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1.
Shokuhin Eiseigaku Zasshi ; 60(4): 82-87, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31474655

RESUMO

The Japanese Food Sanitation Act designates the evaporation residue test as a specification for plastics that intended to contact with foods. The test conditions and migration limits for oils and fatty foods were considered on the basis of the results obtained from the evaporation residue test according to the Japanese Act and the overall migration test into olive oil according to EN1186-2. The evaporation residue test was conducted using heptane at 25℃ for 1 hour. The results of most samples were under 30 µg/mL although those of high impact polystyrene,polymethylpentene and polyvinyl chloride were found to be over 30 µg/mL. However, these results were within the acceptable range of the relaxed limits (240, 120, 150 µg/mL). Regarding the overall migration into olive oil, most plastics were under the determination limit at 60℃ for 30 min. But the results for polyethylene, polypropylene and polyvinyl chloride were over 30 µg/mL at 95 and 121℃, which were higher than their evaporation residues. In other words, the existing test conditions and limits of the evaporation residue test could be used for testing plastics that come into contact with oils and fatty foods at lower temperatures. However, they are not adequate for evaluating some plastics that come into contact with oils and fatty foods at higher temperatures.


Assuntos
Contaminação de Alimentos/análise , Embalagem de Alimentos , Óleos Vegetais , Plásticos , Cloreto de Polivinila
2.
Shokuhin Eiseigaku Zasshi ; 60(4): 88-95, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31474656

RESUMO

Microbial colony counts of concern of food products are one of the most important items in microbiological examinations. The distributions of colony counts per agar plate of food samples are considered to be reflected with microbial cell distributions in food homogenates. However, (i) the probabilistic distributions of the colony counts per agar plate at the dilution of counting and (ii) the relationship between the colony counts per plate and the number of agar plates for food samples have not been intensively studied so far. In this study, therefore, these two points were studied with raw food samples of raw minced beef and chicken and raw milk and microbial culture samples of Escherichia coli, Staphylococcus aureus, and Saccharomyces cerevisiae. Among four major probabilistic distributions, it was found that aerobic plate counts per plate of the foods were well described with negative binomial, Poisson, and normal distributions and that the colony counts per plate of microbial cultures were described well with binomial, Poisson, and normal distributions. The effect of the number of agar plates on the estimation of the mean of colony counts per plate of a sample was then studied with the data randomly resampled from the experimental data. The resampled data showed that with more number of plates the mean of counts fluctuated less and the coefficients of variation of colony counts per plate decreased further, which were coincident to the estimated by the central limit theory. Our study would provide useful information on the characteristics of colony counts per plate of food samples which are routinely examined.


Assuntos
Contagem de Colônia Microbiana , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Ágar , Animais , Bovinos , Escherichia coli/isolamento & purificação , Carne/microbiologia , Leite/microbiologia , Saccharomyces cerevisiae/isolamento & purificação , Staphylococcus aureus/isolamento & purificação
4.
Phys Chem Chem Phys ; 21(35): 19288-19297, 2019 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-31451821

RESUMO

This paper reports a facile, fast, and cost-effective method for the synthesis of three-dimensional (3D) porous AgNPs/Cu composites as SERS substrates for the super-sensitive and quantitative detection of food organic contaminations. Due to the 3D porous hotspot architecture and the strong plasmonic coupling between Ag and Cu, the porous AgNPs/Cu substrate achieves ultrasensitive detection of multiple analytes as low as 10-11 M (crystal violet, CV), 10-9 M (malachite green, MG), 10-11 M (acephate), and 10-9 M (thiram) even with a portable Raman device. Moreover, this 3D solid substrate has good signal uniformity (RSD < 11%) and superior stability (<14% signal loss), allowing for practical SERS detections. Importantly, by simply wiping the real sample surface using the substrate, it successfully detects CV and MG residues on crayfish, and the limit of detection (LOD) of CV and MG is determined to be 1.14 × 10-9 M and 0.94 × 10-7 M, respectively. Further, the substrate can also be applied to detect acephate on eggplant with a LOD of 1.41 × 10-9 M and thiram on an apple surface with a LOD of 1.04 × 10-7 M. Note that all these SERS detections on real samples have a broad dynamic concentration range and a good linear dependence. As a "proof of concept", multi-component detection on a real sample has also been demonstrated. This 3D solid substrate possesses excellent detection sensitivity, diversity, and accuracy, which allows rapid and reliable determination of toxic substances in foods.


