Physical and immunoaffinity extraction of paralytic shellfish poisoning toxins from cultures of the dinoflagellate Alexandrium tamarense

In the present study the extraction of paralytic shellfish poisoning (PSP) toxins from a toxic strain of the marine dinoflagellate Alexandrium tamarense CCMP-1493 using various mechanical and/or physical procedures was investigated. PBS buffer was investigated as the extraction solvent in order for these procedures to be used directly with immuno-magnetic Ferrospheres-N. The extraction was performed following the determination of when toxin content by the algae was at its highest during batch culture. The methods used for cell lysis and toxin extraction included freeze-thawing, freeze-boiling, steel ball bearing beating, glass bead beating, and sonication. The steel ball bearing beating was determined to release a similar amount of toxin when compared to a modified standard extraction method which was reported to release 100% of toxins from the algal cells and was therefore used in the next phase of the study. This next phase was to determine the feasibility of utilising an antibody coupled to novel magnetic microspheres (Ferrospheres-N) as a simple, rapid immune-capture procedure for PSP toxins extracted from the algae. The effects of increasing mass of Ferrospheres-N on the immuno-capture of the PSP toxins from the toxic algal strain extracts were investigated. Toxin recovery was found to increase when an increasing mass of Ferrospheres-N was used until 96.2% (+/- 1.3 SD) of the toxin extracted from the cells was captured and eluted. Toxin recovery was determined by comparison to an appropriate PSP toxin standard curve following analysis by the AOAC HPLC method. (C) 2011 Elsevier B.V. All rights reserved.

Surface Plasmon Resonance Biosensor Screening Method for Paralytic Shellfish Poisoning Toxins: A Pilot Interlaboratory Study

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 QSPR 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 mu g STXcliHCl equivalents/kg), a high level of saxitoxin (825 mu g STXdiHCl/kg), 2 noncontarninated, and 14 naturally contaminated samples. All 7 participating laboratories completed the study, and HorRat values obtained were

THE IMPACT OF BURNING AND GRAZING OF HEATHLAND PLANTS AND INVERTEBRATES IN COUNTRY ANTRIM

The impact of burning and grazing on plant, ground beetle and spider species was investigated experimentally in stands of varying ages (burnt in 1982 and 1988 and unburnt plots) on an area of heather moorland in County Antrim, north-east Ireland. Burning initiated complex succession pathways which appear to have characteristic plant and invertebrate species associations. Removal of Calluna dominance initiated a period of high plant species diversity. Investigation of initial post-fire regeneration suggested that the frequency of occurrence of plant species changed over time and was affected by grazing. Grouping of species by the position of their renewal bud, i.e. their life-form, did not account for all observed interspecific variation. The dominant species after burning were Eriophorum vaginatum, E. angustifolium and Vaccinium myrtillus. Studies of vegetation canopy structure showed that, even with the exclusion of the main grazing herbivores, Calluna will not re-establish itself as the dominant species until several years after burning. The ground beetle Nebria salina was trapped more often on plots burnt in 1988 than on unburnt plots or those burnt in 1982. In comparison, Pterostichus niger and Carabus granulatus were trapped in greater numbers on plots burnt in 1982 than on unburnt plots and plots burnt in 1988. The large species Carabus problematicus and Carabus glabratus were trapped in greater numbers on unburnt plots. Similarly, more of the spiders Ceratinella brevipes and Centromerita concinna were trapped on the plots burnt in 1982. In comparison, Lepthyphantes zimmermanni and Robertus lividus were trapped more often on unburnt plots than on plots burnt in 1982 and 1988. Results are discussed with respect to the importance of the continuation of traditional heathland management practices.

A quantitative research on S- and SO2-poisoning Pt/Vulcan carbon fuel cell catalyst

A quantitative research on S and SO2 poisoning Pt/Vulcan carbon (Pt/VC) catalysts for fuel cells was conducted by the three-electrode method. Pt/VC electrodes were contaminated by submersion in a SO2- containing solution made up of 0.2 mM Na2SO3 and 0.5 M H2SO4 for different periods of time, and held at 0.05 V (vs. RHE) in 0.5 M H2SO4 solutions in order to gain zero-valence sulfur (S0) poisoned electrodes. The sulfur coverage of Pt was determined from the total charge consumed as the sulfur was oxidized from S0 at 0.05 V (vs. RHE) to sulfate at >1.1 V (vs. RHE). The summation of initial coverage of S0 (S) and coverage of H (H) are approximately equal to 1 (H + S = 1) when 0.5

Food-poisoning and commercial air travel

With the introduction of budget airlines and greater competitiveness amongst all airlines, air travel has now become an extremely popular form of travel, presenting its own unique set of risks from food poisoning. Foodborne illness associated with air travel is quite uncommon in the modern era. However, when it occurs, it may have serious implications for passengers and when crew are affected, has the potential to threaten safety. Quality, safe, in-flight catering relies on high standards of food preparation and storage; this applies at the airport kitchens (or at subcontractors' facilities), on the aircraft and in the transportation vehicles which carry the food from the ground source to the aircraft. This is especially challenging in certain countries. Several foodborne outbreaks have been recorded by the airline industry as a result of a number of different failures of these systems. These have provided an opportunity to learn from past mistakes and current practice has, therefore, reached such a standard so as to minimise risk of failures of this kind. This review examines: (i) the origin of food safety in modern commercial aviation; (ii) outbreaks which have occurred previously relating to aviation travel; (iii) the microbiological quality of food and water on board commercial aircraft; and (iv) how Hazard Analysis Critical Control Points may be employed to maintain food safety in aviation travel.

