Publications by authors named "Susan J MacDonald"

7 Publications

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Analysis of Aflatoxins and Ochratoxin A in Cannabis and Cannabis Products by LC-Fluorescence Detection Using Cleanup with Either Multiantibody Immunoaffinity Columns or an Automated System with In-Line Reusable Immunoaffinity Cartridges.

J AOAC Int 2020 Apr;103(2):494-503

R-Biopharm Rhone Ltd, Block 10, Todd Campus, West of Scotland Science Park, Acre Rd, Glasgow G20 0XA, United Kingdom.

Background: Evidence of fungal contamination of cannabis plants during drying has raised concerns of potential mycotoxin contamination of leaves and flowers and subsequent contamination of derived edible cannabis products. Methods are, therefore, needed for routine monitoring of cannabis to ensure consumer safety consistent with long-standing controls for mycotoxins such as aflatoxins and ochratoxin A (OTA) in foodstuffs.

Objective: To generate preliminary validation data to demonstrate fitness-for-purpose of methods for aflatoxins and OTA in cannabis and cannabis products.

Methods: Extraction of solid matrices with acetonitrile-water (75 + 25) and direct analysis of energy drinks after dilution. Extracts were either passed manually though an immunoaffinity column (IAC) containing antibodies to both aflatoxins and OTA or were analyzed sequentially using an automated system with in-line reusable immunoaffinity cartridges for aflatoxins or OTA. In both cases, analysis was by LC with fluorescence detection.

Results: Recoveries were in the range of 76-120% with relative SDs from 0.8 to 6.6% for aflatoxins and OTA spiked into cannabis dried leaves and flowers, hemp tea, oils, capsules, cookies, chocolate brownies, and an energy drink.

Conclusions: The methods described in this paper are suitable for the cleanup of sample extracts of cannabis and cannabis products.

Highlights: Manual and automated methods with IAC cleanup have been shown to be suitable for routine control of aflatoxins and OTA in cannabis and cannabis products.
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http://dx.doi.org/10.5740/jaoacint.19-0176DOI Listing
April 2020

Alterations in amino acid status in cats with feline dysautonomia.

PLoS One 2017 23;12(3):e0174346. Epub 2017 Mar 23.

Royal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Roslin, Midlothian, United Kingdom.

Feline dysautonomia (FD) is a multiple system neuropathy of unknown aetiology. An apparently identical disease occurs in horses (equine grass sickness, EGS), dogs, rabbits, hares, sheep, alpacas and llamas. Horses with acute EGS have a marked reduction in plasma concentrations of the sulphur amino acids (SAA) cyst(e)ine and methionine, which may reflect exposure to a neurotoxic xenobiotic. The aim of this study was to determine whether FD cats have alterations in amino acid profiles similar to those of EGS horses. Amino acids were quantified in plasma/serum from 14 FD cats, 5 healthy in-contact cats which shared housing and diet with the FD cats, and 6 healthy control cats which were housed separately from FD cats and which received a different diet. The adequacy of amino acids in the cats' diet was assessed by determining the amino acid content of tinned and dry pelleted foods collected immediately after occurrences of FD. Compared with controls, FD cats had increased concentrations of many essential amino acids, with the exception of methionine which was significantly reduced, and reductions in most non-essential amino acids. In-contact cats also had inadequate methionine status. Artefactual loss of cysteine during analysis precluded assessment of the cyst(e)ine status. Food analysis indicated that the low methionine status was unlikely to be attributable to dietary inadequacy of methionine or cystine. Multi-mycotoxin screening identified low concentrations of several mycotoxins in dry food from all 3 premises. While this indicates fungal contamination of the food, none of these mycotoxins appears to induce the specific clinico-pathologic features which characterise FD and equivalent multiple system neuropathies in other species. Instead, we hypothesise that ingestion of another, as yet unidentified, dietary neurotoxic mycotoxin or xenobiotic, may cause both the characteristic disease pathology and the plasma SAA depletion.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0174346PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5363954PMC
August 2017

Fate of Fusarium mycotoxins in maize flour and grits during extrusion cooking.

Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2008 Nov;25(11):1374-84

KAS Mycotoxins, 6 Fern Drive, Taplow, Maidenhead SL60JS, UK.

Extrusion technology is used widely in the manufacture of a range of breakfast cereals and snacks for human consumption and animal feeds. To minimise consumer exposure to mycotoxins, the levels of deoxynivalenol (DON) and zearalenone (ZON) in cereals/cereal products and fumonisins B(1) and B(2) (FB(1) and FB(2)) in maize are controlled by European Union legislation. Relatively few studies, however, have examined the loss of Fusarium mycotoxins during processing. The behaviour of FB(1), FB(2) and fumonisin B(3) (FB(3)), DON and ZON during extrusion of naturally contaminated maize flour and maize grits is examined using pilot-scale equipment. DON and ZON are relatively stable during extrusion cooking but the fumonisins are lost to varying degrees. There is some loss of ZON when present in low concentrations and extruded at higher moisture contents. The presence of additives, such as reducing sugars and sodium chloride, can also affect mycotoxin levels. Moisture content of the cereal feed during extrusion is important and has a greater effect than temperature, particularly on the loss of fumonisins at the lower moistures. The effects are complex and not easy to explain, although more energy input to the extruder is required for drier materials. However, on the basis of these studies, the relationship between the concentration of Fusarium toxins in the raw and finished product is toxin- and process-dependent.
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http://dx.doi.org/10.1080/02652030802136188DOI Listing
November 2008

Fate of the fusarium mycotoxins, deoxynivalenol, nivalenol and zearalenone, during extrusion of wholemeal wheat grain.

Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2008 Mar;25(3):331-7

KAS Mycotoxins, Maidenhead SL6 0JS, UK.

In the European Union, deoxynivalenol in cereals and cereal products is controlled by recent legislation with the objective of minimizing consumer exposure to this mycotoxin. Relatively few studies have examined the loss of Fusarium mycotoxins during processing and whether this is accurately reflected by the processing factors. The behaviour of deoxynivalenol, nivalenol and zearalenone during extrusion of naturally contaminated wholemeal wheat flour has been examined using pilot-scale equipment. Factors examined were temperature and moisture content. Concentrations of the three mycotoxins were little changed by extrusion although the amount of deoxynivalenol decreased at the lowest moisture content. However, this effect did not appear to be temperature-dependent, suggesting that the apparent loss is either due to binding or inability to extract the residue. Under some conditions, concentrations of the mycotoxins, particularly nivalenol, were higher after extrusion.
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http://dx.doi.org/10.1080/02652030701658365DOI Listing
March 2008

Determination of zearalenone in barley, maize and wheat flour, polenta, and maize-based baby food by immunoaffinity column cleanup with liquid chromatography: interlaboratory study.

J AOAC Int 2005 Nov-Dec;88(6):1733-40

Central Science Laboratory, Sand Hutton, York, YO41 1LZ, United Kingdom.

An interlaboratory study was performed on behalf of the UK Food Standards Agency to evaluate the effectiveness of an affinity column cleanup liquid chromatography (LC) method for the determination of zearalenone (ZON) in a variety of cereals and cereal products at proposed European regulatory limits. The test portion is extracted with acetonitrile:water. The sample extract is filtered, diluted, and applied to an affinity column. The column is washed, and ZON is eluted with acetonitrile. ZON is quantified by reversed-phase LC with fluorescence detection. Barley, wheat and maize flours, polenta, and a maize-based baby food naturally contaminated, spiked, and blank (very low level) were sent to 28 collaborators in 9 European countries and 1 collaborator in New Zealand. Participants were asked to spike test portions of all samples at a ZON concentration equivalent to 100 microg/kg. Average recoveries ranged from 91-111%. Based on results for 4 artificially contaminated samples (blind duplicates) and 1 naturally contaminated sample (blind duplicate), the relative standard deviation for repeatability (RSDr) ranged from 6.9-35.8%, and the relative standard deviation for reproducibility (RSDR) ranged from 16.4-38.2%. The method showed acceptable within- and between-laboratory precision for all 5 matrixes, as evidenced by HorRat values <1.7.
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June 2006

Determination of deoxynivalenol in cereals and cereal products by immunoaffinity column cleanup with liquid chromatography: interlaboratory study.