Assuntos
Técnicas de Química Analítica/métodos , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Praguicidas/análise , Análise Espectral Raman , Animais , Técnicas de Química Analítica/economia , Cobre/química , Limite de Detecção , Nanopartículas Metálicas/química , Reprodutibilidade dos Testes , Prata/química
5.
Shokuhin Eiseigaku Zasshi ; 60(3): 52-60, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31391411

RESUMO

We developed an analytical method for determining 15 antifungal drugs, 2 antiparasitic drugs, and 3 veterinary drugs in fish and livestock products using LC-MS/MS. First, 50% ethanol was added to their products, and the mixture was homogenized to reduce drug degradation. Thereafter, 20 drugs were extracted from the pretreated sample mixture using acetonitrile. Cleanup was performed using an alumina-N SPE cartridge. Finally, chromatographic separation was performed using a fully porous octadecyl silanized silica column. The new method is applicable to fish in which the matrix hampers accurate analysis. It was validated on 8 fish and livestock products. Drug recovery rates ranged from 70.2 to 109.3%, RSDs of repeatability were <18.0%, and RSDs of within-laboratory reproducibility were <18.7%. It fulfills the Japanese guideline criteria. The limits of quantification were estimated as 3 ng/g.


Assuntos
Antifúngicos/análise , Contaminação de Alimentos/análise , Carne/análise , Alimentos Marinhos/análise , Drogas Veterinárias/análise , Animais , Cromatografia Líquida , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem
6.
Niger J Clin Pract ; 22(8): 1083-1090, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31417051

RESUMO

Aims: The aim of this study was to provide epidemiological data about the presence of Salmonella spp. and Shigella spp. in raw milk samples collected from different animals. Methods: A total of 231 raw milk samples from 48 cows, 65 goats, 65 sheep, and 53 donkeys were studied. The ISO 6579:2002 and ISO 21567:2004 methods, antimicrobial susceptibility tests, and serotyping were performed. Species and subspecies discriminations were made via matrix-assisted laser desorption/ionization-time of flight mass spectrometry. After DNA isolation from all samples, Salmonella spp. and Shigella spp. were detected using real-time polymerase chain reaction (PCR) kits. Results: Five samples (2.16%) showed positivity out of 231 raw milk samples for Salmonella spp., and 2 (0.87%) samples were detected to be positive by multiplex real-time PCR design. Conclusion: We found that raw milk samples were not free of Salmonella spp. and Shigella spp. and need to be tested routinely to avoid public health problems. Rapid and reliable real-time PCR method can be developed and used for this purposes instead of slow bacterial culture processes.


Assuntos
DNA Bacteriano/análise , Contaminação de Alimentos/análise , Leite/microbiologia , Reação em Cadeia da Polimerase/métodos , Salmonella/genética , Salmonella/isolamento & purificação , Shigella/genética , Shigella/isolamento & purificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Animais , Bovinos , Equidae , Feminino , Cabras , Humanos , Salmonella/classificação , Sensibilidade e Especificidade , Ovinos , Shigella/classificação
7.
J Agric Food Chem ; 67(33): 9362-9370, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31368700

