocratoxinas/análise , Técnicas Biossensoriais/métodos , DNA de Cadeia Simples/genética , Corantes Fluorescentes/química , Limite de Detecção , Hibridização de Ácido Nucleico , Espectrometria de Fluorescência/métodos , Vinho/análise
8.
Wei Sheng Yan Jiu ; 48(4): 646-650, 2019 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-31601350

RESUMO

OBJECTIVE: To establish a method for determination of ochratoxin A and ochratoxin alpha in wine by ultra-performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS) based on isotopic internal standard method. METHODS: The wine sample was adjusted to pH 9. 0 by 5% ammonia and concentrated by a MAX solid phase extraction cartridge. The UPLC separation was performed on a ACQUITY BEH C_(18) column(100 mm×2. 1 mm, 1. 7 µm)with a isocratic elution program of acetonitrile and 5 mmol/L ammonium acetate as the mobile phase. Electrospray ionization was applied and operated in the positive ion mode. The concentration of wine was quantified by isotope internal standard. RESULTS: The calibration curves were linear in the concentration range of 1. 0-50. 0 µg/L, the coefficients of correlation were 0. 9996 and 0. 9993, respectively. The limits of detection(LODs) of both were 0. 10 µg/kg, and the limits of quantitative were 0. 35 µg/kg. The average recoveries at the spiked levels of 0. 35, 2. 00 and 10. 00 mg/kg were 88. 6%-108. 0%, and the relative standard deviations(RSDs) were 2. 1%-9. 2%, respectively. CONCLUSION: This method is simple, sensitive, accurate and reliable, which is suitable for the determination of ochratoxin A and ochratoxin alpha in wine.


Assuntos
Ocratoxinas/análise , Espectrometria de Massas em Tandem , Vinho/análise , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida
9.
Ecotoxicol Environ Saf ; 184: 109637, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31499447

RESUMO

OTA is a toxic metabolite produced by fungus belonging to Aspergillus and Penicillium genera. Kidney is the main target of this toxin; OTA is considered as one of the etiological factors at the origin of the human Balkan endemic nephropathy. microRNA are short non-coding transcrips (18-22 nucleotides in length) regulating key cellular processes. Various miRNAs have been established to play important roles in development of renal carcinoma and urothelial cancer. The objective of this study is to analyse the miRNA profiling in the kidney of piglets experimentally intoxicated with feed contaminated with OTA. Fifteen piglets (five pigs/group) were randomly distributed into 3 groups, fed normal diet (Group 1: control), or diets contaminated with OTA in two concentrations: 50 µg OTA/kg feed (Group 2: 50 µg OTA/kg feed) or 200 µg OTA/kg feed (Group 3: 200 µg OTA/kg feed) for 28 days. At the end of the experiment blood samples were taken for serological analyses. Animals from control group and 200 µg OTA/kg feed were sacrificed and kidney samples were taken for histological and molecular analyses. As resulted from molecular profiling study there are 8 miRNA differentially expressed in OTA kidney vs control kidney, in which five miRNA were overexpressed in the kidney of OTA intoxicated animals: miR-497 (FC = 6.34), miR-133a-3p (FC = 5.75), miR-423-3p (FC = 5.48), miR-34a (FC = 1.68), miR-542-3p (1.65) while three miRNA were downregulated: miR-421-3p (FC = -3.96); miR-490 (FC = -3.87); miR-9840-3p (FC = -2.13). The altered miRNAs as effect of OTA are strongly connected to the engine of cancer, disturbing nodal points in different pathways, as TP53 signalling. This proof-of-concept study proves the actual utility of miRNAs as biomarkers of mycotoxin exposure, including OTA.


Assuntos
Rim/efeitos dos fármacos , MicroRNAs/genética , Ocratoxinas/toxicidade , Suínos , Transcriptoma/efeitos dos fármacos , Ração Animal/análise , Animais , Biomarcadores/sangue , Contaminação de Alimentos/análise , Humanos , Rim/metabolismo , Rim/patologia , Masculino , MicroRNAs/metabolismo , Modelos Teóricos , Ocratoxinas/análise , Distribuição Aleatória
10.
Analyst ; 144(19): 5866-5874, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31482879