J AOAC Int 2005 Jul-Aug;88(4):1197-204

Central Science Laboratory, Sand Hutton, York, YO41 1LZ, United Kingdom.

An interlaboratory study was performed on behalf of the UK Food Standards Agency to evaluate the effectiveness of an immunoaffinity column cleanup liquid chromatographic (LC) method for the determination of deoxynivalenol in a variety of cereals and cereal products at proposed European regulatory limits. The test portion was extracted with water. The sample extract was filtered a applied to an immunoaffinity column. After being washed with water, the deoxynivalenol was eluted with acetonitrile or methanol. Deoxynivalenol was quantitated by reversed-phase LC with UV determination. Samples of artificially contaminated wheat-flour, rice flour, oat flour, polenta, and wheat based breakfast cereal, naturally contaminated wheat flour, and blank (very low level) samples of each matrix were sent to 13 collaborators in 7 European countries. Participants were asked to spike test portions of all samples at a range of deoxynivalenol concentrations equivalent to 200-2000 ng/g deoxynivalenol. Average recoveries ranged from 78 to 87%. Based on results for 6 artificially contaminated samples (blind duplicates), the relative standard deviation for repeatability (RSDr) ranged from 3.1 to 14.1%, and the relative standard deviation for reproducibility (RSDR) ranged from 11.5 to 26.3%. The method showed acceptable within-laboratory and between-laboratory precision for all 5 matrixes, as evidenced by HorRat values < 1.3.
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October 2005

Determination of ochratoxin A in currants, raisins, sultanas, mixed dried fruit, and dried figs by immunoaffinity column cleanup with liquid chromatography: interlaboratory study.

J AOAC Int 2003 Nov-Dec;86(6):1164-71

Central Science Laboratory, Sand Hutton, York, YO41 1LZ, United Kingdom.

An interlaboratory study was performed on behalf of the Food Standards Agency to evaluate the effectiveness of an affinity column cleanup liquid chromatographic (LC) method for the determination of ochratoxin A in a variety of dried fruit at European regulatory limits. To ensure homogeneity before analysis, laboratory samples are normally slurried with water in the ratio of 5 parts fruit to 4 parts water, and test materials in this form were used in the study. The test portion was extracted with acidified methanol. The extract was filtered, diluted with phosphate-buffered saline, and applied to an affinity column. The column was washed and ochratoxin A was eluted with methanol. Ochratoxin A was quantified by reversed-phase LC. The use of post-column pH shift to enhance the fluorescence of ochratoxin A by the addition of 1.1 M ammonia solution to the column eluant is optional. Determination was by fluorescence. Currants, sultanas, raisins, figs, and mixed fruit (comprising dried pineapple, papaya, sultanas, prunes, dates, and banana chips), both naturally contaminated and blank (very low level), were sent to 24 collaborators in 7 European countries. Participants were asked to spike test portions of all test samples at a level equivalent to 5 ng/g ochratoxin A. Average recoveries ranged from 69 to 74%. Based on results for 5 naturally contaminated test samples (blind duplicates) the relative standard deviation for repeatability (RSDr) ranged from 4.9 to 8.7%, and the relative standard deviation for reproducibility (RSDR) ranged from 14 to 28%. The method showed acceptable within- and between-laboratory precision for all 5 matrixes, as evidenced by HORRAT values <1.3.
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September 2004
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