RESUMO

This manuscript presents an effective and robust method for simultaneous stereoselective determination of two pyrethroid insecticides, tetramethrin and α-cypermethrin in different food products by high-performance liquid chromatography. Enantioseparation was carried out using reversed-phase chromatography, and the influences of four polysaccharide-based chiral columns, mobile phase composition, and column temperature on retention were fully investigated. Satisfactory separation was obtained on Chiralpak IG column using acetonitrile-water (75:25, v/v) under isocratic conditions. To extract and purify the target analytes from food matrices, matrix solid-phase dispersion was employed with C18 as dispersant and primary secondary amine as well as graphitized carbon black as cleanup sorbents. Response surface method based on Box-Behnken design was implemented to assist optimization of the extraction variables. Then, method validation was done in real samples including specificity, linearity, sensitivity, trueness, precision, as well as stability, and its analytical performance fulfills the criteria recommended by the European Union SANTE/11945/2015, demonstrating its applicability in studying the stereochemistry of chiral tetramethrin and α-cypermethrin in food products.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Grão Comestível/química , Frutas/química , Inseticidas/química , Piretrinas/química , Verduras/química , Cromatografia de Fase Reversa/métodos , Contaminação de Alimentos/análise , Inseticidas/isolamento & purificação , Piretrinas/isolamento & purificação , Extração em Fase Sólida , Estereoisomerismo
8.
J Agric Food Chem ; 67(33): 9203-9209, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31369261

RESUMO

With the monitoring of hundreds of pesticides in food and feed, the comminution step is equally crucial as any other to achieve valid results. However, sample processing is often underestimated in its importance and practical difficulty to produce consistent test portions for analysis. The scientific literature is rife with descriptions of microextraction methods, but ironically, sample comminution is often ignored or dismissed as being prosaic, despite it being the foundation upon which the viability of such techniques relies. Cryogenic sample processing using dry ice (-78 °C) is generally accepted in practice, but studies have not shown it to yield representative test portions of <1 g. Remarkably, liquid nitrogen has rarely been used as a cryogenic agent in pesticide residue analysis, presumably as a result of access, cost, and safety concerns. However, real-world implementation of blending unfrozen bulk food portions with liquid nitrogen (-196 °C) using common food processing devices has demonstrated this approach to be safe, simple, fast, and cost-effective and yield high-quality results for various commodities, including increased stability of labile or volatile analytes. For example, analysis of dithiocarbamates as carbon disulfide has shown a significant increase of thiram recoveries (up to 95%) using liquid nitrogen during sample comminution. This perspective is intended to allay concerns among working laboratories about the practical use of liquid nitrogen for improved sample processing in the routine monitoring of pesticide residues in foods and feeds, which also gives promise for feasible test sample size reduction in high-throughput miniaturized methods.


Assuntos
Ração Animal/análise , Contaminação de Alimentos/análise , Liofilização/métodos , Resíduos de Praguicidas/análise , Gelo-Seco , Liofilização/instrumentação , Frutas/química , Nitrogênio/química
9.
J Agric Food Chem ; 67(29): 8279-8289, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31259549

RESUMO

This study is focused on examining the tocopherol isomers (α-, γ-, and δ-) fingerprinting by online RP-HPLC analysis with post column detection using CUPRAC (cupric reducing antioxidant capacity) methodology for argan oil authenticity. The proposed online assay was validated with good precision, reproducibility, and linearity. Sixteen argan oil samples (100% pure-certified and other commercial argan oils), possible adulterating vegetable oils (i.e., olive, sunflower, corn, and soya oils), and virgin argan oil blended with olive, sunflower, corn, and soya oils at levels of 5%, 10%, 15%, and 20% were analyzed. Spectrophotometric CUPRAC, DPPH, and ABTS assays were applied. Discrimination of fraudulent argan oils from virgin samples was performed by utilizing orthogonal partial least-squares discriminant analysis (OPLS-DA) regression modeling with good sensitivity and specificity. We suggested [γ-toc/α-toc] value as a new first screening adulteration factor (AF) that could be used to assess fraudulent argan oil samples. The distinct decrement in AF value was observed by the increase of adulteration rate. The AF values for virgin argan oils were ranged from 11.8 (lower limit) to 18.6 (upper limit). The presence of ß-sitosterol detected in commercial argan oils (with AF values out of limit values) was evaluated as fraudulent which was in accordance with the proposed assay. Our method enabled the detection of argan oil samples at adulteration levels of >5% in the case of sunflower, olive, and soya oils, >15% in the case of corn oil. This method may be an alternative and specific assay for the authentication and quality detection of commercial argan oils.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Óleos Vegetais/análise , Análise Discriminante , Contaminação de Alimentos/análise , Análise dos Mínimos Quadrados , Reprodutibilidade dos Testes , Tocoferóis/análise
10.
J Agric Food Chem ; 67(29): 8268-8278, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31283221

