It is obvious that food and feed should be safe and wholesome in order to protect the consumer and to ensure animal health and welfare. Animal health and welfare are important factors that con- tribute to the maintena...It is obvious that food and feed should be safe and wholesome in order to protect the consumer and to ensure animal health and welfare. Animal health and welfare are important factors that con- tribute to the maintenance of food quality and safety. All stakeholders require a risk-based, proportionate, integrated and transparent approach to ＇farm to fork＇ official control across all EU member states and between major world trading partners. Also consumers and industry require a consistent EU and global approach to food law implementation and enforcement to prevent differences in food safety and trading conditions developing. To monitor compliance with feed and food law samples have to be analysed by laboratories in EU member states and in other countries who export into the EU. Many analytical methods applied for such official controls are complex. This is particularly the case for methods used for the detection of approved and unapproved additives, veterinary and pesticide residues and natural and process contaminants. How do we ensure consistency and comparability of analytical measurements between laboratories and between countries？ How do we predict and anticipate the target analytes that we may have to detect and determine in samples from the food chain next week, next month, and next year？ As a consequence, how do we prepare analytical methods that will be capable of addressing these challenges and how do we demonstrate that they are robust, validated and provide data that will withstand challenge？ These are problems that are faced by laboratories in all trading nations. This article will review the issues, describe a project that aims to anticipate problems that may affect the food chain in the future and review approaches that enable laboratories to demonstrate the reliability of their methods of analysis via the use of validation protocols, reference ma- terials and proficiency testing schemes.展开更多
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
The hydration of cement compounds gives hydrated compounds, which allow linking together, the different particles and aggregate of cement, and gives the concrete the required qualities. The dynamics of hydration react...The hydration of cement compounds gives hydrated compounds, which allow linking together, the different particles and aggregate of cement, and gives the concrete the required qualities. The dynamics of hydration reactions will depend on many factors, such as the fineness of cement, the ratio w/c during hydration, temperature, mixing technique, and the presence of additives in blended cement, as pozzolan, tuff and slag from blast furnaces. We studied the thermal and kinetic reactions of Portland cement hydration, and its variants with different additions using a differential scanning calorimetric analysis. The parameters from these models of curves allow us to evaluate the enthalpies, and the degree of progression of this blended cement, and finally determine their activation energies. We can say that the hydration of Portland cement is due to a series of reactions as （ C3S,C2S,C3A and C4AF reactions with water） and each of them, has its own kinetic, the experimental measurement of the heat of hydration, allows us to represent the overall kinetics of these reactions values of activation energy, they are therefore apparent and global energy. In our experiments, significant differences in these physicochemical parameters were observed, depending on the additive used.展开更多
Structural analogues of bicyclic peroxides belonging to the G factors family have been synthesised under Mannieh type conditions, followed by an autoxidation step furnishing exclusively the peroxide. As electron trans...Structural analogues of bicyclic peroxides belonging to the G factors family have been synthesised under Mannieh type conditions, followed by an autoxidation step furnishing exclusively the peroxide. As electron transfer from heine or free iron to peroxide is the first step in the mode of action ofartemisinin -like compound, Fe（fl） induced reduction was studied and the reactivity of the intermediate C-centered radical formed was correlated to the antimalarial activity. Dissociative electron transfer was studied by electrochemistry and allowed the evaluation of the standard reduction potentials and other pertinent thermochemical information. These bicyclic peroxides were evaluated in vitro against Plasmodium falciparum and revealed moderate to good activity.展开更多
In recent years,cold-formed steel(CFS)built-up sections have gained a lot of attention in construction.This is mainly because of their structural efficiency and the design advantages they offer.They provide better loa...In recent years,cold-formed steel(CFS)built-up sections have gained a lot of attention in construction.This is mainly because of their structural efficiency and the design advantages they offer.They provide better loadbearing strength and show greater resistance to elastic instability.This study looks at both experimental and numerical analysis of built-up CFS columns.The columns were formed by joining two C-sections in different ways:back-to-back,face-to-face,and box arrangements.Each type was tested with different slenderness ratios.For the experiments,the back-to-back and box sections were connected using two rows of rivets.The face-to-face sections,on the other hand,were joined by welding.In order to improve axial strength and overall stability,all column samples were filled with ordinary concrete,conforming to class C25/30.The numerical modeling was done in ABAQUS to study themechanical behavior of the columns.This helped in understanding how different joining methods affect their axial compression performance.Analytical checkswere also carried out using Eurocode 3 for hollowsections and Eurocode 4 for concretefilled sections.The role of concrete confinement was examined as well,following American Concrete Institute(ACI)guidelines,for both face-to-face and box-shaped columns.Thenumerical results matched closely with the experimental findings,with variations of less than 5%.The study identified key failure modes such as local buckling and distortional buckling.It highlighted how section shape,type of connection,and concrete infill all play amajor role in improving the strength of built-up CFS columns.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It is obvious that food and feed should be safe and wholesome in order to protect the consumer and to ensure animal health and welfare. Animal health and welfare are important factors that con- tribute to the maintenance of food quality and safety. All stakeholders require a risk-based, proportionate, integrated and transparent approach to ＇farm to fork＇ official control across all EU member states and between major world trading partners. Also consumers and industry require a consistent EU and global approach to food law implementation and enforcement to prevent differences in food safety and trading conditions developing. To monitor compliance with feed and food law samples have to be analysed by laboratories in EU member states and in other countries who export into the EU. Many analytical methods applied for such official controls are complex. This is particularly the case for methods used for the detection of approved and unapproved additives, veterinary and pesticide residues and natural and process contaminants. How do we ensure consistency and comparability of analytical measurements between laboratories and between countries？ How do we predict and anticipate the target analytes that we may have to detect and determine in samples from the food chain next week, next month, and next year？ As a consequence, how do we prepare analytical methods that will be capable of addressing these challenges and how do we demonstrate that they are robust, validated and provide data that will withstand challenge？ These are problems that are faced by laboratories in all trading nations. This article will review the issues, describe a project that aims to anticipate problems that may affect the food chain in the future and review approaches that enable laboratories to demonstrate the reliability of their methods of analysis via the use of validation protocols, reference ma- terials and proficiency testing schemes.
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The hydration of cement compounds gives hydrated compounds, which allow linking together, the different particles and aggregate of cement, and gives the concrete the required qualities. The dynamics of hydration reactions will depend on many factors, such as the fineness of cement, the ratio w/c during hydration, temperature, mixing technique, and the presence of additives in blended cement, as pozzolan, tuff and slag from blast furnaces. We studied the thermal and kinetic reactions of Portland cement hydration, and its variants with different additions using a differential scanning calorimetric analysis. The parameters from these models of curves allow us to evaluate the enthalpies, and the degree of progression of this blended cement, and finally determine their activation energies. We can say that the hydration of Portland cement is due to a series of reactions as （ C3S,C2S,C3A and C4AF reactions with water） and each of them, has its own kinetic, the experimental measurement of the heat of hydration, allows us to represent the overall kinetics of these reactions values of activation energy, they are therefore apparent and global energy. In our experiments, significant differences in these physicochemical parameters were observed, depending on the additive used.
文摘Structural analogues of bicyclic peroxides belonging to the G factors family have been synthesised under Mannieh type conditions, followed by an autoxidation step furnishing exclusively the peroxide. As electron transfer from heine or free iron to peroxide is the first step in the mode of action ofartemisinin -like compound, Fe（fl） induced reduction was studied and the reactivity of the intermediate C-centered radical formed was correlated to the antimalarial activity. Dissociative electron transfer was studied by electrochemistry and allowed the evaluation of the standard reduction potentials and other pertinent thermochemical information. These bicyclic peroxides were evaluated in vitro against Plasmodium falciparum and revealed moderate to good activity.
文摘In recent years,cold-formed steel(CFS)built-up sections have gained a lot of attention in construction.This is mainly because of their structural efficiency and the design advantages they offer.They provide better loadbearing strength and show greater resistance to elastic instability.This study looks at both experimental and numerical analysis of built-up CFS columns.The columns were formed by joining two C-sections in different ways:back-to-back,face-to-face,and box arrangements.Each type was tested with different slenderness ratios.For the experiments,the back-to-back and box sections were connected using two rows of rivets.The face-to-face sections,on the other hand,were joined by welding.In order to improve axial strength and overall stability,all column samples were filled with ordinary concrete,conforming to class C25/30.The numerical modeling was done in ABAQUS to study themechanical behavior of the columns.This helped in understanding how different joining methods affect their axial compression performance.Analytical checkswere also carried out using Eurocode 3 for hollowsections and Eurocode 4 for concretefilled sections.The role of concrete confinement was examined as well,following American Concrete Institute(ACI)guidelines,for both face-to-face and box-shaped columns.Thenumerical results matched closely with the experimental findings,with variations of less than 5%.The study identified key failure modes such as local buckling and distortional buckling.It highlighted how section shape,type of connection,and concrete infill all play amajor role in improving the strength of built-up CFS columns.
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.