Emergency slaughter of casualty cattle increases the prevalence of anthelmintic drug residues in muscle

The ProSafeBeef project studied the prevalence of residues of anthelmintic drugs used to control parasitic worms and fluke in beef cattle in Ireland. Injured (casualty) cattle may enter the human food chain under certain conditions, verified by an attending veterinarian and the livestock keeper. An analytical survey was conducted to determine if muscle from casualty cattle contained a higher prevalence of anthelmintic drug residues than healthy (full slaughter weight) cattle as a result of possible non-observance of complete drug withdrawal periods. A validated analytical method based on matrix solid-phase dispersive extraction (QuEChERS) and ultra-performance liquid chromatography-tandem mass spectrometry was used to quantify 37 anthelmintic drugs and metabolites in muscle (assay decision limits, CCa, 0.15-10.2 µg kg -1). Of 199 control samples of beef purchased in Irish shops, 7% contained detectable anthelmintic drug residues but all were compliant with European Union Maximum Residue Limits (MRL). Of 305 muscle samples from injured cattle submitted to abattoirs in Northern Ireland, 17% contained detectable residues and 2% were non-compliant (containing either residues at concentrations above the MRL or residues of a compound unlicensed for use in cattle). Closantel and ivermectin were the most common residues, but a wider range of drugs was detected in muscle of casualty cattle than in retail beef. These data suggest that specific targeting of casualty cattle for testing for anthelmintic residues may be warranted in a manner similar to the targeted testing for antimicrobial compounds often applied in European National Residues Surveillance Schemes. © 2012 Copyright Taylor and Francis Group, LLC.

Stability during cooking of anthelmintic veterinary drug residues in beef

Anthelmintic drugs are widely used for treatment of parasitic worms in livestock, but little is known about the stability of their residues in food under conventional cooking conditions. As part of the European Commissionfunded research project ProSafeBeef, cattle were medicated with commercially available anthelmintic preparations, comprising 11 active ingredients (corresponding to 21 marker residues). Incurred meat and liver were cooked by roasting (40 min at 190°C) or shallow frying (muscle 8-12 min, liver 14-19 min) in a domestic kitchen. Raw and cooked tissues and expressed juices were analysed using a novel multi-residue dispersive solid-phase extraction method (QuEChERS) coupled with ultra-performance liquid chromatography-tandem mass spectrometry. After correction for sample weight changes during cooking, no major losses were observed for residues of oxyclozanide, clorsulon, closantel, ivermectin, albendazole, mebendazole or fenbendazole. However, significant losses were observed for nitroxynil (78% in fried muscle, 96% in roast muscle), levamisole (11% in fried muscle, 42% in fried liver), rafoxanide (17% in fried muscle, 18% in roast muscle) and triclabendazole (23% in fried liver, 47% in roast muscle). Migration of residues from muscle into expressed cooking juices varied between drugs, constituting 0% to 17% (levamisole) of total residues remaining after cooking. With the exception of nitroxynil, residues of anthelmintic drugs were generally resistant to degradation during roasting and shallow frying. Conventional cooking cannot, therefore, be considered a safeguard against ingestion of residues of anthelmintic veterinary drugs in beef. © 2011 Taylor & Francis.

Uptake and translocation of inorganic and methylated arsenic species by plants

The uptake and translocation into shoots of arsenate, methylarsonate (MA), and dimethylarsinate (DMA) by 46 different plant species were studied. The plants (n = 3 per As species) were exposed for 24 h to 1 mg of As per litre under identical conditions. Total arsenic was measured in the roots and the shoots by acid digestion and inductively coupled plasma mass spectrometry from which, besides total As values, root absorption factors and shoot-to-root transfer factors were calculated. As uptake into the root for the different plant species ranged from 1.2 to 95 (mu g of As per g of dry weight) for As-V, from 0.9 to 44 for MA(V) and from 0.8 to 13 for DMA(V), whereas in shoots the As concentration ranged from 0.10 to 17 for As-V, 0.1 to 13 for MA(V), and 0.2 to 17 for DMA(V). The mean root absorption factor for As-V (1.2 to 95%) was five times higher than for DMA(V) (0.8 to 13%) and 2.5 times higher than for MA(V) (0.9 to 44%). Although the uptake of arsenic in the form of As-V was significantly higher than that of MA(V) and DMA(V), the translocation of the methylated species was more efficient in most plant species studied. Thus, an exposure of plants to DMA(V) or MA(V) can result in higher arsenic concentrations in the shoots than when exposed to As-V. Shoot-to-root transfer factors (TFs) for all plants varied with plant and arsenic species. While As-V had a median TF of 0.09, the TF of DMA(V) was nearly a factor of 10 higher (0.81). The median TF for MA(V) was in between (0.30). Although the TF for MA(V) correlates well with the TF for DMA(V), the plants can be separated into two groups according to their TF of DMA(V) in relation to their TF of As-V. One group can immobilise DMA(V) in the roots, while the other group translocates DMA(V) very efficiently into the shoot. The reason for this is as yet unknown.