RESUMO

Species authentication of meat and fish products is crucial to safeguard public health, economic investment, and religious sanctity. We developed a heptaplex polymerase chain reaction assay targeting short amplicon length (73-198 bp) for the simultaneous detection and differentiation of cow, buffalo, chicken, cat, dog, pig, and fish species in raw and processed food using species-specific primers targeting mitochondrial cytb, ND5, and 16s rRNA genes. Assay validation of adulterated and various heat-treated meatball matrices showed excellent stability and sensitivity under all processing conditions. The detection limit was 0.01-0.001 ng of DNA under pure states and 0.5% meat in meatball products. Buffalo was detected in 86.7% (13 out of 15) of tested commercial beef products, while chicken, pork, and fish products were found to be pure. The developed assay was efficient enough to detect target species simultaneously, even in highly degraded and processed food products at reduced time.


Assuntos
Contaminação de Alimentos/análise , Produtos da Carne/análise , Reação em Cadeia da Polimerase/métodos , Animais , Búfalos/genética , Gatos/genética , Bovinos/genética , Galinhas/genética , Cães/genética , Peixes/genética , Suínos/genética
11.
J Agric Food Chem ; 67(29): 8253-8267, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31294564

RESUMO

The study focused on the determination of arsenic species in the top ten most consumed seafoods in the United States. Fifty-four samples were collected from local supermarkets, and their species identities were confirmed by DNA barcoding. The total arsenic in the samples varied greatly in the range of 8-22200 ng/g (wet mass). Speciation analysis based on extraction of water-soluble and nonpolar arsenic showed that inorganic arsenic (iAs) was found only in clams and crabs, while arsenobetaine (AsB) predominates in most samples. Among the other arsenicals, trimethylarsoniopropionate (TMAP) was found in most matrices with higher concentrations in crabs, and arsenosugars existed in most clams and crabs. Nonpolar arsenic accounted for 1-46% of the total arsenic in the samples. The accuracy of the analytical results was evaluated using standard reference materials and spike recovery tests. The survey showed that the iAs concentrations in America's most consumed seafood products are much lower than the tolerable intake set by the Joint FAO/WHO Expert Committee, even at the highest levels found in this study.


Assuntos
Arsênico/química , Contaminação de Alimentos/análise , Alimentos Marinhos/análise , Animais , Bivalves/química , Braquiúros/química , Qualidade de Produtos para o Consumidor , Contaminação de Alimentos/economia , Contaminação de Alimentos/estatística & dados numéricos , Espectrometria de Massas , Alimentos Marinhos/economia , Estados Unidos
12.
Toxicol Lett ; 314: 117-123, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31325634

RESUMO

The Threshold of Toxicological Concern (TTC) concept integrates data on exposure, chemical structure, toxicity and metabolism to identify a safe exposure threshold value for chemicals with insufficient toxicity data for risk assessment. The TTC values were originally derived from a non-cancer dataset of 613 compounds with a potentially small domain of applicability. There is interest to test whether the TTC values are applicable to a broader range of substances, particularly relevant to food safety using EFSA's new OpenFoodTox database. After exclusion of genotoxic compounds, organophosphates or carbamates or those belonging to the TTC exclusion categories, the remaining 329 substances in the EFSA OpenFoodTox database were categorized under the Cramer decision tree, into low (Class I), moderate (II), or high (III) toxicity profile. For Cramer Classes I and III the threshold values were 1000 µg/person per day (90% confidence interval: 187-2190) and 87 µg/person per day (90% confidence interval: 60-153), respectively, compared to the corresponding original threshold values of 1800 and 90 µg/person per day. This confirms the applicability of the TTC values to substances relevant to food safety. Cramer Class II was excluded from our analysis because of containing too few compounds. Comparison with the Globally Harmonized System of classification confirmed that the Cramer classification scheme in the TTC approach is conservative for substances relevant to food safety.


