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G. S. Shephard
Cape Peninsula University of Technology, Institute of Biomedical and Microbial Biotechnology, Cape Town, South Africa (retired)

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Journal article
Published: 12 April 2021 in World Mycotoxin Journal
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ACS Style

Gordon S. Shephard. Professor Wentzel C.A. Gelderblom (1951-2021). World Mycotoxin Journal 2021, 14, 237 -237.

AMA Style

Gordon S. Shephard. Professor Wentzel C.A. Gelderblom (1951-2021). World Mycotoxin Journal. 2021; 14 (2):237-237.

Chicago/Turabian Style

Gordon S. Shephard. 2021. "Professor Wentzel C.A. Gelderblom (1951-2021)." World Mycotoxin Journal 14, no. 2: 237-237.

Journal article
Published: 05 November 2020 in Food Control
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Fumonisin esterase FumD (EC 3.1.1.87), FUMzyme® (BIOMIN, Austria), effectively detoxifies fumonisin B mycotoxins (FB) by hydrolysis and removal of the tricarballylic acid groups. The current study evaluated FumD detoxification of total FB (FBT) in commercial maize utilising an experimental dry milling plant by introducing the enzyme during the kernel conditioning stage. Total FB and the hydrolysed product of FB1, HFB1, in maize and milling products were determined by LC-MS/MS. During maize conditioning of 4 h 10 min substantial FB1 hydrolysis was achieved between 1 and 4 U FumD/100 g maize. Complete conversion into HFB1 was delayed and only achieved at the highest enzyme concentration (32 U/100 g maize) reaching a 1:1 M conversion ratio. Dry milling of maize containing 3.29 ± 0.20 μmole FBT/kg (2354 ± 140 μg/kg) in the absence of FumD, resulted in a 2.5-fold increase in the FBT concentration in total hominy feed (8.34 ± 0.22 μmol/kg) (5979 ± 158 μg/kg) compared to the levels that prevail in Super (0.52 ± 0.07 μmol/kg) (347 ± 48 μg/kg) and Special (1.70 ± 0.01 μmol/kg) (1213 ± 8 μg/kg) maize meal, and Semolina (1.07 ± 0.14 μmol/kg) (765 ± 100 μg/kg) milling products. Introduction of FumD (40 U/kg) mainly impacted the total hominy feed product (germ + hominy milling fractions), constituting up to 30% of the reconstituted whole maize. A 99% reduction in FBT was obtained in total hominy feed, 48% in Semolina, 7% in Special maize meal, whereas no reduction was recorded in Super maize meal. FB1 reduction rates depend on the contamination level, kernel moisture and the diffusion rate from inner kernel layers to the kernel surface/aqueous interface. Risk modelling in children and adults indicated that FumD-treated whole maize and the resultant Semolina milling product intended for human consumption reduces the risk of exposure to FBT. However, no reduction in the exposure risk was observed when considering the Super and Special maize meal milling products. FB reduction in total hominy feed could open up new applications, such as its dietary incorporation as a source of fibre, minerals and bioactive plant constituents in maize-based food. In addition, the animal feed industry and subsistence maize farming communities using rudimentary milling processes, could also benefit.

ACS Style

Johanna F. Alberts; Ibtisaam Davids; Wulf-Dieter Moll; Gerd Schatzmayr; Hester-Mari Burger; Gordon S. Shephard; Wentzel C.A. Gelderblom. Enzymatic detoxification of the fumonisin mycotoxins during dry milling of maize. Food Control 2020, 123, 107726 .

AMA Style

Johanna F. Alberts, Ibtisaam Davids, Wulf-Dieter Moll, Gerd Schatzmayr, Hester-Mari Burger, Gordon S. Shephard, Wentzel C.A. Gelderblom. Enzymatic detoxification of the fumonisin mycotoxins during dry milling of maize. Food Control. 2020; 123 ():107726.

Chicago/Turabian Style

Johanna F. Alberts; Ibtisaam Davids; Wulf-Dieter Moll; Gerd Schatzmayr; Hester-Mari Burger; Gordon S. Shephard; Wentzel C.A. Gelderblom. 2020. "Enzymatic detoxification of the fumonisin mycotoxins during dry milling of maize." Food Control 123, no. : 107726.

Journal article
Published: 10 September 2019 in Toxins
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Enzymatic detoxification has become a promising approach for control of mycotoxins postharvest in grains through modification of chemical structures determining their toxicity. In the present study fumonisin esterase FumD (EC 3.1.1.87) (FUMzyme®; BIOMIN, Tulln, Austria), hydrolysing fumonisin (FB) mycotoxins by de-esterification, was utilised to develop an enzymatic reduction method in a maize kernel enzyme incubation mixture. Efficacy of the FumD FB reduction method in "low" and "high" FB contaminated home-grown maize was compared by monitoring FB1 hydrolysis to the hydrolysed FB1 (HFB1) product utilising a validated LC-MS/MS analytical method. The method was further evaluated in terms of enzyme activity and treatment duration by assessing enzyme kinetic parameters and the relative distribution of HFB1 between maize kernels and the residual aqueous environment. FumD treatments resulted in significant reduction (≥80%) in "low" (≥1000 U/L, p < 0.05) and "high" (100 U/L, p < 0.05; ≥1000 U/L, p < 0.0001) FB contaminated maize after 1 h respectively, with an approximate 1:1 µmol conversion ratio of FB1 into the formation of HFB1. Enzyme kinetic parameters indicated that, depending on the activity of FumD utilised, a significantly (p < 0.05) higher FB1 conversion rate was noticed in "high" FB contaminated maize. The FumD FB reduction method in maize could find application in commercial maize-based practices as well as in communities utilising home-grown maize as a main dietary staple and known to be exposed above the tolerable daily intake levels.

ACS Style

Johanna Alberts; Gerd Schatzmayr; Wulf-Dieter Moll; Ibtisaam Davids; John Rheeder; Hester-Mari Burger; Gordon Shephard; Wentzel Gelderblom. Detoxification of the Fumonisin Mycotoxins in Maize: An Enzymatic Approach. Toxins 2019, 11, 523 .

