Authentication of pasta is currently determined using molecular biology-based techniques focusing on DNA as the target analyte. Whilst proven to be effective, these approaches can be criticised as being destructive, t...Authentication of pasta is currently determined using molecular biology-based techniques focusing on DNA as the target analyte. Whilst proven to be effective, these approaches can be criticised as being destructive, time consuming, and requiring specialist instrument training. Advances in the field of multispectral imaging (MSI) and hyperspectral imaging (HSI) have facilitated the development of compact imaging platforms with the capability to rapidly differentiate a range of materials (inclusive of grains and seeds) based on surface colour, texture and chemical composition. This preliminary investigation evaluated the applicability of spectral imaging for identification and quantitation of durum wheat grain samples in relation to pasta authenticity. MSI and HSI were capable of rapidly distinguishing between durum wheat and adulterant common wheat cultivars and assigning percentage adulteration levels characterised by low biases and good repeatability estimates. The results demonstrated the potential for spectral imaging based seed/grain adulteration testing to augment existing standard molecular approaches for food authenticity testing.展开更多
Two real-time PCR methods for the relative quantitation of DNA from meat species in food samples are described: these methods are applicable for horse in processed beef meat products, and pork in raw/processed beef me...Two real-time PCR methods for the relative quantitation of DNA from meat species in food samples are described: these methods are applicable for horse in processed beef meat products, and pork in raw/processed beef meat products. Test samples were prepared using raw meat admixtures or processed horse/pork in beef food products made to an industry-standard recipe. The methods were subjected to single laboratory method validation, evaluating the performance characteristics of specificity, PCR efficiency and r-squared (r<sup>2</sup>), Limit of Detection (LOD), Limit of Quantitation (LOQ), and precision and trueness. A limited UK-based inter-laboratory trial of the two methods was completed involving four participating laboratories. Full statistical analysis of the data qualified the applicability of the methods for accurate and sensitive trace-level analysis. The methods were deemed fit for purpose for reproducibly distinguishing between adventitious contamination at 0.1% (w/w), the level for further enforcement action at 1% (w/w), and a level representative of deliberate economically motivated adulteration (10% (w/w)). The data provided evidence that the precision of the two methods was applicable for qualitative and quantitative detection at topically important levels of adulteration. This work has added significant value to the current state of the art in quantitative determination of topical meat species adulteration, allowing analysts to distinguish between adventitious contamination and deliberate adulteration. The resulting methods described in this paper can easily be deployed and used by analytical laboratories for controls and due-diligence testing based on standard laboratory equipment.展开更多
In response to new European Union regulations,studies are underway to mitigate accumulation of toxic cadmium(Cd)in cacao(Theobroma cacao,Tc).This study advances such research with Cd isotope analyses of 19 genetically...In response to new European Union regulations,studies are underway to mitigate accumulation of toxic cadmium(Cd)in cacao(Theobroma cacao,Tc).This study advances such research with Cd isotope analyses of 19 genetically diverse cacao clones and yeast transformed to express cacao natural resistance-associated macrophage protein(NRAMP5)and heavy metal ATPases(HMAs).The plants were enriched in light Cd isotopes relative to the hydroponic solution withΔ^(114/110)Cd_(tot-sol)=−0.22±0.08‰.Leaves show a systematic enrichment of isotopically heavy Cd relative to total plants,in accord with closed-system isotope fractionation ofΔ^(114/110)C_(dseq-mob)=−0.13‰,by sequestering isotopically light Cd in roots/stems and mobilisation of remaining Cd to leaves.The findings demonstrate that(i)transfer of Cd between roots and leaves is primarily unidirectional;(ii)different clones utilise similar pathways for Cd sequestration,which differ from those of other studied plants;(iii)clones differ in their efficiency of Cd sequestration.Transgenic yeast that expresses TcNRAMP5(T.cacao natural resistance-associated macrophage gene)had isotopically lighter Cd than did cacao.This suggests that NRAMP5 transporters constitute an important pathway for uptake of Cd by cacao.Cd isotope signatures of transgenic yeast expressing HMA-family proteins suggest that they may contribute to Cd sequestration.The data are the first to record isotope fractionation induced by transporter proteins in vivo.展开更多