Assuntos
Exposição Dietética/efeitos adversos , Contaminação de Alimentos/análise , Alimentos/efeitos adversos , Substâncias Perigosas/toxicidade , Terminologia como Assunto , Consenso , Bases de Dados Factuais , Alimentos/classificação , Substâncias Perigosas/classificação , Humanos , Nível de Efeito Adverso não Observado , Medição de Risco
13.
Chem Commun (Camb) ; 55(62): 9160-9163, 2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-31304937

RESUMO

The rational design of heteroatom-doped C3N4 offers a great opportunity to optimize C3N4 performance. In this communication, we propose a facile method to fabricate layered-stacked B-doped C3N4 (BCN-800) ultrathin nanosheets via a one-step calcination route. The distinctive layered-stacked structure and the presence of B atoms provide an active attachment point for antibodies and antigens. In addition, the presence of C and N might aid stability and increase conductivity. When used for vomitoxin detection, the BCN-800-based electrochemical biosensor exhibits high sensitivity with a detection limit of 0.32 pg mL-1 and superior selectivity to other interfering agents.


Assuntos
Técnicas Biossensoriais , Boro/química , Ácidos Borônicos/química , Contaminação de Alimentos/análise , Inocuidade dos Alimentos/métodos , Nitrilos/síntese química , Tricotecenos/análise , Técnicas Eletroquímicas , Nitrilos/química , Tamanho da Partícula , Propriedades de Superfície
14.
J Agric Food Chem ; 67(28): 8007-8019, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31268702

RESUMO

Cow and human milk have been reported to contain dioxins ranging from 0.023 to 26.46 and 0.88 to 19 pg/g of fat, respectively. However, the toxic effects of the dioxins in the milk in this range of concentrations were not explored. Therefore, considering the outbred livestock tissues as better models than inbred laboratory animals, the present study targeted to study the effect of dioxins present in the milk on three-dimensionally (3D) cultured buffalo primary hepatocyte spheroids. The spheroids were treated with a model dioxin, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), directly and also through milk fat at different concentrations (i.e, 0.02-20 pg/mL) for 24 h. Among the liver-cell-specific (ALB, HNF4α, and AFP) genes, a similar ALB and upregulated HNF4α expression at all treatments indicated the functional and transcriptionally active hepatocyte spheroids. Supportingly, no significant difference in the antiapoptotic gene expression between the treatments of milk fat and milk fat containing dioxins indicated the survivability of the spheroids during dioxin treatments. Among the selected TCDD responsive (CYP1A1, CYP1A2, AHR, CYP1B1, and TIPARP) genes, a nonsignificant increasing trend of the CYP1A1 expression was observed from 0.2 to 10 pg/mL of TCDD concentration through milk fat. This pattern was similar to the reported insensitive response of human primary hepatocytes toward dioxins than that of rat primary hepatocytes. This may indicate that the buffalo hepatocyte spheroids could be better models than rats for TCDD hepatotoxic studies. Further, TCDD in the milk in the range of 0.02-20 pg/mL concentration may not be very hepatotoxic.


Assuntos
Dioxinas/farmacologia , Hepatócitos/efeitos dos fármacos , Leite/química , Animais , Búfalos , Células Cultivadas , Citocromo P-450 CYP1A1/genética , Citocromo P-450 CYP1A1/metabolismo , Citocromo P-450 CYP1A2/genética , Citocromo P-450 CYP1A2/metabolismo , Dioxinas/análise , Contaminação de Alimentos/análise , Fator 4 Nuclear de Hepatócito/genética , Fator 4 Nuclear de Hepatócito/metabolismo , Hepatócitos/metabolismo , Fígado/citologia , Fígado/efeitos dos fármacos , Fígado/metabolismo , Modelos Animais , Ratos , Esferoides Celulares/efeitos dos fármacos , Esferoides Celulares/metabolismo , alfa-Fetoproteínas/genética , alfa-Fetoproteínas/metabolismo
15.
J Agric Food Chem ; 67(32): 9032-9038, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31334646