AMA Style

Johanna Alberts, Gerd Schatzmayr, Wulf-Dieter Moll, Ibtisaam Davids, John Rheeder, Hester-Mari Burger, Gordon Shephard, Wentzel Gelderblom. Detoxification of the Fumonisin Mycotoxins in Maize: An Enzymatic Approach. Toxins. 2019; 11 (9):523.

Chicago/Turabian Style

Johanna Alberts; Gerd Schatzmayr; Wulf-Dieter Moll; Ibtisaam Davids; John Rheeder; Hester-Mari Burger; Gordon Shephard; Wentzel Gelderblom. 2019. "Detoxification of the Fumonisin Mycotoxins in Maize: An Enzymatic Approach." Toxins 11, no. 9: 523.

Review
Published: 12 June 2019 in Toxins
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Maize is a staple crop in rural subsistence regions of southern Africa, is mainly produced for direct household consumption and is often contaminated with high levels of mycotoxins. Chronic exposure to mycotoxins is a risk factor for human diseases as it is implicated in the development of cancer, neural tube defects as well as stunting in children. Although authorities may set maximum levels, these regulations are not effective in subsistence farming communities. As maize is consumed in large quantities, exposure to mycotoxins will surpass safe levels even where the contamination levels are below the regulated maximum levels. It is clear that the lowering of exposure in these communities requires an integrated approach. Detailed understanding of agricultural practices, mycotoxin occurrence, climate change/weather patterns, human exposure and risk are warranted to guide adequate intervention programmes. Risk communication and creating awareness in affected communities are also critical. A range of biologically based products for control of mycotoxigenic fungi and mycotoxins in maize have been developed and commercialised. Application of these methods is limited due to a lack of infrastructure and resources. Other challenges regarding integration and sustainability of technological and community-based mycotoxin reduction strategies include (i) food security, and (ii) the traditional use of mouldy maize.

ACS Style

Johanna Alberts; John Rheeder; Wentzel Gelderblom; Gordon Shephard; Hester-Mari Burger. Rural Subsistence Maize Farming in South Africa: Risk Assessment and Intervention models for Reduction of Exposure to Fumonisin Mycotoxins. Toxins 2019, 11, 334 .

AMA Style

Johanna Alberts, John Rheeder, Wentzel Gelderblom, Gordon Shephard, Hester-Mari Burger. Rural Subsistence Maize Farming in South Africa: Risk Assessment and Intervention models for Reduction of Exposure to Fumonisin Mycotoxins. Toxins. 2019; 11 (6):334.

Chicago/Turabian Style

Johanna Alberts; John Rheeder; Wentzel Gelderblom; Gordon Shephard; Hester-Mari Burger. 2019. "Rural Subsistence Maize Farming in South Africa: Risk Assessment and Intervention models for Reduction of Exposure to Fumonisin Mycotoxins." Toxins 11, no. 6: 334.

Short communication
Published: 20 February 2019 in International Journal of Food Microbiology
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Maize (Zea mays), sorghum (Sorghum bicolor) and pearl millet (Pennisetum glaucum) are basic staple foods for many rural or poorer communities. These crops are susceptible to plant diseases caused by multiple species of Fusarium, some of which also produce mycotoxins, including fumonisins and moniliformin that are detrimental to both humans and domesticated animals. Eighteen potentially toxigenic Fusarium strains were isolated from maize (n = 10), sorghum (n = 7) and pearl millet (n = 1) growing in the same field in Nigeria. The 17 strains from maize and sorghum were all F. proliferatum and the one strain from pearl millet was F. pseudonygamai. Under conducive conditions, the 17 F. proliferatum strains produced fumonisins, 11 in relatively large quantities (700–17,000 mg total fumonisins, i.e., FB1 + FB2 + FB3/kg culture material), and six at 100 mg of moniliformin per kg culture material with a maximum of 8900 mg/kg culture material. All strains could use all grains for growth and toxin production, regardless of the host from which they were isolated. Isolates varied in the amount of toxin produced on each substrate, with toxin production a property of the strain and not the host from which the strain was recovered. However, the extent to which a toxin-producing phenotype could be altered by the grain on which the fungus was grown is consistent with subtle genetic × environment interactions that require a larger data set than the one presented here to rigorously identify. In conclusion, there is significant variation in the ability of strains of F. proliferatum to produce fumonisins and moniliformin on maize, sorghum and millet. If the amount of toxin produced on the various grains in this study reflects real-world settings, e.g., poor storage, then the consumers of these contaminated grains could be exposed to mycotoxin levels that greatly exceed the tolerable daily intakes.

ACS Style

Hester F. Vismer; Gordon S. Shephard; Liana van der Westhuizen; Pamella Mngqawa; Vuyiswa Bushula-Njah; John F. Leslie. Mycotoxins produced by Fusarium proliferatum and F. pseudonygamai on maize, sorghum and pearl millet grains in vitro. International Journal of Food Microbiology 2019, 296, 31 -36.

AMA Style

Hester F. Vismer, Gordon S. Shephard, Liana van der Westhuizen, Pamella Mngqawa, Vuyiswa Bushula-Njah, John F. Leslie. Mycotoxins produced by Fusarium proliferatum and F. pseudonygamai on maize, sorghum and pearl millet grains in vitro. International Journal of Food Microbiology. 2019; 296 ():31-36.

Chicago/Turabian Style

Hester F. Vismer; Gordon S. Shephard; Liana van der Westhuizen; Pamella Mngqawa; Vuyiswa Bushula-Njah; John F. Leslie. 2019. "Mycotoxins produced by Fusarium proliferatum and F. pseudonygamai on maize, sorghum and pearl millet grains in vitro." International Journal of Food Microbiology 296, no. : 31-36.

