Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 41
Filtrar
1.
Sensors (Basel) ; 23(11)2023 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-37299875

RESUMO

This study is directed towards developing a fast, non-destructive, and easy-to-use handheld multimode spectroscopic system for fish quality assessment. We apply data fusion of visible near infra-red (VIS-NIR) and short wave infra-red (SWIR) reflectance and fluorescence (FL) spectroscopy data features to classify fish from fresh to spoiled condition. Farmed Atlantic and wild coho and chinook salmon and sablefish fillets were measured. Three hundred measurement points on each of four fillets were taken every two days over 14 days for a total of 8400 measurements for each spectral mode. Multiple machine learning techniques including principal component analysis, self-organized maps, linear and quadratic discriminant analyses, k-nearest neighbors, random forest, support vector machine, and linear regression, as well as ensemble and majority voting methods, were used to explore spectroscopy data measured on fillets and to train classification models to predict freshness. Our results show that multi-mode spectroscopy achieves 95% accuracy, improving the accuracies of the FL, VIS-NIR and SWIR single-mode spectroscopies by 26, 10 and 9%, respectively. We conclude that multi-mode spectroscopy and data fusion analysis has the potential to accurately assess freshness and predict shelf life for fish fillets and recommend this study be expanded to a larger number of species in the future.


Assuntos
Inteligência Artificial , Peixes , Animais , Espectrometria de Fluorescência/métodos
2.
Environ Sci Technol ; 53(18): 10803-10812, 2019 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-31378062

RESUMO

Hydrophilic divinylbenzene (DVB) (Bakerbond) has surfaced as a promising sorbent for active sampling of analytes from aqueous matrices over a very broad polarity range. Given this, hydrophilic DVB may likewise offer potential for passive sampling, if sorbent/water partitioning coefficients (Ksw) were to be available. In this work, static exposure batch experiments were performed to quantitatively study the equilibrium sorption of 131 environmentally relevant organic contaminants (P values ranging from -1.30 to 9.85) on hydrophilic DVB. The superior affinity of hydrophilic DVB, as compared to Oasis HLB, for compounds with a broad polarity range was confirmed by functional Fourier-transform infrared spectroscopy and Raman characterization, demonstrating the presence of carboxyl moieties. Concentration effects were studied by increasing compound concentrations in mixture experiments and resulted in the steroidal endocrine disrupting compounds in higher Ksw, while lower Ksw were obtained for the (alkyl)phenols, personal care products, pesticides, pharmaceuticals, and phthalates. Nevertheless, Ksw remained constant in the said design for equilibrium water concentrations at environmentally relevant seawater levels. An independent analysis of thermodynamic parameters (change in enthalpy, entropy, and Gibbs free energy) revealed the nature of the main partitioning processes. While polar (log P < 4) compounds were mainly served by physisorption, nonpolar (log P > 4) compounds also exhibited binding by multiple hydrogen bonding. In conclusion, this research facilitates the future application of hydrophilic DVB for active as well as passive sampling in the analysis of organic contaminants for monitoring purposes and for toxicity testing.


Assuntos
Praguicidas , Poluentes Químicos da Água , Interações Hidrofóbicas e Hidrofílicas , Compostos de Vinila
3.
Anal Bioanal Chem ; 407(21): 6447-61, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26123435

RESUMO

In the context of products from certain regions or countries being banned because of an identified or non-identified hazard, proof of geographical origin is essential with regard to feed and food safety issues. Usually, the product labeling of an affected feed lot shows origin, and the paper documentation shows traceability. Incorrect product labeling is common in embargo situations, however, and alternative analytical strategies for controlling feed authenticity are therefore needed. In this study, distillers' dried grains and solubles (DDGS) were chosen as the product on which to base a comparison of analytical strategies aimed at identifying the most appropriate one. Various analytical techniques were investigated for their ability to authenticate DDGS, including spectroscopic and spectrometric techniques combined with multivariate data analysis, as well as proven techniques for authenticating food, such as DNA analysis and stable isotope ratio analysis. An external validation procedure (called the system challenge) was used to analyze sample sets blind and to compare analytical techniques. All the techniques were adapted so as to be applicable to the DDGS matrix. They produced positive results in determining the botanical origin of DDGS (corn vs. wheat), and several of them were able to determine the geographical origin of the DDGS in the sample set. The maintenance and extension of the databanks generated in this study through the analysis of new authentic samples from a single location are essential in order to monitor developments and processing that could affect authentication.