RESUMO

It is estimated that approximately 200 million people are exposed to arsenic levels above the World Health Organization provisional guideline value, and various agencies have indicated the need to reduce this exposure. In view of the difficulty of removing arsenic from water and food, one alternative is to reduce its bioavailability (the amount that reaches the systemic circulation after ingestion). In this study, dietary components [glutathione, tannic acid, and Fe(III)] were used to achieve this goal. As(III) or As(V) (1 mg/kg body weight) was administered daily to BALB/c mice, along with the dietary components, for 15 days. The results confirm the efficacy of Fe(III) and glutathione as reducers of arsenic bioavailability and tissue accumulation. Also, these treatments did not result in reductions of Ca, K, P, and Fe contents in the liver. These data suggest that use of these two compounds could be part of valid strategies for reducing inorganic arsenic exposure in chronically exposed populations.


Assuntos
Arsenicais/metabolismo , Compostos Férricos/química , Glutationa/química , Animais , Arsenicais/química , Disponibilidade Biológica , Exposição Dietética/análise , Exposição Dietética/prevenção & controle , Compostos Férricos/metabolismo , Contaminação de Alimentos/análise , Glutationa/metabolismo , Fígado/metabolismo , Pulmão/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Oryza/química , Oryza/metabolismo
16.
J Agric Food Chem ; 67(32): 9104-9111, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31334655

RESUMO

Gold nanoflowers (GNFs) exhibit stronger light scattering ability than gold nanospheres (GNSs) with the same diameter, thereby contributing to enhancing the sensitivity of the scattering-based sensing method. However, the application of GNFs in biosensors based on dynamic light scattering (DLS) has not been yet reported. Herein, we describe for the first time an improved no-wash immunosensor based on dynamic light scattering for the detection of Escherichia coli O157:H7 (E. coli O157:H7) in milk using GNFs for sensitive signal transduction. To achieve this goal, a thiolated amphiphilic carboxyl ligand was introduced to modify the GNF surface and improve solution stability and antibody functionalization. Several key factors that affect the detection sensitivity of our developed GNF_DLS immunosensor were systematically investigated. Under the optimal conditions, our proposed GNF_DLS immunosensor provided an excellent linear detection for E. coli O157:H7 within the range from 6 × 100 to 6 × 104 colony-forming units (CFU)/mL, with a limit of detection of 2.7 CFU/mL. Combined with our previously reported two-step large-volume immunomagnetic separation (IMS) method, the designed GNF_DLS immunosensor can sensitively, selectively, and accurately detect the presence of E. coli O157:H7 in pasteurized milk. The potential of our GNF_DLS method for monitoring the presence of a single bacterial cell in 1 mL of sample solution was also demonstrated. Overall, the developed GNF_DLS immunosensor can be used for the rapid and high-sensitivity determination of pathogenic bacteria and can be extended for the ultrasensitive no-wash detection of other trace analytes.


Assuntos
Técnicas Biossensoriais/métodos , Difusão Dinâmica da Luz/métodos , Escherichia coli O157/isolamento & purificação , Leite/microbiologia , Animais , Técnicas Biossensoriais/instrumentação , Bovinos , Difusão Dinâmica da Luz/instrumentação , Escherichia coli O157/crescimento & desenvolvimento , Contaminação de Alimentos/análise , Ouro/química , Leite/química , Nanoestruturas/química , Sensibilidade e Especificidade
17.
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
18.
J Agric Food Chem ; 67(32): 9088-9095, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31347836

RESUMO

Triclocarban (TCC) and triclosan (TCS) have been simultaneously detected in five kinds of foodstuffs using an immunoaffinity purification method coupled with ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) for the first time. Two highly specific monoclonal antibodies against TCC and TCS were produced and coupled to N-hydroxysuccinimide-activated Sepharose 6B gel to prepare the immunosorbent. Under the optimal conditions, mean recoveries from spiked samples by the IAC-UHPLC-MS/MS method were 70.1-92.8% for TCC and 76.6-102.5% for TCS. Intraday relative standard deviations were below 14.5%. The limits of quantification (LOQs) of TCC were 1 ng/L for beverage samples and 0.01-0.02 µg/kg for food samples. The LOQs of TCS were 0.03 µg/L for beverage samples and 0.2-0.3 µg/kg for food samples. The applicability of the method has been proven by analyzing TCC and TCS in different samples from supermarkets in Beijing. The proposed method is sufficiently sensitive and reliable for monitoring trace concentrations of TCC and TCS in food samples.