Short communication
Published: 06 October 2018 in Food Control
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The fumonisins are carcinogenic mycotoxins that have been implicated in various adverse human health effects. Recently, the Codex Alimentarius Commission set maximum levels (MLs) for fumonisin mycotoxins at 4000 µg/kg for raw maize and 2000 µg/kg for maize flour and maize meal and these have been incorporated into South African health regulations. The MLs are intended to be health protective such that fumonisin exposures will be below the provisional maximum tolerable daily intake (PMTDI) of fumonisin of 2 µg/kg body weight/day set by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). South Africa has an extensive commercial maize farming industry as well as a large subsistence farming population reliant on home-grown maize. The available data on fumonisin contamination levels indicates that these MLs are readily met by the commercial crop. However, the situation in subsistence farming areas such as in the Eastern Cape Province region is of concern. The daily consumption of large amounts of highly fumonisin-contaminated home-grown maize is of relevance mainly due to rudimentary milling, which is not subject to the reduction in mycotoxin contamination associated with commercial milling. Analysis of historical fumonisin data from the Eastern Cape region indicates that approximately 12.8% of raw maize and 25% of the rural locally produced flour would not meet the respective MLs of 4000 µg/kg ML and 2000 µg/kg. Further analysis shows that given the high maize intake levels of this population, only prohibitively low MLs for raw maize of around 100 to 300 µg/kg would be health protective for different age groups in this area. Based on this analysis, the lowering of fumonisin exposure in subsistence farmers requires an integrated approach and cannot be achieved purely by regulatory means.

ACS Style

Gordon S. Shephard; Hester-Mari Burger; John P. Rheeder; Johanna F. Alberts; Wentzel C.A. Gelderblom. The effectiveness of regulatory maximum levels for fumonisin mycotoxins in commercial and subsistence maize crops in South Africa. Food Control 2018, 97, 77 -80.

AMA Style

Gordon S. Shephard, Hester-Mari Burger, John P. Rheeder, Johanna F. Alberts, Wentzel C.A. Gelderblom. The effectiveness of regulatory maximum levels for fumonisin mycotoxins in commercial and subsistence maize crops in South Africa. Food Control. 2018; 97 ():77-80.

Chicago/Turabian Style

Gordon S. Shephard; Hester-Mari Burger; John P. Rheeder; Johanna F. Alberts; Wentzel C.A. Gelderblom. 2018. "The effectiveness of regulatory maximum levels for fumonisin mycotoxins in commercial and subsistence maize crops in South Africa." Food Control 97, no. : 77-80.

Opinion
Published: 04 April 2018 in Toxins
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Mycotoxins are major food contaminants affecting global food security, especially in low and middle-income countries. The European Union (EU) funded project, MycoKey, focuses on “Integrated and innovative key actions for mycotoxin management in the food and feed chains” and the right to safe food through mycotoxin management strategies and regulation, which are fundamental to minimizing the unequal access to safe and sufficient food worldwide. As part of the MycoKey project, a Mycotoxin Charter (charter.mycokey.eu) was launched to share the need for global harmonization of mycotoxin legislation and policies and to minimize human and animal exposure worldwide, with particular attention to less developed countries that lack effective legislation. This document is in response to a demand that has built through previous European Framework Projects—MycoGlobe and MycoRed—in the previous decade to control and reduce mycotoxin contamination worldwide. All suppliers, participants and beneficiaries of the food supply chain, for example, farmers, consumers, stakeholders, researchers, members of civil society and government and so forth, are invited to sign this charter and to support this initiative.

ACS Style

Antonio F. Logrieco; J. David Miller; Mari Eskola; Rudolf Krska; Amare Ayalew; Ranajit Bandyopadhyay; Paola Battilani; Deepak Bhatnagar; Sofia Chulze; Sarah De Saeger; Peiwu Li; Giancarlo Perrone; Amnart Poapolathep; Endang S. Rahayu; Gordon S. Shephard; François Stepman; Hao Zhang; John F. Leslie. The Mycotox Charter: Increasing Awareness of, and Concerted Action for, Minimizing Mycotoxin Exposure Worldwide. Toxins 2018, 10, 149 .

AMA Style

Antonio F. Logrieco, J. David Miller, Mari Eskola, Rudolf Krska, Amare Ayalew, Ranajit Bandyopadhyay, Paola Battilani, Deepak Bhatnagar, Sofia Chulze, Sarah De Saeger, Peiwu Li, Giancarlo Perrone, Amnart Poapolathep, Endang S. Rahayu, Gordon S. Shephard, François Stepman, Hao Zhang, John F. Leslie. The Mycotox Charter: Increasing Awareness of, and Concerted Action for, Minimizing Mycotoxin Exposure Worldwide. Toxins. 2018; 10 (4):149.

Chicago/Turabian Style

Antonio F. Logrieco; J. David Miller; Mari Eskola; Rudolf Krska; Amare Ayalew; Ranajit Bandyopadhyay; Paola Battilani; Deepak Bhatnagar; Sofia Chulze; Sarah De Saeger; Peiwu Li; Giancarlo Perrone; Amnart Poapolathep; Endang S. Rahayu; Gordon S. Shephard; François Stepman; Hao Zhang; John F. Leslie. 2018. "The Mycotox Charter: Increasing Awareness of, and Concerted Action for, Minimizing Mycotoxin Exposure Worldwide." Toxins 10, no. 4: 149.

Journal article
Published: 23 February 2018 in World Mycotoxin Journal
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Aflatoxins are widely recognised as important natural contaminants of a wide range of foods, including maize and peanuts (groundnuts), which form part of the staple diet in many countries of the developing world, especially in Africa. There is a frequent misconception based on solubility considerations and developed market surveys that aflatoxins do not occur in peanut oil. Thus, the use of peanut oil in human food is frequently overlooked as a source of aflatoxin exposure, yet artisanal oil extraction from contaminated peanuts in local facilities in the developing world results in carryover of these mycotoxins into the oil. Consequently, these peanut oils can have high contamination levels. This review highlights food safety concerns and addresses inter alia the analytical adaptations required to determine the polar aflatoxins in peanut oil. The determination of aflatoxins in peanut oil was first achieved by thin-layer chromatography, which was later mostly superseded by high-performance liquid chromatography (HPLC) with fluorescence detection, or later, by mass spectrometric detection. More recently, a specially modified HPLC method with immunoaffinity column clean-up and fluorescence detection has achieved official method status at AOAC International. In addition, the review deals with toxicology, occurrence and detoxification of contaminated oil. Although various methods have been reported for detoxification of peanut oil, the toxicity of degradation products, the removal of beneficial constituents and the effect on its organoleptic properties need to be considered. This review is intended to draw attention to this often overlooked area of food safety.