RESUMO

To enhance the sensitivity of an aptasensor, a novel strategy was designed to develop an electrochemical aptasensor based on poly(3,4-ethylenedioxy thiophene)-gold nanoflower (PEDOT-AuNF) composites supported on a three-dimensional graphene oxide sponge (GOS). GOS with a three-dimensional sponge-like porous structure, exhibiting excellent electrical conductivity and a large surface area, provided the first amplification of the electrochemical signal for ochratoxin A (OTA) detection. PEDOT-AuNFs, synthesized by an ionic liquid-assisted one-pot method, presented a peculiar hierarchical flower-like structure, a high electroactive surface area, and more binding sites for immobilizing the aptamer molecules by the Au-S bonds. When PEDOT-AuNFs were supported on the surface of GOS by the interaction of the π-π packing between PEDOT and graphene oxide, a synergistic effect was produced to provide the second amplification for the aptasensor. PEDOT-AuNFs/GOS provided an ultrasensitive detection technique by multiple signal amplification for the electrochemical sensing of OTA. Consequently, this strategy not only endowed the aptasensor with high sensitivity but also needed no complicated signal amplification. The electrochemical sensor was fabricated successfully on a glassy carbon electrode to detect OTA with a linear response in the range of 0.01-20 ng L-1 and a limit of detection of 4.9 pg L-1. Moreover, it displayed good specificity, reproducibility and stability. The utilization of the proposed aptasensor for the quantitative determination of OTA in wine indicates that it can find promising applications in detecting OTA and even other mycotoxins in foodstuffs.


Assuntos
Aptâmeros de Nucleotídeos/química , Compostos Bicíclicos Heterocíclicos com Pontes/química , Grafite/química , Nanopartículas Metálicas/química , Ocratoxinas/análise , Polímeros/química , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Contaminação de Alimentos/análise , Ouro/química , Limite de Detecção , Reprodutibilidade dos Testes , Vinho/análise
11.
Anal Bioanal Chem ; 411(29): 7717-7724, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31392435

RESUMO

This work reports on further development of an optical biosensor for the in vitro detection of mycotoxins (in particular, aflatoxin B1) using a highly sensitive planar waveguide transducer in combination with a highly specific aptamer bioreceptor. This sensor is built on a SiO2-Si3N4-SiO2 optical planar waveguide (OPW) operating as a polarization interferometer (PI), which detects a phase shift between p- and s-components of polarized light propagating through the waveguide caused by the molecular adsorption. The refractive index sensitivity (RIS) of the recently upgraded PI experimental setup has been improved and reached values of around 9600 rad per refractive index unity (RIU), the highest RIS values reported, which enables the detection of low molecular weight analytes such as mycotoxins in very low concentrations. The biosensing tests yielded remarkable results for the detection of aflatoxin B1 in a wide range of concentrations from 1 pg/mL to 1 µg/mL in direct assay with specific DNA-based aptamers. Graphical abstract Optical planar waveguide polarization interferometry biosensor for detection of aflatoxin B1 using specific aptamer.


Assuntos
Aflatoxina B1/análise , Aptâmeros de Nucleotídeos/química , Interferometria/métodos , Técnicas Biossensoriais , Técnicas In Vitro , Limite de Detecção , Ocratoxinas/análise , Óptica e Fotônica , Refratometria , Dióxido de Silício/química
12.
Food Chem Toxicol ; 133: 110756, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31408721

RESUMO

Yeasts are able to reduce the levels of ochratoxin A in fermentative processes; and, through their enzymatic complex, these micro-organisms are also capable of forming modified mycotoxins. These mycotoxins are often underreported, and may increase health risks after ingestion of contaminated food. In this sense, this study aims to evaluate whether the presence of ochratoxin A influences yeast growth kinetic parameters and to elucidate the formation of modified ochratoxin by Saccharomyces cerevisiae strains during fermentation. Three S. cerevisiae strains (12 M, 01 PP, 41 PP) were exposed to OTA at the concentrations of 10, 20 and 30 µg/L. The Baranyi model was fitted to the growth data (Log CFU/mL), and the identification of modified ochratoxins was performed through High Resolution Mass Spectrometry. The presence of ochratoxin A did not influence the growth of S. cerevisiae strains. Four pathways were proposed for the metabolization of OTA: dechlorination, hydrolysis, hydroxylation, and conjugation. Among the elected targets, the following were identified: ochratoxin α, ochratoxin ß, ochratoxin α methyl ester, ochratoxin B methyl ester, ethylamide ochratoxin A, ochratoxin C, hydroxy-ochratoxin A, hydroxy-ochratoxin A methyl ester, and ochratoxin A cellobiose ester. These derivatives formed from yeast metabolism may contribute to the occurrence of underreporting levels of total mycotoxin in fermented products.