Assuntos
Antibacterianos/análise , Carbanilidas/análise , Cromatografia de Afinidade/métodos , Cromatografia Líquida de Alta Pressão/métodos , Espectrometria de Massas em Tandem/métodos , Triclosan/análise , Antibacterianos/isolamento & purificação , Bebidas/análise , Carbanilidas/isolamento & purificação , Contaminação de Alimentos/análise , Técnicas de Imunoadsorção , Triclosan/isolamento & purificação
19.
J Agric Food Chem ; 67(32): 9096-9103, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31356079

RESUMO

A monoclonal antibody (mAb) was raised against tebuconazole (TEB) using a hapten where the p-chloro substituent of the TEB molecule was replaced with a long-chain carboxylic acid. The resulting mAb showed high sensitivity and specificity against TEB characterized by ELISA with a half-maximal inhibitory concentration (IC50) of 0.19 ng mL-1 and with cross-reactivity (CR) values below 0.01% to several analogues of triazole fungicides. On the basis of the mAb produced, a quantum dot beads-based fluorescence immunochromatographic test strip assay (QBs-FITSA) was developed for rapid and sensitive detection of TEB in agricultural product samples. The QBs-FITSA exhibited a linear detection range from 0.02 to 1.25 ng mL-1 with a limit of detection (LOD) of 0.02 ng mL-1. Furthermore, using produced mAb, multiple high-throughput rapid immunoassay formats could be achieved as a convenient monitoring tool for evaluation of human and environmental exposure to TEB.


Assuntos
Brassica/química , Cucumis sativus/química , Fungicidas Industriais/análise , Imunoensaio/métodos , Triazóis/análise , Triticum/química , Anticorpos Monoclonais/análise , Contaminação de Alimentos/análise , Fungicidas Industriais/isolamento & purificação , Imunoensaio/instrumentação , Limite de Detecção , Pontos Quânticos/química , Triazóis/isolamento & purificação
20.
Se Pu ; 37(7): 712-722, 2019 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-31271010

RESUMO

A liquid chromatography-tandem mass spectrometry method for the identification of marker peptides of aquatic product allergens and quantitative detection of multiple allergens in meat products and seasonings was developed. The samples were prepared by protein extraction, protein purification, and trypsin hydrolysis. The proteins and peptides were identified using ProteinPilot by the data analysis of the ion spectrum of polypeptide fragments using ultra-performance liquid chromatography-quadrupole/electrostatic orbitrap high-resolution mass spectrometry (UPLC-Q/Exactive-HRMS). The identification of 30 species-specific marker peptides in Penaeus vannamei, Eriocheir, Scylla serrata, Thunnus thynnus, and Atlantic salmon by comparison of the basic local alignment search tool (BLAST) with the UniProt database was achieved. The verification and multiple reaction monitoring (MRM) quantitative studies of these marker peptides were performed using a triple quadrupole mass spectrometry (UPLC-QqQ-MS) system. The proposed method showed a good linear relationship in the range of 5-250 mg/kg. The limits of quantitation and observed recoveries were in the range of 2-3.5 mg/kg and 88.7%-110.2%, respectively. This method presents various advantages such as good repeatability and high throughput, suitability for rapid screening, and quantitative analysis of seven aquatic allergens in meat products and seasonings.


Assuntos
Alérgenos/análise , Proteínas de Peixes/análise , Contaminação de Alimentos/análise , Produtos da Carne/análise , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Espectrometria de Massas em Tandem
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