In 2015 a number of cumin spice products were withdrawn from the international market because of the suspected presence of almond, a known allergen from the Prunus genus. However, immunoassay results were unable to pr...In 2015 a number of cumin spice products were withdrawn from the international market because of the suspected presence of almond, a known allergen from the Prunus genus. However, immunoassay results were unable to provide unequivocal evidence of the Prunus species present, because of significant cross-reactivity with other species within the Prunus genus. A novel real-time PCR assay was developed for the specific detection of Prunus mahaleb DNA, a species known to be capable of causing false positives in almond immunoassays. The assay was developed based on available DNA sequence information from the Internal Transcribed Spacer (ITS) region, and tested against representative species within the Prunus genus to ensure no cross-reactivity. Results showed that mahaleb DNA was detected in a cumin spice product subject to the earlier international recalls, which could not be unequivocally identified using immunoassay approaches alone. This short report details preliminary results from the application of this assay, and will be of interest to analytical laboratories involved in trace detection of ingredients in support of relevant food labelling legislation.展开更多
Food allergies represent a clear threat to the general health and wellbeing of those affected which place increasing pressure on food producers and regulatory authorities. Current analytical techniques typically find ...Food allergies represent a clear threat to the general health and wellbeing of those affected which place increasing pressure on food producers and regulatory authorities. Current analytical techniques typically find difficulties distinguishing between closely related Prunus species which include almond (Prunus dulcis), an EU listed allergenic species. This study describes a proof of principle real-time PCR approach utilising DNA melt analyses that targets the internal transcribed spacer (ITS) sequence to differentiate between a panel of Prunus test species. The method was successfully applied to the characterisation of a commercial paprika sample suspected of having being adulterated with almond, referred to the UK Government Chemist in 2015 in its advisory capacity. Subject to further validation work, the method appears to specifically amplify Prunus species and is capable of discrimination based on the resultant melt profiles. The developed method provides analysts with a simple and broad molecular tool to identify common Prunus species for food authenticity and allergen testing purposes. Initial development work demonstrates a promising approach with the potential to improve discrimination between Prunus species not easily resolved by routine analytical methods.展开更多
The present study couples the acid/basis titration and the ICP analysis in order to monitor the concentrations of nitric and hydrofluoric acids, and presents into baths used to pickle alloys of titanium or stainless s...The present study couples the acid/basis titration and the ICP analysis in order to monitor the concentrations of nitric and hydrofluoric acids, and presents into baths used to pickle alloys of titanium or stainless steel, largely employed in the aeronautic industry. The pickling of the alloys releases various metallic cations able to react with HF in order to lead to metal-fluoride complexes and free H+, the last being able to react with the basis. In this study, it was determined: the most significant correlations providing the number of the protons released by the complexation of the metallic cation by the fluoride. The proposed method based on: 1) these correlations;2) the titration pH = f(VKOH) curves;and 3) the content of metallic cations determined by ICP, enables the monitoring of the content of HNO3 and HF into the pickling bath. Assuming that one bath was used for one type of alloy (alloys of Titanium for example, or alloys of stainless steel), then the proposed method appears providing reliable concentration values of both acids as well as metallic cations.展开更多
Organotin(OT)compounds are of continued Arctic concern as they are still widely used despite the most well-studied OT,tributyl tin(TBT),being restricted from use on marine vessels to prevent fouling by marine organism...Organotin(OT)compounds are of continued Arctic concern as they are still widely used despite the most well-studied OT,tributyl tin(TBT),being restricted from use on marine vessels to prevent fouling by marine organisms.The highest OT concentrations found in Arctic fauna are in regions associated with human activity especially shipping.There is an overall trend of declining butyl tin(BT)concentrations in Arctic fauna especially molluscs which are the subject of a limited number of long-term monitoring studies.The incidence of imposex has likewise generally declined in molluscs in response to declining TBT concentrations.There are a number of knowledge gaps in OT occurrence and transport in the Arctic that warrant continued monitoring.OTs,in particular octyl tins,are heavily used in the production of plastic,hence leaching from plastic may be an unrecognized source to Arctic regions.This review also found several studies reporting volatile tin species in the atmosphere suggesting atmospheric transport of volatile tins to the Arctic is possible.Relative to other more well know persistent organic pollutants,there are few reports of OTs in marine mammals and temporal tend studies are needed to define trends in BTs and search for the occurrence of other tin species.展开更多