Assuntos
Grão Comestível/química , Etanol/química , Solubilidade
4.
Adv Mater ; 36(15): e2309625, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38224595

RESUMO

The implementation of low-cost and rapid technologies for the on-site detection of mycotoxin-contaminated crops is a promising solution to address the growing concerns of the agri-food industry. Recently, there have been significant developments in surface-enhanced Raman spectroscopy (SERS) for the direct detection of mycotoxins in food and feed. This review provides an overview of the most recent advancements in the utilization of SERS through the successful fabrication of novel nanostructured materials. Various bottom-up and top-down approaches have demonstrated their potential in improving sensitivity, while many applications exploit the immobilization of recognition elements and molecular imprinted polymers (MIPs) to enhance specificity and reproducibility in complex matrices. Therefore, the design and fabrication of nanomaterials is of utmost importance and are presented herein. This paper uncovers that limited studies establish detection limits or conduct validation using naturally contaminated samples. One decade on, SERS is still lacking significant progress and there is a disconnect between the technology, the European regulatory limits, and the intended end-user. Ongoing challenges and potential solutions are discussed including nanofabrication, molecular binders, and data analytics. Recommendations to assay design, portability, and substrate stability are made to help improve the potential and feasibility of SERS for future on-site agri-food applications.


Assuntos
Micotoxinas , Nanoestruturas , Análise Espectral Raman/métodos , Reprodutibilidade dos Testes , Alimentos
5.
Anal Bioanal Chem ; 405(24): 7753-63, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23812877

RESUMO

Tetrodotoxin (TTX) is a potent neurotoxin emerging in European waters due to increasing ocean temperatures. Its detection in seafood is currently performed as a consequence of using the Association of Analytical Communities (AOAC) mouse bioassay (MBA) for paralytic shellfish poisoning (PSP) toxins, but TTX is not monitored routinely in Europe. Due to ethical and performance-related issues associated with this bioassay, the European Commission has recently published directives extending procedures that may be used for official PSP control. An AOAC-accredited high-performance liquid chromatography (HPLC) method has now been accepted by the European Union as a first action screening method for PSP toxins to replace the MBA. However, this AOAC HPLC method is not capable of detecting TTX, so this potent toxin would be undetected; thereby, a separate method of analysis is required. Surface plasmon resonance (SPR) optical biosensor technology has been proven as a potential alternative screening method to detect PSP toxins in seafood. The addition of a similar SPR inhibition assay for TTX would complement the PSP assay in removing the MBA. The present report describes the development and single laboratory validation in accordance with AOAC and IUPAC guidelines of an SPR method to be used as a rapid screening tool to detect TTX in the sea snail Charonia lampas lampas, a species which has been implicated in 2008 in the first case of human TTX poisoning in Europe. As no current regulatory limits are set for TTX in Europe, single laboratory validation was undertaken using those for PSP toxins at 800 µg/kg. The decision limit (CCα) was 100 µg/kg, with the detection capability (CCß) found to be ≤200 µg/kg. Repeatability and reproducibility were assessed at 200, 400, and 800 µg/kg and showed relative standard deviations of 8.3, 3.8, and 5.4% and 7.8, 8.3, and 3.7% for both parameters at each level, respectively. At these three respective levels, the recovery of the assay was 112, 98, and 99%.


Assuntos
Bioensaio/métodos , Inocuidade dos Alimentos/métodos , Frutos do Mar , Tetrodotoxina/análise , Animais , Europa (Continente) , Humanos , Limite de Detecção , Camundongos , Modelos Moleculares , Óptica e Fotônica , Fatores de Risco , Tetrodotoxina/química
6.
Foods ; 12(24)2023 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-38137302