ACS Style

G.S. Shephard. Aflatoxins in peanut oil: food safety concerns. World Mycotoxin Journal 2018, 11, 149 -158.

AMA Style

G.S. Shephard. Aflatoxins in peanut oil: food safety concerns. World Mycotoxin Journal. 2018; 11 (1):149-158.

Chicago/Turabian Style

G.S. Shephard. 2018. "Aflatoxins in peanut oil: food safety concerns." World Mycotoxin Journal 11, no. 1: 149-158.

Journal article
Published: 01 March 2017 in Food Control
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In developing countries the enforcement of compliance to detailed mycotoxin regulations ensures protection of the population from adverse health effects of mycotoxin exposure. In low-income or developing countries mycotoxin regulations are either lacking or poorly enforced which create scenarios where mycotoxin exposures occur above levels set by health regulatory bodies. Population groups that are the worst affected include subsistent maize growing farmer communities where mycotoxin levels are not monitored, as mono-cereal crops are cultivated and consumed locally. Other factors that aggravate the situation include the consumption of highly mycotoxin contaminated unprocessed maize, the lack of knowledge about the adverse effects as well as traditional uses of maize products not intended for human consumption during periods of food insecurity. These scenarios require ingenious ways to reduce mycotoxin exposure in poor rural communities where access to sophisticated removal techniques is not available or practically viable. Although community-based and culturally acceptable methods have, to some extent, been adapted the efficacy thereof varies due to the lack of sufficient training. Integration of these methods with more sophisticated technological methods is envisaged, and will be based on a better understanding of mycotoxin biosynthesis and fungus-host interactions on a molecular level. In addition, other methods which include the detoxification of mycotoxins utilising degradation enzymes, clay adsorbents, utilisation of non-toxigenic fungal strains and resistant maize cultivars to fungal infections are just a few approaches under scrutiny. The introduction of good agriculture practices and storage techniques and the identification of critical control points during hazard analyses need to be further explored. Introduction of mycotoxin monitoring programs and validated screening procedures to monitor exposure should be a priority in the future, to facilitate community-based and effective intervention programmes of mycotoxin reduction.

ACS Style

J.F. Alberts; M. Lilly; John Paul Rheeder; H-M. Burger; Gordon Seymour Shephard; W.C.A. Gelderblom. Technological and community-based methods to reduce mycotoxin exposure. Food Control 2017, 73, 101 -109.

AMA Style

J.F. Alberts, M. Lilly, John Paul Rheeder, H-M. Burger, Gordon Seymour Shephard, W.C.A. Gelderblom. Technological and community-based methods to reduce mycotoxin exposure. Food Control. 2017; 73 ():101-109.

Chicago/Turabian Style

J.F. Alberts; M. Lilly; John Paul Rheeder; H-M. Burger; Gordon Seymour Shephard; W.C.A. Gelderblom. 2017. "Technological and community-based methods to reduce mycotoxin exposure." Food Control 73, no. : 101-109.

Review
Published: 01 July 2016 in Journal of AOAC INTERNATIONAL
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It is over 50 years since the discovery of aflatoxins focused the attention of food safety specialists on fungal toxins in the feed and food supply. Since then, analysis of this important group of natural contaminants has advanced in parallel with general developments in analytical science, and current MS methods are capable of simultaneously analyzing hundreds of compounds, including mycotoxins, pesticides, and drugs. This profusion of data may advance our understanding of human exposure, yet constitutes an interpretive challenge to toxicologists and food safety regulators. Despite these advances in analytical science, the basic problem of the extreme heterogeneity of mycotoxin contamination, although now well understood, cannot be circumvented. The real health challenges posed by mycotoxin exposure occur in the developing world, especially among small-scale and subsistence farmers. Addressing these problems requires innovative approaches in which analytical science must also play a role in providing suitable out-of-laboratory analytical techniques.

ACS Style

Gordon Seymour Shephard. Current Status of Mycotoxin Analysis: A Critical Review. Journal of AOAC INTERNATIONAL 2016, 99, 842 -848.

AMA Style

Gordon Seymour Shephard. Current Status of Mycotoxin Analysis: A Critical Review. Journal of AOAC INTERNATIONAL. 2016; 99 (4):842-848.

Chicago/Turabian Style

Gordon Seymour Shephard. 2016. "Current Status of Mycotoxin Analysis: A Critical Review." Journal of AOAC INTERNATIONAL 99, no. 4: 842-848.

Comparative study
Published: 21 April 2016 in Food Additives & Contaminants: Part B
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Fumonisin occurrence was investigated in subsistence maize in four rural villages in each of Mbizana and Centane areas, South Africa. Samples (total 211) were analysed morphologically for Fusarium species and by high performance liquid chromatography for fumonisins. The mean incidence levels of Fusarium verticillioides in Centane good maize were 16% for both 1997 and 2000, but increased to 32% in 2003, whereas Mbizana good maize contained levels of 17% and 11% (2000 and 2003 seasons, respectively). The mean total fumonisin level in good maize in Centane for 1997 and 2000 was 575 and 975 µg/kg and 2150 µg/kg in 2003. In Mbizana, the mean total fumonisin level in good maize for 2000 was 950 µg/kg, but decreased to 610 µg/kg in 2003. The 2003 drought conditions led to a substantial increase in fumonisin levels in dry subhumid Centane, compared to humid subtropical Mbizana. This study emphasises the seasonal fluctuation in fumonisin levels.