Assuntos
Ocratoxinas/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/crescimento & desenvolvimento , Biotransformação , Sobrevivência Celular/efeitos dos fármacos , Cinética , Modelos Biológicos , Ocratoxinas/análise
13.
Food Microbiol ; 84: 103253, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31421787

RESUMO

Fifteen samples of semi-hard ripened cheeses, both spoiled (10) and unspoiled (5), and obtained from cheese factories located in Northwest of Spain, were analysed by a dilution plating technique and direct sampling. A total of 32 isolates were identified at species level by a polyphasic approach (phenotypic characterization, partial extrolite analysis and molecular identification). Most isolates (65.6%) belonged to the species P. commune; other species found were P. solitum, P. chrysogenum, P. nordicum, P. expansum and P. cvjetkovicii. All of the P. commune isolates were able to produce cyclopiazonic acid, while the P. nordicum and the P. expansum isolates were producers of ochratoxin A and patulin respectively. Despite this, the role of P. commune as beneficial fungi in cheese ripening should be investigated. Molecular identification based on BenA sequence analysis was able to identify the majority of isolates. The three mycotoxins investigated can be considered key for identification. The polyphasic approach seems to be a very valuable tool for identification of isolates of this complex genus.


Assuntos
Queijo/microbiologia , Microbiologia de Alimentos/métodos , Penicillium/isolamento & purificação , Proteínas Fúngicas/genética , Indóis/análise , Ocratoxinas/análise , Patulina/análise , Penicillium/classificação , Fenótipo , Espanha
14.
J Chromatogr A ; 1604: 460475, 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31466701

RESUMO

Enrichment, separation and purification are very important to accurately analyze mycotoxins in complicated samples. In the work, we developed a new enrichment, purification and high-performance liquid chromatography combined with fluorescence detector (HPLC-FLD) for aflatoxins B1 (AFB1), ochratoxin A (OTA) and Zearalenone (ZEN) assay using the macroporous magnetic 3D photonic crystal microspheres (3DPCMs). The conditions of enrichment and purification for mycotoxins have been optimized, which are as follows: pore size of 3DPCMs at 280 nm, 1:1 methanol:acetonitrile (v/v) as eluent, antibody concentrations at 60 µg/mL,60 µg/mL and 120 µg/mL for OTA, AFB1 and ZEN, respectively. The recovery rates in the rice, wheat and corn samples range from 70.01% to 100.12% and the relative standard deviation (RSD) range from 0.45% to 7.09%. The recovery rates used 3DPCMs are almost tenfold higher than that used non-macroporous PCMs in the same conditions. The developed method is simple, rapid (time including enrichment, purification and detection <2 h) and only requires small volume reagents (≤200 µL).


Assuntos
Cromatografia Líquida de Alta Pressão/instrumentação , Cromatografia Líquida de Alta Pressão/métodos , Microesferas , Micotoxinas/análise , Fótons , Aflatoxina B1/análise , Aflatoxina B1/isolamento & purificação , Anticorpos/química , Cristalização , Fluorescência , Proteínas Imobilizadas/química , Micotoxinas/isolamento & purificação , Ocratoxinas/análise , Ocratoxinas/isolamento & purificação , Porosidade , Propriedades de Superfície , Zearalenona/análise , Zearalenona/isolamento & purificação
15.
Molecules ; 24(15)2019 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-31382421

RESUMO

A rapid and reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for simultaneous determination of ochratoxin A (OTA) and its metabolite ochratoxin α (OTα), for the first time, in dairy cow plasma, milk, urine, heart, liver, spleen, lung, and kidney. The established method was extensively validated by determining the linearity (R2 ≥ 0.990), sensitivity (lower limit of quantification, 0.1-0.2 ng mL-1), recovery (75.3-114.1%), precision (RSD ≤ 13.6%), and stability (≥83.0%). Based on the methodological advances, the carry-over of OTA was subsequently studied after oral administration of 30 µg/kg body weight OTA to dairy cows. As revealed, OTA and OTα were detected in urine, with maximal concentrations of 1.8 ng mL-1 and 324.6 ng mL-1, respectively, but not in milk, plasma, or different tissues, verifying the protection effects of rumen flora against OTA exposure for dairy cows. Moreover, 100 fresh milk samples randomly collected from different supermarkets in Shanghai were also analyzed, and no positive samples were found, further proving the correctness of the in vivo biotransformation results. Thus, from the currently available data, regarding OTA contamination issues on dairy cows, no significant health risks were related to OTA exposure due to the consumption of these products.