RESUMO

There is a growing demand from consumers for more assurance in premium food products such as beef and especially steak. The quality of beef steak is primarily dictated by the maturation which ultimately influences its taste and flavor. These enhanced qualities have resulted in steak becoming a premium product that consumers are willing to pay a premium price for. A challenge, however, is analyzing the maturity of beef by traditional analytical techniques. Hyperspectral imaging (HSI) is a methodology that is gaining traction mainly due to miniaturization, improved optics, and software. In this study, HSI was applied to wet aged beef supplied at various stages of maturity, with spectral data generated using a portable hyperspectral camera. Two trials were conducted over a five-month period: (i) proof of principle and (ii) a bespoke sampling trial for the industry. With the support of industry participation, all samples were sourced from a highly reputable UK/Ireland supplier. To enhance data interpretation, the spectral data collected were combined with multivariate analysis. A range of chemometric models were generated using unsupervised and supervised methods to determine the maturity of the beef, and external validation was performed. The external validation showed good accuracy for "unknown samples" tested against the model set and ranged from 74 to 100% for the different stages of maturity (20, 30, and 40 days old). This study demonstrated that HSI can detect different maturity timepoints for beef samples, which could play an important role in solving some of the challenges that the industry faces with ensuring the authenticity of their products. This is the first time that portable HSI has been coupled with chemometric modeling for assessing the maturity of beef, and it can serve as a model for other food authenticity and quality applications.

7.
NPJ Sci Food ; 7(1): 40, 2023 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-37567867

RESUMO

Risk communication is defined as the interactive exchange of information and opinions concerning risk, risk-related factors and risk perceptions amongst all the stakeholders of food safety throughout the risk analysis process. The interactive exchange of information occurs at three different levels i.e. informed level, dialogue level and engagement level. For an effective food safety risk communication (FSRC), it is important that the information should adhere to the core principles of risk communication which are transparency, openness, responsiveness and timeliness. Communication of a food safety risk within all the components of risk communication strategy constitutes a complex network of information flow that can be better understood with the help of a framework. Therefore, a model framework to communicate the risks associated with aflatoxins (AFs) dietary intake has been developed with the aim of (a) creating general awareness amongst public and (b) involving industry stakeholders in the prevention and control of risk. The framework has been motivated by the learnings and best practices outlined in the identified technical guidance documents for risk communication. Risk assessors, risk managers, industry stakeholders and general public have been identified as the major stakeholders for the present framework. Amongst them, industry stakeholders and general public has been selected as the major target audience for risk managers. Moreover, population residing in low- and middle-income countries (LMIC) has been identified as the main target group to reach.

8.
Org Biomol Chem ; 10(36): 7292-304, 2012 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-22878622

RESUMO

Enzymatic cis-dihydroxylation of benzo[b]thiophene, benzo[b]furan and several methyl substituted derivatives was found to occur in both the carbocyclic and heterocyclic rings. Relative and absolute configurations and enantiopurities of the resulting dihydrodiols were determined. Hydrogenation of the alkene bond in carbocyclic cis-dihydrodiols and ring-opening epimerization/reduction reactions of heterocyclic cis/trans-dihydrodiols were also studied. The relatively stable heterocyclic dihydrodiols of benzo[b]thiophene and benzo[b]furan showed a strong preference for the trans configuration in aqueous solutions. The 2,3-dihydrodiol metabolite of benzo[b]thiophene was utilized as a precursor in the chemoenzymatic synthesis of the unstable arene oxide, benzo[b]thiophene 2,3-oxide.


Assuntos
Benzofuranos/metabolismo , Biocatálise , Oxigenases/metabolismo , Tiofenos/metabolismo , Benzofuranos/química , Cristalografia por Raios X , Hidroxilação , Modelos Moleculares , Estrutura Molecular , Estereoisomerismo , Tiofenos/química
9.
Org Biomol Chem ; 10(4): 782-90, 2012 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-22134441