文摘Authentication of pasta is currently determined using molecular biology-based techniques focusing on DNA as the target analyte. Whilst proven to be effective, these approaches can be criticised as being destructive, time consuming, and requiring specialist instrument training. Advances in the field of multispectral imaging (MSI) and hyperspectral imaging (HSI) have facilitated the development of compact imaging platforms with the capability to rapidly differentiate a range of materials (inclusive of grains and seeds) based on surface colour, texture and chemical composition. This preliminary investigation evaluated the applicability of spectral imaging for identification and quantitation of durum wheat grain samples in relation to pasta authenticity. MSI and HSI were capable of rapidly distinguishing between durum wheat and adulterant common wheat cultivars and assigning percentage adulteration levels characterised by low biases and good repeatability estimates. The results demonstrated the potential for spectral imaging based seed/grain adulteration testing to augment existing standard molecular approaches for food authenticity testing.
文摘Two real-time PCR methods for the relative quantitation of DNA from meat species in food samples are described: these methods are applicable for horse in processed beef meat products, and pork in raw/processed beef meat products. Test samples were prepared using raw meat admixtures or processed horse/pork in beef food products made to an industry-standard recipe. The methods were subjected to single laboratory method validation, evaluating the performance characteristics of specificity, PCR efficiency and r-squared (r<sup>2</sup>), Limit of Detection (LOD), Limit of Quantitation (LOQ), and precision and trueness. A limited UK-based inter-laboratory trial of the two methods was completed involving four participating laboratories. Full statistical analysis of the data qualified the applicability of the methods for accurate and sensitive trace-level analysis. The methods were deemed fit for purpose for reproducibly distinguishing between adventitious contamination at 0.1% (w/w), the level for further enforcement action at 1% (w/w), and a level representative of deliberate economically motivated adulteration (10% (w/w)). The data provided evidence that the precision of the two methods was applicable for qualitative and quantitative detection at topically important levels of adulteration. This work has added significant value to the current state of the art in quantitative determination of topical meat species adulteration, allowing analysts to distinguish between adventitious contamination and deliberate adulteration. The resulting methods described in this paper can easily be deployed and used by analytical laboratories for controls and due-diligence testing based on standard laboratory equipment.
基金supported by grants from the GCRF programmes of STFC(grants ST/P003257/1,4070200262)and UKRI(grant EP/S515875/1)to M.R.as well as funding from Mars Wrigley Confectionery to J.M.D.and M.R.and Cocoa Research UK to J.M.D.V.H.d.O.was supported by CAPES(Coordination for the Improvement of Higher Education Personnel—Brazil)[project:13462-13-0].
文摘In response to new European Union regulations,studies are underway to mitigate accumulation of toxic cadmium(Cd)in cacao(Theobroma cacao,Tc).This study advances such research with Cd isotope analyses of 19 genetically diverse cacao clones and yeast transformed to express cacao natural resistance-associated macrophage protein(NRAMP5)and heavy metal ATPases(HMAs).The plants were enriched in light Cd isotopes relative to the hydroponic solution withΔ^(114/110)Cd_(tot-sol)=−0.22±0.08‰.Leaves show a systematic enrichment of isotopically heavy Cd relative to total plants,in accord with closed-system isotope fractionation ofΔ^(114/110)C_(dseq-mob)=−0.13‰,by sequestering isotopically light Cd in roots/stems and mobilisation of remaining Cd to leaves.The findings demonstrate that(i)transfer of Cd between roots and leaves is primarily unidirectional;(ii)different clones utilise similar pathways for Cd sequestration,which differ from those of other studied plants;(iii)clones differ in their efficiency of Cd sequestration.Transgenic yeast that expresses TcNRAMP5(T.cacao natural resistance-associated macrophage gene)had isotopically lighter Cd than did cacao.This suggests that NRAMP5 transporters constitute an important pathway for uptake of Cd by cacao.Cd isotope signatures of transgenic yeast expressing HMA-family proteins suggest that they may contribute to Cd sequestration.The data are the first to record isotope fractionation induced by transporter proteins in vivo.