Assuntos
Cromatografia Líquida , Contaminação de Alimentos/análise , Ocratoxinas/análise , Ocratoxinas/química , Espectrometria de Massas em Tandem , Animais , Líquidos Corporais/química , Bovinos , Cromatografia Líquida/métodos , Leite/química , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem/métodos
16.
J Agric Food Chem ; 67(32): 9022-9031, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31339724

RESUMO

The quantitative multiplex immunochromatographic assay (mICA) has received an increasing amount of attention in multitarget detection. However, the quantitative results in the reported mICAs were obtained by recording the signals on the test lines that with which various analyte-independent factors readily interfere, resulting in inaccurate quantitation. The ratiometric strategy using the T/C value (ratios of signals on the test line to those of the control line) for signal correction can effectively circumvent these issues to enable more accurate detection. Herein, we present for the first time a novel ratiometric mICA strip with multiple T lines for the simultaneous quantitative detection of aflatoxin B1 (AFB1), fumonisin B1 (FB1), and ochratoxin A (OTA) using highly luminescent quantum dot nanobeads (QBs) as enhanced signal reporters. To achieve reliable ratiometric signal output, a biotin-streptavidin system was introduced to replace the conventional anti-mouse IgG antibody for reliable reference signals on the control line that are completely independent of the signal probe and analyte. By using stable T/C values as quantitative signals, our proposed QB-mICA method can successfully detect three mycotoxins with concentrations as low as 1.65 pg/mL for AFB1, 1.58 ng/mL for FB1, and 0.059 ng/mL for OTA. The detection performance of the developed QB-mICA strip, including precision, specificity, and reliability, was further evaluated using artificially contaminated cereal samples. The results demonstrate the improved accuracy and reliability of quantitative determination by comparison with the anti-mouse IgG antibody. Thus, this work provides a promising strategy for developing a ratiometric mICA method for accurately quantifying multiple analytes using the biotin-SA system, opening up a new direction in quantitative mICAs.


Assuntos
Aflatoxina B1/análise , Fumonisinas/análise , Imunoensaio/métodos , Ocratoxinas/análise , Animais , Biotina/química , Grão Comestível/química , Contaminação de Alimentos/análise , Imunoensaio/instrumentação , Luminescência , Camundongos , Micotoxinas , Pontos Quânticos , Estreptavidina/química
17.
Artigo em Inglês | MEDLINE | ID: mdl-31302476

RESUMO

In this study, a simple, efficient and rapid Ultra High Performance Liquid Chromatography method with fluorescence detection (UHPLC-FLD) has been developed and validated for the determination of Ochratoxin-A (OTA) in rat brain microdialysates and plasma samples. Six adult male wistar rats were used in the study and a single dose (5 mg/kg b.w.) of OTA was given by intraperitoneal (i.p.) injection. Rat blood and microdialysate samples were collected simultaneously after i.p. injection in awake freely moving rats, over a twelve-hour period. An UHPLC analysis was performed on a Zorbax Eclipse Plus C8 (150 mm × 3.0 mm ID × 1.8 µm particles) column with a mobile phase of acetonitrile:water:phosphoric acid (50:50:0.1, v/v) using a flow rate of 0.6 mL/min. The fluorescence detector was set at 330 nm excitation and 460 nm emission wavelengths. Diflunisal (DIF) was used as an internal standard (IS). OTA and IS were separated within 5 min under these conditions. The method was validated in terms of linearity, precision, accuracy, limit of detection, limit of quantification, and stability. Calibration curves obtained with spiked biological matrices show good linearity with high correlation coefficients. The intra- and inter-day assay variability was <5% for the OTA. The limit of detection and the limit of quantification values were found to be 0.490 ng/mL and 1.48 ng/mL for plasma; 0.0900 ng/mL and 0.270 ng/mL for microdialysate samples, respectively. This method was successfully applied for the monitoring of OTA levels in the rat brain and plasma samples.