RESUMO

Asymmetric heteroatom oxidation of benzo[b]thiophenes to yield the corresponding sulfoxides was catalysed by toluene dioxygenase (TDO), naphthalene dioxygenase (NDO) and styrene monooxygenase (SMO) enzymes present in P. putida mutant and E. coli recombinant whole cells. TDO-catalysed oxidation yielded the relatively unstable benzo[b]thiophene sulfoxide; its dimerization, followed by dehydrogenation, resulted in the isolation of stable tetracyclic sulfoxides as minor products with cis-dihydrodiols being the dominant metabolites. SMO mainly catalysed the formation of enantioenriched benzo[b]thiophene sulfoxide and 2-methyl benzo[b]thiophene sulfoxides which racemized at ambient temperature. The barriers to pyramidal sulfur inversion of 2- and 3-methyl benzo[b]thiophene sulfoxide metabolites, obtained using TDO and NDO as biocatalysts, were found to be ca.: 25-27 kcal mol(-1). The absolute configurations of the benzo[b]thiophene sulfoxides were determined by ECD spectroscopy, X-ray crystallography and stereochemical correlation. A site-directed mutant E. coli strain containing an engineered form of NDO, was found to change the regioselectivity toward preferential oxidation of the thiophene ring rather than the benzene ring.


Assuntos
Dioxigenases/metabolismo , Escherichia coli/enzimologia , Complexos Multienzimáticos/metabolismo , Oxigenases/metabolismo , Pseudomonas putida/enzimologia , Sulfóxidos/metabolismo , Tiofenos/metabolismo , Cristalografia por Raios X , Oxirredução , Sulfóxidos/química , Tiofenos/química
10.
NPJ Sci Food ; 6(1): 3, 2022 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-35027565

RESUMO

Pesticides are a safety issue globally and cause serious concerns for the environment, wildlife and human health. The handheld detection of four pesticide residues widely used in Basmati rice production using surface-enhanced Raman spectroscopy (SERS) is reported. Different SERS substrates were synthesised and their plasmonic and Raman scattering properties evaluated. Using this approach, detection limits for pesticide residues were achieved within the range of 5 ppb-75 ppb, in solvent. Various extraction techniques were assessed to recover pesticide residues from spiked Basmati rice. Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERs) acetate extraction was applied and characteristic spectral data for each pesticide was obtained from the spiked matrix and analysed using handheld-SERS. This approach allowed detection limits within the matrix conditions to be markedly improved, due to the rapid aggregation of nanogold caused by the extraction medium. Thus, detection limits for three out of four pesticides were detectable below the Maximum Residue Limits (MRLs) of 10 ppb in Basmati rice. Furthermore, the multiplexing performance of handheld-SERS was assessed in solvent and matrix conditions. This study highlights the great potential of handheld-SERS for the rapid on-site detection of pesticide residues in rice and other commodities.

11.
Anal Chem ; 83(12): 5012-6, 2011 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-21557539

RESUMO

The illegal adulteration of milk with melamine in 2008 in China led to adverse kidney and urinary tract effects in hundreds of thousands of children and the reported deaths of six. The milk had been deliberately adulterated to elevate the apparent protein content, and subsequently melamine was detected in many milk-related products which had been exported. This led to the banning of imports of milk and milk products from China intended for the nutritional use of children and to the implementation of analytical methods to test products containing milk products. An optical biosensor inhibition immunoassay has been developed as a rapid and robust method for the analysis of infant formula and infant liquid milk samples. A compound with a chemical structure similar to that of melamine was employed as a hapten to raise a polyclonal antibody and as the immobilized antigen on the surface of a biosensor chip. The sensitivity of the assay, given as an IC(50), was calculated to be 67.9 ng mL(-1) in buffer. The antibody did not cross-react with any of the byproducts of melamine manufacture; however, significant cross-reactivity was observed with the insecticide cyromazine of which melamine is a metabolite. When sample matrix was applied to the assay, a limit of detection of <0.5 µg mL(-1) was determined in both infant formula and infant liquid milk. The development of the immunoassay and validation data for the detection of melamine is presented together with the results obtained following the analysis of melamine-contaminated milk powder.


Assuntos
Técnicas Biossensoriais/métodos , Imunoensaio/métodos , Fórmulas Infantis/química , Triazinas/análise , Anticorpos/imunologia , Antígenos/química , Antígenos/imunologia , Haptenos/química , Haptenos/imunologia , Humanos , Lactente
12.
Anal Chem ; 83(11): 4206-13, 2011 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-21495670