ACS Style

J.P. Rheeder; Liana van der Westhuizen; G. Imrie; Gordon Seymour Shephard. Fusariumspecies and fumonisins in subsistence maize in the former Transkei region, South Africa: a multi-year study in rural villages. Food Additives & Contaminants: Part B 2016, 9, 176 -184.

AMA Style

J.P. Rheeder, Liana van der Westhuizen, G. Imrie, Gordon Seymour Shephard. Fusariumspecies and fumonisins in subsistence maize in the former Transkei region, South Africa: a multi-year study in rural villages. Food Additives & Contaminants: Part B. 2016; 9 (3):176-184.

Chicago/Turabian Style

J.P. Rheeder; Liana van der Westhuizen; G. Imrie; Gordon Seymour Shephard. 2016. "Fusariumspecies and fumonisins in subsistence maize in the former Transkei region, South Africa: a multi-year study in rural villages." Food Additives & Contaminants: Part B 9, no. 3: 176-184.

Original articles
Published: 20 November 2015 in Food Additives & Contaminants: Part B
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The aim of this study was to assess mycotoxin contamination of crops grown by rural subsistence farmers over two seasons (2011 and 2012) in two districts, Vhembe District Municipality (VDM, Limpopo Province) and Gert Sibande District Municiality (GSDM, Mpumalanga Province), in northern South Africa and to evaluate its impact on farmers’ productivity and human and animal health. A total of 114 maize samples were collected from 39 households over the two seasons and were analysed using a validated liquid chromatography-tandem mass spectrometry mycotoxins method. Aflatoxin B1 (AFB1) occurrence ranged from 1 to 133 µg kg−1 in VDM while AFB1 levels in GSDM were less than 1.0 µg kg−1 in all maize samples. Fumonisin B1 levels ranged from 12 to 8514 µg kg−1 (VDM) and 11–18924 µg kg−1 (GSDM) in 92% and 47% positive samples, respectively, over both seasons. Natural occurrence and contamination with both fumonisins and aflatoxins in stored home-grown maize from VDM was significantly (p < 0.0001) higher than from GSDM over both seasons.

ACS Style

P. Mngqawa; Gordon Seymour Shephard; I.R. Green; S.H. Ngobeni; T.C. De Rijk; D.R. Katerere. Mycotoxin contamination of home-grown maize in rural northern South Africa (Limpopo and Mpumalanga Provinces). Food Additives & Contaminants: Part B 2015, 9, 38 -45.

AMA Style

P. Mngqawa, Gordon Seymour Shephard, I.R. Green, S.H. Ngobeni, T.C. De Rijk, D.R. Katerere. Mycotoxin contamination of home-grown maize in rural northern South Africa (Limpopo and Mpumalanga Provinces). Food Additives & Contaminants: Part B. 2015; 9 (1):38-45.

Chicago/Turabian Style

P. Mngqawa; Gordon Seymour Shephard; I.R. Green; S.H. Ngobeni; T.C. De Rijk; D.R. Katerere. 2015. "Mycotoxin contamination of home-grown maize in rural northern South Africa (Limpopo and Mpumalanga Provinces)." Food Additives & Contaminants: Part B 9, no. 1: 38-45.

Original articles
Published: 18 September 2015 in Food Additives & Contaminants: Part A
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Traditional and improved varieties of maize, pearl millet and sorghum were planted by small-scale farmers under the direction of the International Institute for Tropical Agriculture in two Nigerian agro-ecological zones: the Sudan Savanna and the Northern Guinea Savanna. Samples were collected for the determination of Fusarium infection and fumonisin (B1, B2 and B3) contamination. A previous paper reported Aspergillus infection and aflatoxin contamination of these samples. Fusarium infection levels, measured by per cent kernels infected, were modest with mean levels for the above cereals of 16% ± 11% (SD), 12% ± 7% and 13% ± 16%, respectively. However, the Fusarium species recovered from maize were predominantly the fumonisin producers F. verticillioides and F. proliferatum, together making an infection rate of 15% ± 10%, whereas these species were present to a limited extent only in the other two cereals, 1% ± 1% for pearl millet and 2% ± 6% for sorghum. Fumonisin contamination was variable but reflected the diversity of Fusarium producers in these three cereals. Mean levels were 228 ± 579 µg kg–1 (range < 5–2860 µg kg–1) for maize, 18 ± 7 µg kg–1 (range = 6–29 µg kg–1) for pearl millet and 131 ± 270 µg kg–1 (range < 5–1340 µg kg–1) for sorghum. Together with previous results on aflatoxin, this study confirmed the co-occurrence of aflatoxins and fumonisins in maize as well as in the traditional African cereals, millet and sorghum (89% co-occurrence across all three cereals). The low fumonisin levels may be ascribed to the use of good agricultural practices. Of the Fusarium species present, those in maize consisted mainly of fumonisin producers, the opposite of what was observed in pearl millet and sorghum. It is concluded that replacement of maize by pearl millet and sorghum could improve food safety with regards to aflatoxin B and fumonisin B exposure.

ACS Style

Hester F. Vismer; Gordon S. Shephard; John P. Rheeder; Liana van der Westhuizen; Ranajit Bandyopadhyay. Relative severity of fumonisin contamination of cereal crops in West Africa. Food Additives & Contaminants: Part A 2015, 32, 1952 -1958.

AMA Style

Hester F. Vismer, Gordon S. Shephard, John P. Rheeder, Liana van der Westhuizen, Ranajit Bandyopadhyay. Relative severity of fumonisin contamination of cereal crops in West Africa. Food Additives & Contaminants: Part A. 2015; 32 (11):1952-1958.

Chicago/Turabian Style

Hester F. Vismer; Gordon S. Shephard; John P. Rheeder; Liana van der Westhuizen; Ranajit Bandyopadhyay. 2015. "Relative severity of fumonisin contamination of cereal crops in West Africa." Food Additives & Contaminants: Part A 32, no. 11: 1952-1958.

