43 research outputs found
Does Pig Density Matter for the Choice of Control Strategies in Classical Swine Fever Epidemic?
This paper examines the importance of pig population density in the area of an outbreak of CSF for the spread of the disease and the choice of control measures. A sector-level market and trade model and a spatial, stochastic, dynamic epidemiological simulation model for the Netherlands were used. Outbreaks in sparsely and densely populated areas were compared under four different control strategies and with two alternative trade assumptions. Results indicate that the control strategy required by current EU legislation is enough to eradicate an epidemic starting in an area with sparse pig population. By contrast, additional control measures are necessary if the outbreak begins in an area with high pig population density. The economic consequences of using preventive slaughter rather than emergency vaccination as an additional control measure depend strongly on the reactions of trading partners. Reducing the number of animal movements significantly reduces the size and length of epidemics in areas with high pig density.Classical Swine Fever epidemics, pig population density, animal transport, emergency vaccination, preventive slaughter, the Netherlands, Livestock Production/Industries,
Strategies to Control Classical Swine Fever: Cost and Risk Perspectives
The paper examines the importance of pig population density in the area of an outbreak of CSF for the spread of the disease and the choice of control measures. A sector-level market and trade model and a spatial, stochastic, dynamic epidemiological simulation model for the Netherlands were used. Outbreaks in sparsely and densely populated areas were compared under four different control strategies and with two alternative trade assumptions. Results indicate that the control strategy required by current EU legislation is enough to eradicate an epidemic starting in an area with sparse pig population. By contrast, additional control measures are necessary if the outbreak begins in an area with high pig population density. The economic consequences of using preventive slaughter rather than emergency vaccination as an additional control measure depend strongly on the reactions of trading partners. Reducing the number of animal movements significantly reduces the size and length of epidemics in areas with high pig density.Classical Swine Fever epidemics, pig population density, animal transport, emergency vaccination, preventive slaughter, the Netherlands, Farm Management,
Consumer-friendly food allergen detection : moving towards smartphone-based immunoassays
In this critical review, we provide a comprehensive overview of immunochemical food allergen assays and detectors in the context of their user-friendliness, through their connection to smartphones. Smartphone-based analysis is centered around citizen science, putting analysis into the hands of the consumer. Food allergies represent a significant worldwide health concern and consumers should be able to analyze their foods, whenever and wherever they are, for allergen presence. Owing to the need for a scientific background, traditional laboratory-based detection methods are generally unsuitable for the consumer. Therefore, it is important to develop simple, safe, and rapid assays that can be linked with smartphones as detectors to improve user accessibility. Smartphones make excellent detection systems because of their cameras, embedded flash functions, portability, connectivity, and affordability. Therefore, this review has summarized traditional laboratory-based methods for food allergen detection such as enzyme-linked-immunosorbent assay, flow cytometry, and surface plasmon resonance, and the potential to modernize these methods by interfacing them with a smartphone readout system, based on the aforementioned smartphone characteristics. This is the first review focusing on smartphone-based food-allergen detection methods designed with the intention of being consumer-friendly. [Figure not available: see fulltext.
Rapid antibody selection using surface plasmon resonance for high-speed and sensitive hazelnut lateral flow prototypes
Lateral Flow Immunoassays (LFIAs) allow for rapid, low-cost, screening of many biomolecules such as food allergens. Despite being classified as rapid tests, many LFIAs take 10–20 min to complete. For a really high-speed LFIA, it is necessary to assess antibody association kinetics. By using a label-free optical technique such as Surface Plasmon Resonance (SPR), it is possible to screen crude monoclonal antibody (mAb) preparations for their association rates against a target. Herein, we describe an SPR-based method for screening and selecting crude anti-hazelnut antibodies based on their relative association rates, cross reactivity and sandwich pairing capabilities, for subsequent application in a rapid ligand binding assay. Thanks to the SPR selection process, only the fast mAb (F-50-6B12) and the slow (S-50-5H9) mAb needed purification for labelling with carbon nanoparticles to exploit high-speed LFIA prototypes. The kinetics observed in SPR were reflected in LFIA, with the test line appearing within 30 s, almost two times faster when F-50-6B12 was used, compared with S-50-5H9. Additionally, the LFIAs have demonstrated their future applicability to real life samples by detecting hazelnut in the sub-ppm range in a cookie matrix. Finally, these LFIAs not only provide a qualitative result when read visually, but also generate semi-quantitative data when exploiting freely downloadable smartphone apps.</p
Direct analysis of lateral flow immunoassays for deoxynivalenol using electrospray ionization mass spectrometry
Lateral flow immunoassays (LFIAs) are widely used for rapid food safety screening analysis. Thanks to simplified protocols and smartphone readouts, LFIAs are expected to be increasingly used on-site, even by non-experts. As a typical follow-up in EU regulatory settings, suspect samples are sent to laboratories for confirmatory analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS). However, re-analysis by LC-MS/MS is laborious and time-consuming. In this work, an identification LFIA (ID-LFIA) approach followed by quadrupole-orbitrap MS or triple quadrupole MS/MS analysis is presented. As a proof of concept, a dedicated ID-LFIA strip was developed for the mycotoxin deoxynivalenol (DON) following its initial screening by a commercial smartphone LFIA. The ID-LFIA strip can be simply immersed in the same sample extract used for the smartphone LFIA screening, and next, DON is retrieved from the monoclonal antibody with a dissociation solution consisting of methanol/ammonia. The solution thus obtained was analyzed directly in MS in order to rapidly confirm the presence of DON and any cross-reacting species. The protocol developed is capable of coping with severe ion suppression caused by LFIA buffers and nitrocellulose substrate residues. Initial analysis of blank, spiked, and incurred samples showed that the newly developed ID-LFIA-MS method was able to confirm the presence or absence of mycotoxins in the samples previously analyzed by LFIA and also differentiate between DON and DON 3-glucoside yielding the positive screening result. The concept and technique developed are envisaged to complement on-site screening and confirmation of any low molecular weight contaminant in future food control frameworks. [Figure not available: see fulltext.]</p
Hand-Held Diode Laser for On-Site Analysis Using Transportable Mass Spectrometry
A hand-held laser diode thermal desorption electrospray ionization (LDTD-ESI) mass spectrometry (MS) method was developed for rapid screening of illegal substances in solid samples. To achieve that, a simple, inexpensive, battery-powered surgical laser diode at 940 nm was employed to ablate the solid samples. The potential of using a black polytetrafluoroethylene substrate to enhance the analytes' desorption to the gas phase was investigated and demonstrated. Among the optimized ESI parameters, the solvent (methanol/water, 50:50, v/v) and the flow rate (50 μL h-1) were critical to obtain the best sensitivity. The applicability was demonstrated for the rapid identification of selective androgen receptor modulators (SARMs) in pills and powders based on accurate mass measurements by time-of-flight MS. Also, the hand-held LDTD-ESI was combined with a transportable single quadrupole MS. The same SARMs samples were analyzed, and identifications were based on in-source cone voltage fragmentation patterns observed. These initial results demonstrate the applicability of the developed simplified LDTD-ESI MS method for future on-site testing of organic compounds in solid samples
Does Pig Density Matter for the Choice of Control Strategies in Classical Swine Fever Epidemic?
This paper examines the importance of pig population density in the area of an outbreak of CSF for the spread of the disease and the choice of control measures. A sector-level market and trade model and a spatial, stochastic, dynamic epidemiological simulation model for the Netherlands were used. Outbreaks in sparsely and densely populated areas were compared under four different control strategies and with two alternative trade assumptions. Results indicate that the control strategy required by current EU legislation is enough to eradicate an epidemic starting in an area with sparse pig population. By contrast, additional control measures are necessary if the outbreak begins in an area with high pig population density. The economic consequences of using preventive slaughter rather than emergency vaccination as an additional control measure depend strongly on the reactions of trading partners. Reducing the number of animal movements significantly reduces the size and length of epidemics in areas with high pig density
Strategies to Control Classical Swine Fever: Cost and Risk Perspectives
The paper examines the importance of pig population density in the area of an outbreak of CSF for the spread of the disease and the choice of control measures. A sector-level market and trade model and a spatial, stochastic, dynamic epidemiological simulation model for the Netherlands were used. Outbreaks in sparsely and densely populated areas were compared
under four different control strategies and with two alternative trade assumptions.
Results indicate that the control strategy required by current EU legislation is enough to eradicate an epidemic starting in an area with sparse pig population. By contrast, additional control measures are necessary if the outbreak begins in an area with high pig population density. The economic consequences of using preventive slaughter rather than emergency vaccination as an additional control measure depend strongly on the reactions of trading partners. Reducing the number of animal movements significantly reduces the size and length of epidemics in areas with high pig density
Microplastics and nanoplastics in food, water, and beverages; part I. occurrence
In recent years, the presence of microplastics (MPs) and nanoplastics (NPs) has been assessed in several environmental matrices, including the marine environment and agricultural soil, suggesting those pollutants are likely to enter the food web. However, there is still a severe lack of information about the occurrence of plastic particles in our food, partially due to the multidimensionality of the data necessary to fully describe MP contamination and the consequent difficulty in validating analytical methods. In this review, consisting of two parts, preliminary results about the presence of MPs in food, water, and beverages are summarized (Part I) and several approaches for the characterization of micro- and nano-sized plastic particles are reported and discussed (Part II). The information gathered in this manuscript highlights the need for a more comprehensive knowledge of MP/NP occurrence along the food chain in order to assess the food safety risk related to those contaminants and implement strategies for their monitoring in products intended for human consumption. Therefore, an outlook of the field towards a coherent, consistent, and policy-relevant data collection and standardization is included in this review
Rapid Single Particle Atmospheric Solids Analysis Probe-Mass Spectrometry for Multimodal Analysis of Microplastics
Despite mass spectrometry (MS) being proven powerful for the characterization of synthetic polymers, its potential for the analysis of single particle microplastics (MPs) is yet to be fully disclosed. To date, MPs are regarded as ubiquitous contaminants, but the limited availability of techniques that enable full characterizations of MPs results in a lack of systematic data regarding their occurrence. In this study, an atmospheric solid analysis probe (ASAP) coupled to a compact quadrupole MS is proposed for the chemical analysis of single particle microplastics, while maintaining full compatibility with complementary staining and image analysis approaches. A two-stage ASAP probe temperature program was optimized for the removal of additives and surface contaminants followed by the actual polymer characterization. The method showed specific mass spectra for a wide range of single particle MPs, including polyolefins, polyaromatics, polyacrylates, (bio)polyesters, polyamides, polycarbonates, and polyacrylonitriles. The single particle size detection limits for polystyrene MPs were found to be 30 and 5 μm in full scan and selected ion recording mode, respectively. Moreover, results are presented of a multimodal microplastic analysis approach in which filtered particles are first characterized by staining and fluorescence microscopy, followed by simple probe picking of individual particles for subsequent analysis by ASAP-MS. The method provides a full characterization of MP contamination, including particle number, particle size, particle shape, and chemical identity. The applicability of the developed multimodal method was successfully demonstrated by the analysis of MPs in bioplastic bottled water