RESUMO

A surface plasmon resonance (SPR) optical biosensor method was developed for the detection of paralytic shellfish poisoning (PSP) toxins in shellfish. This application was transferred in the form of a prototype kit to seven laboratories using Biacore Q SPR optical biosensor instrumentation for interlaboratory evaluation. Each laboratory received 20 shellfish samples across a range of species including blind duplicates for analysis. The samples consisted of 4 noncontaminated samples spiked in duplicate with a low level of PSP toxins (240 µg STXdiHCl equivalents/kg), a high level of saxitoxin (825 µg STXdiHCl/kg), 2 noncontaminated, and 14 naturally contaminated samples. All 7 participating laboratories completed the study, and HorRat values obtained were <1 demonstrating that the method performance was acceptable. Mean recoveries expressed as STXdiHCl equivalents/kg were 94.6 ± 16.8% for the low level PSP toxin mix and 98.6 ± 5.6% for the high level of saxitoxin. Relative standard deviations for within-laboratory variations (RSD(r): repeatability) and between-laboratory variations (RSD(R) = reproducibility) ranged from 1.8 to 9.6% and 2.9 to 18.3% respectively. This first ever reported SPR biosensor interlaboratory study demonstrated this PSP application to be an empowering tool in the drive toward the reduction and replacement of the mouse bioassay within Europe.


Assuntos
Toxinas Marinhas/análise , Frutos do Mar/análise , Ressonância de Plasmônio de Superfície/métodos , Técnicas Biossensoriais/métodos , Laboratórios , Projetos Piloto , Saxitoxina/análise
13.
Anal Bioanal Chem ; 399(6): 2275-84, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21221551

RESUMO

A fluorescence polarization immunoassay (FPIA) based on a polyclonal antibody was developed for the determination of melamine in milk. To obtain an antibody with improved sensitivity and specificity, 6-hydrazinyl-1,3,5-triazine-2,4-diamine was coupled to bovine serum albumin and used as the immunogen for the rabbit immunization. Three fluorescein-labeled melamine tracers with different structures and spacer bridges were synthesized. The structural effect of the tracers on the assay characteristics was investigated. 6-(4,6-Diamino-1,3,5-triazin-2-ylamino)-N-(2-(3-(3',6'-dihydroxy-3-oxo-2,3-dihydrospiro[indene-1,9'-xanthene]-5-yl)thioureido)ethyl)hexanamide demonstrated better sensitivity than 5-(2-(4,6-diamino-1,3,5-triazin-2-yl)hydrazinecarbothioamido)-2-(6-hydroxy-3-oxo-3H-xanthen-9-yl)benzoic acid and 3-(4,6-diamino-1,3,5-triazin-2-ylthio)-N-(2-(3-(3',6'-dihydroxy-3-oxo-3H-spiro[isobenzofuran-1,9'-xanthene]-5-yl)thioureido)ethyl)propanamide. The limit of detection (10% inhibition) of the FPIA was 9.3 ng mL(-1) and the IC(50) (50% inhibition) value was 164.7 ng mL(-1). The antibody in the FPIA showed 21.2% cross-reactivity to the fly-killing insecticide cyromazine, but had no cross-reactivity to other natural structurally related compounds. Recoveries, measured in spiked milk and milk powder samples, ranged from 79.4 to 119.0%. Milk samples fortified with melamine were analyzed by this method and confirmed by high-performance liquid chromatography-mass spectrometry. Excellent recoveries and correlation with spiked levels were observed, suggesting that this immunoassay could be applied to the screening of melamine residues in milk and milk powder after a simple dilution procedure.


Assuntos
Laticínios/análise , Contaminação de Alimentos/análise , Imunoensaio/métodos , Triazinas/análise , Animais , Bovinos , Imunoensaio/instrumentação , Leite/química , Pós/análise
14.
Molecules ; 16(8): 7043-57, 2011 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-21849932

RESUMO

A highly specific and sensitive indirect competitive enzyme-linked immunosorbent assay (icELISA)was developed for the first time for the detection of chrysoidine, a dye banned in soybean milk film. Two haptens with different spacer arms were synthesized to produce antibodies. Both homologous and heterologous immunoassay formats were compared to enhance the icELISA sensitivity. The heterologous icELISA exhibited better performance, with an IC(50) (50% inhibitory concentration) of 0.33 ng/mL, a limit of detection (LOD, 10% inhibitory concentration) of 0.04 ng/mL, and a limit of quantitation (LOQ, 20%-80% inhibitory concentration) from 0.09 to 4.9 ng/mL. The developed icELISA was high sensitive and specific, and was applied to determine chrysoidine in fortified soybean milk film samples. The results were in good agreement with that obtained by high-performance liquid chromatography (HPLC) analyses.