文摘In 2015 a number of cumin spice products were withdrawn from the international market because of the suspected presence of almond, a known allergen from the Prunus genus. However, immunoassay results were unable to provide unequivocal evidence of the Prunus species present, because of significant cross-reactivity with other species within the Prunus genus. A novel real-time PCR assay was developed for the specific detection of Prunus mahaleb DNA, a species known to be capable of causing false positives in almond immunoassays. The assay was developed based on available DNA sequence information from the Internal Transcribed Spacer (ITS) region, and tested against representative species within the Prunus genus to ensure no cross-reactivity. Results showed that mahaleb DNA was detected in a cumin spice product subject to the earlier international recalls, which could not be unequivocally identified using immunoassay approaches alone. This short report details preliminary results from the application of this assay, and will be of interest to analytical laboratories involved in trace detection of ingredients in support of relevant food labelling legislation.
文摘Food allergies represent a clear threat to the general health and wellbeing of those affected which place increasing pressure on food producers and regulatory authorities. Current analytical techniques typically find difficulties distinguishing between closely related Prunus species which include almond (Prunus dulcis), an EU listed allergenic species. This study describes a proof of principle real-time PCR approach utilising DNA melt analyses that targets the internal transcribed spacer (ITS) sequence to differentiate between a panel of Prunus test species. The method was successfully applied to the characterisation of a commercial paprika sample suspected of having being adulterated with almond, referred to the UK Government Chemist in 2015 in its advisory capacity. Subject to further validation work, the method appears to specifically amplify Prunus species and is capable of discrimination based on the resultant melt profiles. The developed method provides analysts with a simple and broad molecular tool to identify common Prunus species for food authenticity and allergen testing purposes. Initial development work demonstrates a promising approach with the potential to improve discrimination between Prunus species not easily resolved by routine analytical methods.
文摘The present study couples the acid/basis titration and the ICP analysis in order to monitor the concentrations of nitric and hydrofluoric acids, and presents into baths used to pickle alloys of titanium or stainless steel, largely employed in the aeronautic industry. The pickling of the alloys releases various metallic cations able to react with HF in order to lead to metal-fluoride complexes and free H+, the last being able to react with the basis. In this study, it was determined: the most significant correlations providing the number of the protons released by the complexation of the metallic cation by the fluoride. The proposed method based on: 1) these correlations;2) the titration pH = f(VKOH) curves;and 3) the content of metallic cations determined by ICP, enables the monitoring of the content of HNO3 and HF into the pickling bath. Assuming that one bath was used for one type of alloy (alloys of Titanium for example, or alloys of stainless steel), then the proposed method appears providing reliable concentration values of both acids as well as metallic cations.
文摘Organotin(OT)compounds are of continued Arctic concern as they are still widely used despite the most well-studied OT,tributyl tin(TBT),being restricted from use on marine vessels to prevent fouling by marine organisms.The highest OT concentrations found in Arctic fauna are in regions associated with human activity especially shipping.There is an overall trend of declining butyl tin(BT)concentrations in Arctic fauna especially molluscs which are the subject of a limited number of long-term monitoring studies.The incidence of imposex has likewise generally declined in molluscs in response to declining TBT concentrations.There are a number of knowledge gaps in OT occurrence and transport in the Arctic that warrant continued monitoring.OTs,in particular octyl tins,are heavily used in the production of plastic,hence leaching from plastic may be an unrecognized source to Arctic regions.This review also found several studies reporting volatile tin species in the atmosphere suggesting atmospheric transport of volatile tins to the Arctic is possible.Relative to other more well know persistent organic pollutants,there are few reports of OTs in marine mammals and temporal tend studies are needed to define trends in BTs and search for the occurrence of other tin species.