Comparative study
Published: 01 October 2014 in Toxicological Sciences
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The differential risk of exposure to fumonisin (FB), deoxynivalenol (DON), and zearalenone (ZEA) mycotoxins to the South African population, residing in the nine Provinces was assessed during a cross-sectional grain consumer survey. The relative per capita maize intake (g/day) was stratified by gender, ethnicity, and Province and the probable daily intake (PDI) for each mycotoxin (ng/kg body weight/day) calculated utilizing SPECIAL and SUPER dry milled maize fractions representing different exposure scenarios. Men consumed on an average more maize (173 g/day) than women (142 g/day) whereas the black African ethnic group had the highest intake (279 g/day) followed by the Colored group (169 g/day) with the Asian/Indian and White groups consuming lower quantities of 101 and 80 g/day, respectively. The estimated mean PDIs for the various subgroups and Provinces, utilizing the different dry milled maize fractions, were below the provisional maximum tolerable daily intake (PMTDI) for each mycotoxin. A distinct and more sensitive mycotoxin risk assessment model (MYCORAM) for exposure, stratified by Province and ethnicity were developed utilizing specific maize intake increments (g/kg body weight/day) that provides information on the percentage of the population exposed above the PMTDI for each mycotoxin. Evaluation of the MYCORAM utilizing commercial and experimentally derived SPECIAL milling fractions, containing predefined mycotoxins levels, predicts the percentage of maize consumers exposed above the respective PMTDI. Safety modeling using the MYCORAM could also predict a maximum tolerated level adequate to safeguard all South African maize consumers including the most vulnerable groups.

ACS Style

Hester-Mari Burger; Martani J. Lombard; Gordon Seymour Shephard; Natasha Danster-Christians; Wentzel C.A. Gelderblom. Development and Evaluation of a Sensitive Mycotoxin Risk Assessment Model (MYCORAM). Toxicological Sciences 2014, 141, 387 -397.

AMA Style

Hester-Mari Burger, Martani J. Lombard, Gordon Seymour Shephard, Natasha Danster-Christians, Wentzel C.A. Gelderblom. Development and Evaluation of a Sensitive Mycotoxin Risk Assessment Model (MYCORAM). Toxicological Sciences. 2014; 141 (2):387-397.

Chicago/Turabian Style

Hester-Mari Burger; Martani J. Lombard; Gordon Seymour Shephard; Natasha Danster-Christians; Wentzel C.A. Gelderblom. 2014. "Development and Evaluation of a Sensitive Mycotoxin Risk Assessment Model (MYCORAM)." Toxicological Sciences 141, no. 2: 387-397.

Journal article
Published: 01 January 2014 in World Mycotoxin Journal
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Among the many hurdles faced by developing countries, food safety with respect to mycotoxin contamination has frequently been side-lined with few countries having regulations and with poor enforcement where they do exist. Whereas commodity exporters may have the resources for engaging commercial accredited laboratories, the greatest challenge is found in rural, predominantly subsistence or smallholder farms, where conventional food surveillance is lacking. Rapid methods, designed for use in field conditions, where electricity is lacking or unreliable, can offer some solution to these problems. The World Food Programme's ‘Blue Box’ is an example of how technology can be adapted for these rural areas. The recent development of temperature stable aptamers and smart mobile phone technology may further enhance efforts to provide food safety in these areas.

ACS Style

Gordon Seymour Shephard; W.C.A. Gelderblom. Rapid testing and regulating for mycotoxin concerns: a perspective from developing countries. World Mycotoxin Journal 2014, 7, 431 -437.

AMA Style

Gordon Seymour Shephard, W.C.A. Gelderblom. Rapid testing and regulating for mycotoxin concerns: a perspective from developing countries. World Mycotoxin Journal. 2014; 7 (4):431-437.

Chicago/Turabian Style

Gordon Seymour Shephard; W.C.A. Gelderblom. 2014. "Rapid testing and regulating for mycotoxin concerns: a perspective from developing countries." World Mycotoxin Journal 7, no. 4: 431-437.

Journal article
Published: 01 December 2013 in Food and Chemical Toxicology
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Subsistence farmers are exposed to a range of mycotoxins. This study applied novel urinary multi-mycotoxin LC-MS/MS methods to determine multiple exposure biomarkers in the high oesophageal cancer region, Transkei, South Africa. Fifty-three female participants donated part of their maize-based evening meal and first void morning urine, which was analysed both with sample clean-up (single and multi-biomarker) and by a 'dilute-and-shoot' multi-biomarker method. Results were corrected for recovery with LOD for not detected. A single biomarker method detected fumonisin B1 (FB1) (87% incidence; mean±standard deviation 0.342±0.466 ng/mg creatinine) and deoxynivalenol (100%; mean 20.4±49.4 ng/mg creatinine) after hydrolysis with β-glucuronidase. The multi-biomarker 'dilute-and-shoot' method indicated deoxynivalenol-15-glucuronide was predominantly present. A multi-biomarker method with β-glucuronidase and immunoaffinity clean-up determined zearalenone (100%; 0.529±1.60 ng/mg creatinine), FB1 (96%; 1.52±2.17 ng/mg creatinine), α-zearalenol (92%; 0.614±1.91 ng/mg creatinine), deoxynivalenol (87%; 11.3±27.1 ng/mg creatinine), β-zearalenol (75%; 0.702±2.95 ng/mg creatinine) and ochratoxin A (98%; 0.041±0.086 ng/mg creatinine). These demonstrate the value of multi-biomarker methods in measuring exposures in populations exposed to multiple mycotoxins. This is the first finding of urinary deoxynivalenol, zearalenone, their conjugates, ochratoxin A and zearalenols in Transkei.

ACS Style

Gordon S. Shephard; Hester-Mari Burger; Lucia Gambacorta; Yun Yun Gong; Rudolf Krska; John P. Rheeder; Michele Solfrizzo; Chou Srey; Michael Sulyok; Angelo Visconti; Benedikt Warth; Liana van der Westhuizen. Multiple mycotoxin exposure determined by urinary biomarkers in rural subsistence farmers in the former Transkei, South Africa. Food and Chemical Toxicology 2013, 62, 217 -225.

AMA Style

Gordon S. Shephard, Hester-Mari Burger, Lucia Gambacorta, Yun Yun Gong, Rudolf Krska, John P. Rheeder, Michele Solfrizzo, Chou Srey, Michael Sulyok, Angelo Visconti, Benedikt Warth, Liana van der Westhuizen. Multiple mycotoxin exposure determined by urinary biomarkers in rural subsistence farmers in the former Transkei, South Africa. Food and Chemical Toxicology. 2013; 62 ():217-225.

Chicago/Turabian Style

Gordon S. Shephard; Hester-Mari Burger; Lucia Gambacorta; Yun Yun Gong; Rudolf Krska; John P. Rheeder; Michele Solfrizzo; Chou Srey; Michael Sulyok; Angelo Visconti; Benedikt Warth; Liana van der Westhuizen. 2013. "Multiple mycotoxin exposure determined by urinary biomarkers in rural subsistence farmers in the former Transkei, South Africa." Food and Chemical Toxicology 62, no. : 217-225.

Book chapter
Published: 18 November 2013 in Food Safety Management
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Nuts, oilseeds and legumes are important dietary constituents to combat chronic diseases of lifestyle due to the presence of important dietary macro- and micronutrients. However, many potential hazards associated with the harvesting, storage and processing occur of which mycotoxin contamination appears to be one of the major causes for economic losses of foodstuff and health-related risks resulting in many animal and human diseases. The major toxigenic fungal genera are Aspergillus, Penicillium and Fusarium, producing a diverse group of mycotoxins with adverse toxicological effects of which the aflatoxins, ochratoxin A, deoxynivalenol, zearalenone and the fumonisins are some of the most common and well-researched mycotoxins. The levels of these mycotoxins, among others, are well controlled in food and feed in developed countries, whereas their regulation in developing countries is poor or lacking. Mycotoxin control in food commodities involves a range of interventions to secure safe food based on a farm to fork approach, including good agricultural, storage and processing practices, which form part of the Hazard Analysis Critical Control Points (HACCP) system. For example, pistachio nuts are associated with a high risk for pre-harvest aflatoxin contamination due to insect damage and “early splitting” of the fruit hulls, as well as during the extensive post-harvest processing of the nuts. The generic example of an HACCP plan for pistachio processing identifies five Critical Control Points (CCPs) which need careful monitoring to ensure a consumer product which adheres to international aflatoxin regulations. These CCPs include steps related to the use of flotation tanks, adequate removal of hull debris from the nut shells, proper drying and sorting prior to packaging or export. Key to this HACCP plan is good communication between pistachio producer and processor. These and other control parameters to reduce mycotoxin contamination are critically reviewed in the current chapter which will be important in food safety management regarding the control of mycotoxin exposure.

ACS Style

W.C.A. Gelderblom; G.S. Shephard; John Paul Rheeder; S.K. Sathe; A. Ghiasi; Y. Motarjemi. Edible Nuts, Oilseeds and Legumes. Food Safety Management 2013, 301 -324.

AMA Style

W.C.A. Gelderblom, G.S. Shephard, John Paul Rheeder, S.K. Sathe, A. Ghiasi, Y. Motarjemi. Edible Nuts, Oilseeds and Legumes. Food Safety Management. 2013; ():301-324.

Chicago/Turabian Style

W.C.A. Gelderblom; G.S. Shephard; John Paul Rheeder; S.K. Sathe; A. Ghiasi; Y. Motarjemi. 2013. "Edible Nuts, Oilseeds and Legumes." Food Safety Management , no. : 301-324.

Research article
Published: 20 August 2013 in Journal of Agricultural and Food Chemistry
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Maize harvested in the Centane region of the former Transkei, Eastern Cape Province, South Africa, by subsistence farmers has been shown over many seasons to be contaminated with fumonisin mycotoxins. However, there are limited data on the presence of other mycotoxins. Two multimycotoxin LC-MS/MS methods were applied to good and moldy maize samples, as separated by the farmers themselves from the 2011 harvest. One method involved extract cleanup on multitoxin immunoaffinity columns before LC-MS/MS analysis for aflatoxins, fumonisins, deoxynivalenol (DON), zearalenone (ZEN), and T-2 and HT-2 toxins. The other method was based on a “dilute-and-shoot” approach for the above mycotoxins and a wide range of other fungal secondary metabolites. Both methods showed high incidences of fumonisins B1 and B2 (FB1 and FB2) in good maize (100% for both by the first method, means were 2083 and 927 μg/kg for the two analogues; 93% for both by the second method, positive means of 2764 and 1050 μg/kg, respectively). All samples of moldy maize were contaminated (mean FB1 of 27.64 and 35.98 mg/kg, respectively; mean FB2 of 10.58 and 14.14 mg/kg, respectively). Comparison of the two methods for FB1 and FB2 over the entire range of samples gave R2 values 0.9144 and 0.8859, respectively. Low levels of DON were found by both methods (positive means of 12 and 4.7 μg/kg in good maize, respectively, and of 14 and 5.8 μg/kg in moldy maize, respectively). ZEN was determined with positive means of 108 and 25 μg/kg in good maize, respectively, and of 111 and 135 μg/kg in moldy maize, respectively. No aflatoxins, OTA, or T-2 or HT-2 toxins were detected. A wide range of other Fusarium, Aspergillus, Alternaria, and Penicillium mycotoxins and secondary metabolites were determined.

ACS Style

Gordon S. Shephard; Hester-Mari Burger; Lucia Gambacorta; Rudolf Krska; Stephen P. Powers; John P. Rheeder; Michele Solfrizzo; Michael Sulyok; Angelo Visconti; Benedikt Warth; Liana van der Westhuizen. Mycological Analysis and Multimycotoxins in Maize from Rural Subsistence Farmers in the Former Transkei, South Africa. Journal of Agricultural and Food Chemistry 2013, 61, 8232 -8240.

AMA Style

Gordon S. Shephard, Hester-Mari Burger, Lucia Gambacorta, Rudolf Krska, Stephen P. Powers, John P. Rheeder, Michele Solfrizzo, Michael Sulyok, Angelo Visconti, Benedikt Warth, Liana van der Westhuizen. Mycological Analysis and Multimycotoxins in Maize from Rural Subsistence Farmers in the Former Transkei, South Africa. Journal of Agricultural and Food Chemistry. 2013; 61 (34):8232-8240.

Chicago/Turabian Style

Gordon S. Shephard; Hester-Mari Burger; Lucia Gambacorta; Rudolf Krska; Stephen P. Powers; John P. Rheeder; Michele Solfrizzo; Michael Sulyok; Angelo Visconti; Benedikt Warth; Liana van der Westhuizen. 2013. "Mycological Analysis and Multimycotoxins in Maize from Rural Subsistence Farmers in the Former Transkei, South Africa." Journal of Agricultural and Food Chemistry 61, no. 34: 8232-8240.

Journal article
Published: 01 August 2013 in World Mycotoxin Journal
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Maize is the predominant food source contaminated by fumonisins and this has particular health risks for communities consuming maize as a staple diet. The main biochemical effect of fumonisins is the inhibition of ceramide biosynthesis causing an increase in sphingoid bases and sphingoid base 1-phosphates and a depletion of the complex sphingolipids, thereby disrupting lipid metabolism and sphingolipid-mediated processes and signalling systems. Attempts to use the elevation of sphinganine as a human biomarker of fumonisin exposure have to date been unsuccessful. Consequently, recent research has focussed on developing a urinary exposure biomarker based on the measurement of the nonmetabolised toxin. In animals, fumonisins are poorly absorbed in the gut and are mostly excreted unmetabolised in faeces, with only a small percentage (0.25-2.0%) in urine. This appears to also be true in humans were fumonisin B1 (FB1) is detectable in urine soon after exposure, but in very small amounts relative to total intake. However, with modern sensitive and selective analytical methods such as liquid chromatography-tandem mass spectrometry, these low levels can be readily determined. The first study to show a positive correlation between consumption of maize and urinary FB1 was conducted in a Mexican population consuming tortillas as a staple food. Further validation of this relationship was achieved in a South African subsistence farming community with a positive correlation between urinary FB1 and fumonisin exposure, as assessed by food analysis and food intake data. The most recent developments are aimed at measuring multiple mycotoxin biomarkers in urine, including FB1. Current exposure studies in Guatemala are combining the urinary biomarker with measurement of sphinganine-1-phosphate in blood spots as a measure of biochemical effect. Thus, the urinary FB1 biomarker could contribute considerably in assessing the adverse health impact of fumonisin exposure.

ACS Style

Liana Van Der Westhuizen; Gordon Seymour Shephard; W.C.A. Gelderblom; O. Torres; R.T. Riley. Fumonisin biomarkers in maize eaters and implications for human disease. World Mycotoxin Journal 2013, 6, 223 -232.

AMA Style

Liana Van Der Westhuizen, Gordon Seymour Shephard, W.C.A. Gelderblom, O. Torres, R.T. Riley. Fumonisin biomarkers in maize eaters and implications for human disease. World Mycotoxin Journal. 2013; 6 (3):223-232.

Chicago/Turabian Style

Liana Van Der Westhuizen; Gordon Seymour Shephard; W.C.A. Gelderblom; O. Torres; R.T. Riley. 2013. "Fumonisin biomarkers in maize eaters and implications for human disease." World Mycotoxin Journal 6, no. 3: 223-232.

Journal article
Published: 01 July 2013 in International Journal of Food Microbiology
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Mycotoxin contamination of maize and maize-based food and feed products poses a health risk to humans and animals if not adequately controlled and managed. The current study investigates the effect of dry milling on the reduction of fumonisins (FB), deoxynivalenol (DON) and zearalenone (ZEA) in maize. Five composite samples, constructed to represent different mycotoxin contamination levels were degermed yielding degermed maize and the germ. The degermed maize was milled under laboratory conditions and four major milling fractions (SPECIAL, SUPER, semolina (SEM) and milling hominy feed) collected. The whole maize, degermed maize and total hominy feed (germ+milling hominy feed) were reconstructed to ensure homogenous samples for mycotoxin analyses. For comparison, commercial dry milling fractions (whole maize, SPECIAL, SUPER and total hominy feed), collected from three South African industrial mills, were analysed for the same mycotoxins and hence a more accurate assessment of the distribution between the different milling fractions. The distribution of the mycotoxins during the experimental dry milling of the degermed maize differs, with FB mainly concentrated in the SPECIAL, DON in the SEM whereas ZEA was equally distributed between the two milling fractions. Distribution of mycotoxins between the fractions obtained during commercial dry milling generally provided similar results with the total hominy feed containing the highest and the SUPER milling fractions the lowest mycotoxin levels although variations existed. Although milling is an effective way to reduce mycotoxins in maize, kernel characteristics and resultant fungal colonisation may impact on the distribution of specific mycotoxins among the different milling fractions. Differences in industrial dry milling practices and problems encountered in sampling bulk maize remain a large problem in assessing mycotoxin contamination in milling fractions intended for human consumption.

ACS Style

H-M. Burger; G.S. Shephard; W. Louw; John Paul Rheeder; W.C.A. Gelderblom. The mycotoxin distribution in maize milling fractions under experimental conditions. International Journal of Food Microbiology 2013, 165, 57 -64.

AMA Style

H-M. Burger, G.S. Shephard, W. Louw, John Paul Rheeder, W.C.A. Gelderblom. The mycotoxin distribution in maize milling fractions under experimental conditions. International Journal of Food Microbiology. 2013; 165 (1):57-64.

Chicago/Turabian Style

H-M. Burger; G.S. Shephard; W. Louw; John Paul Rheeder; W.C.A. Gelderblom. 2013. "The mycotoxin distribution in maize milling fractions under experimental conditions." International Journal of Food Microbiology 165, no. 1: 57-64.