Assuntos
Emulsões/análise , Ensaio de Imunoadsorção Enzimática , Contaminação de Alimentos/análise , Glycine max/química , p-Aminoazobenzeno/análogos & derivados , Animais , Anticorpos/imunologia , Ligação Competitiva , Calibragem , Carcinógenos/análise , Cromatografia Líquida de Alta Pressão , Emulsões/química , Poluentes Ambientais/análise , Epitopos , Contaminação de Alimentos/prevenção & controle , Haptenos/química , Haptenos/imunologia , Humanos , Limite de Detecção , Coelhos , p-Aminoazobenzeno/análise
15.
Food Chem ; 353: 128718, 2021 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-33838431

RESUMO

Fraud in the food supply system will be exacerbated by shortages caused by climate change and COVID-19's impact. The dried herbs market exemplifies complex supply chains attractive to criminals seeking financial gain. Real-time remote testing is achievable through development of globally accessible chemometric models for portable near infrared devices, deployed throughout supply chains. This study describes building of models for detection of oregano adulteration, on portable near infrared devices, and comparison to a laboratory-based Fourier-Transform Infrared spectroscopy method. 33/34 portable devices were able to correctly classify 5 out of 6 samples successfully with all adulterated samples being correctly classified following the use of appropriate transferability pre-processing routines. The devices native setup shows limited ability to perform a true screening of oregano using the setup offered. However modifications to the setup could in the future offer a solution that facilitates fit-for-purpose real time detection of adulterated samples within the supply chain.


Assuntos
Contaminação de Alimentos/análise , Origanum/química , Laboratórios , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Espectroscopia de Luz Próxima ao Infravermelho
16.
Foods ; 10(5)2021 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-33925477

RESUMO

The performance of three near-infrared spectroscopy (NIRS) instruments was compared through the investigation of coriander seed authenticity. The Thermo Fisher iS50 NIRS benchtop instrument, the portable Ocean Insights Flame-NIR and the Consumer Physics handheld SCiO device were assessed in conjunction with chemometric modelling in order to determine their predictive capabilities and use as quantitative tools through regression analysis. Two hundred authentic coriander seed samples and ninety adulterated samples were analysed on each device. Prediction models were developed and validated using SIMCA 15 chemometric software. All instruments correctly predicted 100% of the adulterated samples. The best models resulted in correct predictions of 100%, 98.5% and 95.6% for authentic coriander samples using spectra from the iS50, Flame-NIR and SCiO, respectively. The development of regression models highlighted the limitations of the Flame-NIR and SCiO for quantitative analysis, compared to the iS50. However, the results indicate their use as screening tools for on-site analysis of food, at various stages of the food supply chain.

17.
Talanta ; 222: 121533, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33167241

RESUMO

This study assesses the application of a handheld, near infrared spectroscopy (NIRS) device, namely the NeoSpectra Micro, for the determination of oregano authenticity. Utilising a large sample set of oregano (n = 295) and potential adulterants of oregano (n = 109), models were developed and validated using SIMCA 15 software. The models demonstrated excellent predictability for the determination of authentic oregano and adulterant samples. The optimal model resulted in a 93.0% and 97.5% correct prediction for oregano and adulterants, respectively. Different standardisation approaches were assessed to determine model transferability to a second NIRS device. In the case of the second device, the best predictions were achieved with data that had not undergone any spectral standardisation (raw). Subsequently, the optimal model was able to correctly predict 90% of authentic oregano samples and 100% of the adulterant samples on the second device. This study demonstrates the potential of the device to be used as a simple, cost effective, reliable and handheld screening tool for the determination of oregano authenticity, at various stages of the food supply chain. It is believed that such forms of monitoring could be highly beneficial in other areas of food authenticity analysis to help combat the negative economical and health implications of food fraud.