Assuntos
Química Encefálica , Cromatografia Líquida de Alta Pressão/métodos , Ocratoxinas/análise , Animais , Cromatografia Líquida de Alta Pressão/instrumentação , Limite de Detecção , Masculino , Microdiálise , Ocratoxinas/sangue , Ocratoxinas/farmacocinética , Plasma/química , Ratos , Vigília
18.
Fungal Biol ; 123(8): 611-617, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31345415

RESUMO

The current investigation was aimed to estimate the prevalence and concentration of ochratoxin A (OTA) in different types of coffee and coffee-based products with the aid of a systematic review and meta-analysis. Therefore, the recommended databases including PubMed, Scopus, and Embase from Jan 1983 to Oct 2018 were screened to retrieve the related citations. In this regard, among 1041 explored articles in the identification step, thirty six articles with 3182 samples were included in the meta-analysis and meta-regression. According to findings, the global pooled concentration and prevalence of OTA was calculated as 3.21 µg/kg (95% CI: 3.08-3.34 µg/kg) and 53.0 % (95% CI: 43.0-62.0), respectively. Also, direct correlations between the increases in poverty as well as the amount of annual precipitation and prevalence of OTA was noted, while with decreasing in HDI the prevalence of OTA in coffee significantly was increased. Moreover, the lowest and highest concentrations of OTA in coffee were observed in Taiwan (0.35 µg/kg) and Turkey (79.0 µg/kg), respectively. The outcome of this meta-analysis can be used for the building of risk assessment models aiming to derive data for the development of specific actions to reduce the exposure to this mycotoxin in coffee and coffee-based products.


Assuntos
Coffea/química , Café/química , Contaminação de Alimentos/estatística & dados numéricos , Ocratoxinas/análise , Contaminação de Alimentos/análise , Sementes/química
19.
Food Chem ; 300: 125204, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31336275

RESUMO

Analytical chromatographic techniques for mycotoxins control are well established, but they often depend on costly immunoaffinity sample clean-up. Serum albumins, particularly that from bovine origin (BSA), have stable binding affinity towards some mycotoxins, and can be cheaper alternative receptors for sample clean-up due to their wide availability. Thus, this work used BSA immobilized in agarose beads as a novel solid-phase extraction method for quantification of ochratoxin A (OTA) in wine. Constructed BSA-agarose columns could extract OTA efficiently from red wine after its dilution (4-fold) in 0.1 M Tris pH 8.0. The method was linear (R2 = 0.9999) in the OTA concentration range studied (0.05 to 3.0 µg L-1), with recovery rates above 98%. It also showed low detection (0.017 µg L-1) and quantification (0.051 µg L-1) limits. The efficacy of the BSA-based method was further validated by direct comparison with commercial immunoaffinity columns. Portuguese wines analyzed by both methods had agreeing results.


Assuntos
Contaminação de Alimentos/análise , Ocratoxinas/análise , Soroalbumina Bovina/química , Extração em Fase Sólida/métodos , Vinho/análise , Cromatografia Líquida de Alta Pressão/métodos , Concentração de Íons de Hidrogênio , Limite de Detecção , Micotoxinas/análise , Reprodutibilidade dos Testes , Extração em Fase Sólida/instrumentação
20.
Food Chem ; 300: 125176, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31351258

RESUMO

Mycotoxins are toxic metabolites produced by fungi or molds, which may cause serious harm to human health through polluted cereal foods. In order to measure the typical mycotoxin contaminations in wheat and corn, a surface plasmon resonance (SPR) method was established using SPR sensor chip that was fabricated based on self-assembled monolayer. The minimum detection limit of aflatoxin B1, ochratoxin A, zearalenone and deoxynivalenol were identified as 0.59 ng/mL, 1.27 ng/mL, 7.07 ng/mL and 3.26 ng/mL, respectively. The cross-reactivity for all four mycotoxins were demonstrated to be low. Moreover, the test data were compared with HPLC-MS/MS confirmatory analysis results and good agreement was found between them. In conclusion, the SPR method for simultaneously detecting four mycotoxins has been developed with high sensitivity, good linearity and specificity, which can meet the detection requirements of cereal foods.


Assuntos
Micotoxinas/análise , Ressonância de Plasmônio de Superfície/métodos , Triticum/química , Zea mays/química , Aflatoxina B1/análise , Aflatoxina B1/imunologia , Cromatografia Líquida de Alta Pressão , Reações Cruzadas , Análise de Alimentos/instrumentação , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Hidrazonas/química , Limite de Detecção , Micotoxinas/imunologia , Ocratoxinas/análise , Ocratoxinas/imunologia , Sensibilidade e Especificidade , Ressonância de Plasmônio de Superfície/instrumentação , Espectrometria de Massas em Tandem , Tricotecenos/análise , Tricotecenos/imunologia , Triticum/microbiologia , Zea mays/microbiologia , Zearalenona/análise , Zearalenona/imunologia
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