Assuntos
Contaminação de Alimentos , Espectroscopia de Luz Próxima ao Infravermelho , Análise de Alimentos , Cadeia Alimentar , Contaminação de Alimentos/análise
18.
Anal Chem ; 82(7): 2977-88, 2010 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-20232817

RESUMO

A research element of the European Union (EU) sixth Framework project BioCop focused on the development of a surface plasmon resonance (SPR) biosensor assay for the detection of paralytic shellfish poisoning (PSP) toxins in shellfish as an alternative to the increasingly ethically unacceptable mouse bioassay. A biosensor assay was developed using both a saxitoxin binding protein and chip surface in tandem with a highly efficient simple extraction procedure. The present report describes the single laboratory validation of this immunological screening method, for this complex group of toxins with differing toxicities, according to the European Decision 2002/657/EC in conjunction with IUPAC and AOAC single laboratory validation guidelines. The different performance characteristics (detection capability CCbeta, specificity/selectivity, repeatability, reproducibility, stability, and applicability) were determined in relation to the EU regulatory limit of 800 microg of saxitoxin equivalents (STX eq) per kg of shellfish meat. The detection capability CCbeta was calculated to be 120 microg/kg. Intra-assay repeatability was found to be between 2.5 and 12.3% and interassay reproducibility was between 6.1 and 15.2% for different shellfish matrices. Natural samples were also evaluated and the resultant data displayed overall agreements of 96 and 92% with that of the existing AOAC approved methods of mouse bioassay (MBA) and high performance liquid chromatography (HPLC), respectively.


Assuntos
Toxinas Marinhas/química , Ressonância de Plasmônio de Superfície/métodos , Animais , Anticorpos/química , Anticorpos/metabolismo , Bivalves/química , Cardiidae/química , Proteínas de Transporte/química , Toxinas Marinhas/análise , Saxitoxina/análise , Saxitoxina/química , Saxitoxina/imunologia , Intoxicação por Frutos do Mar
19.
Glob Food Sec ; 26: 100447, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33083214

RESUMO

Milk and milk products play a vital role in diets around the globe. Due to their nutritional benefits there has been an increase in production and consumption over the past thirty years. For this growth to continue the safety and authenticity of dairy products needs to be maintained which is a huge area of concern. Throughout the process, from farm to processor, different sources of contamination (biological, chemical or physical) may occur either accidently or intentionally. Through online resources (the EU Rapid Alert System for Food and Feed (RASFF) and HorizonScan) safety and fraud data were collected from the past five years relating to milk and milk products. Cheese notifications were most frequently reported for both safety alerts (pathogenic micro-organisms) and fraud incidences (fraudulent documentation). Alongside the significant number of biological contaminations identified, chemical, physical and inadequate controls (in particular; foreign bodies, allergens, industrial contaminants and mycotoxins) were also found. Although the number of incidents were significantly smaller, these contaminants can still pose a significant risk to human health depending on their toxicity and exposure. Grey literature provided a summary of contamination and fraud issues from around the globe and shows its potential to be used alongside database resources for a holistic overview. In ensuring the integrity of milk during ever changing global factors (climate change, competition between food and feed and global pandemics) it is vital that safety and authenticity issues are continually monitored by industry, researchers and governing bodies.

20.
Foods ; 9(7)2020 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-32708804

RESUMO

The spice paprika (Capsicum annuum and frutescens) is used in a wide variety of cooking methods as well as seasonings and sauces. The oil, paprika oleoresin, is a valuable product; however, once removed from paprika, the remaining spent product can be used to adulterate paprika. Near-infrared (NIR) and Fourier transform infrared (FTIR) were the platforms selected for the development of methods to detect paprika adulteration in conjunction with chemometrics. Orthogonal partial least squares discriminant analysis (OPLS-DA), a supervised technique, was used to develop the chemometric models, and the measurement of fit (R2) and measurement of prediction (Q2) values were 0.853 and 0.819, respectively, for the NIR method and 0.943 and 0.898 respectively for the FTIR method. An external validation set was tested against the model, and a receiver operating curve (ROC) was created. The area under the curve (AUC) for both methods was highly accurate at 0.951 (NIR) and 0.907 (FTIR). The levels of adulteration with 100% correct classification were 50-90% (NIR) and 40-90% (FTIR). Sudan I dye is a commonly used adulterant in paprika; however, in this study it was found that this dye had no effect on the outcome of the result for spent material adulteration.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA