Aflatoxin Regulations in a Network of Global Maize Trade

Wu, Felicia; Güçlü, Hasan

doi:10.1371/journal.pone.0045151

Cited by 125 publications

(115 citation statements)

References 22 publications

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“…The economic impact is immense because fungal mycotoxin contamination is estimated to affect one quarter of the world's food crops (CAST 2003) including maize, cotton and peanuts [4]. Crop losses are estimated to cost between $1 and $1.5 billion/year in the United States [5]. These losses do not account for livestock losses or the impact on human health or healthcare costs from exposure to the fungi or to the toxins.…”

Section: Introductionmentioning

confidence: 99%

Monitoring MVOC Profiles over Time from Isolates of Aspergillus flavus Using SPME GC-MS

Sun¹,

Wood-Jones²,

Wang³

et al. 2014

JACEN

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Fungi produce a variety of microbial volatile organic compounds (MVOCs) during primary and secondary metabolism. The fungus, Aspergillus flavus, is a human, animal and plant pathogen which produces aflatoxin, one of the most carcinogenic substances known. In this study, MVOCs were analyzed using solid phase microextraction (SPME) combined with GCMS from two genetically different A. flavus strains, an aflatoxigenic strain, NRRL 3357, and a non-aflatoxigenic strain, NRRL 21882. A PDMS/CAR SPME fiber was used over 30 days to observe variations in MVOCs over time. The relative percentage of individual chemicals in several chemical classes (alcohols, aldehydes, esters, furans, hydrocarbons, ketones, and organic acids) was shown to change considerably during the varied fungal growth stages. This changing chemical profile reduces the likelihood of finding a single chemical that can be used consistently as a biomarker for fungal strain identification. In our study, discriminant analysis techniques were successfully conducted using all identified and quantified MVOCs enabling discrimination of the two A. flavus strains over the entire 30-day period. This study underscores the potential of using SPME GCMS coupled with multivariate analysis for fungi strain identification.

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Section: Introductionmentioning

confidence: 99%

Monitoring MVOC Profiles over Time from Isolates of Aspergillus flavus Using SPME GC-MS

Sun¹,

Wood-Jones²,

Wang³

et al. 2014

JACEN

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“…These AFs are toxic and their main adverse effects on humans are hepatocarcinoma (Qian et al, 1994; IARC, 2014), immune system deficiency (Jiang et al, 2005), reduced child growth (Gong et al, 2004) and increased risks of stillborn or newborn jaundice (Shuaib et al, 2010). To reduce those multiple effects, many countries have implemented maximum authorized levels of AFs in food and feed (Wu & Guclu, 2012). AF biosynthesis is coded by a 80 kb long DNA sequence.…”

mentioning

confidence: 99%

Reduction of aflatoxin production by Aspergillus flavus and Aspergillus parasiticus in interaction with Streptomyces

et al. 2015

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The aim of this study is to investigate aflatoxin gene expression during Streptomyces-Aspergillus interaction. Aflatoxins are carcinogenic compounds produced mainly by Aspergillus flavus and Aspergillus parasiticus. A previous study has shown that Streptomyces-A. flavus interaction can reduce aflatoxin content in vitro. Here, we first validated this same effect in the interaction with A. parasiticus. Moreover, we showed that growth reduction and aflatoxin content were correlated in A. parasiticus but not in A. flavus. Secondly, we investigated the mechanisms of action by reversetranscriptase quantitative PCR. As microbial interaction can lead to variations in expression of household genes, the most stable [act1, btub (and cox5 for A. parasiticus)] were chosen using geNorm software. To shed light on the mechanisms involved, we studied during the interaction the expression of five genes (aflD, aflM, aflP, aflR and aflS). Overall, the results of aflatoxin gene expression showed that Streptomyces repressed gene expression to a greater level in A. parasiticus than in A. flavus. Expression of aflR and aflS was generally repressed in both Aspergillus species. Expression of aflM was repressed and was correlated with aflatoxin B1 content. The results suggest that aflM expression could be a potential aflatoxin indicator in Streptomyces species interactions. Therefore, we demonstrate that Streptomyces can reduce aflatoxin production by both Aspergillus species and that this effect can be correlated with the repression of aflM expression. INTRODUCTIONAflatoxins (AFs) are polyketide-derived furanocoumarins. They are produced by fungi of the genus Aspergillus (including Aspergillus flavus and Aspergillus parasiticus) in agricultural foodstuffs (maize, hazelnut, peanut, etc.) (Giorni et al., 2007;Passone et al., 2010). These AFs are toxic and their main adverse effects on humans are hepatocarcinoma (Qian et al., 1994; IARC, 2014), immune system deficiency (Jiang et al., 2005), reduced child growth (Gong et al., 2004) and increased risks of stillborn or newborn jaundice (Shuaib et al., 2010). To reduce those multiple effects, many countries have implemented maximum authorized levels of AFs in food and feed (Wu & Guclu, 2012). AF biosynthesis is coded by a 80 kb long DNA sequence. The latter is a cluster containing 30 putative genes characterized in both A. flavus and A. parasiticus (Yu, 2012). For structural genes, early (as aflD), medium (as aflM) and late (as aflP) genes are denominated (Fig. S1, available in the online Supplementary Material). The gene aflD encodes a reductase enzyme involved in the conversion of norsolorinic acid to averantin (Papa, 1982); aflM is required for the conversion of versicolorin A to demethylsterigmatocystin (Skory et al., 1992); and aflP encodes a methyltransferase converting sterigmatocystin to O-methylsterigmatocystin (Bhatnagar et al., 1988). Two cluster-specific regulators are also known: aflR encodes a transcription activator that binds a consensus sequence in the promoter regions of AF ...

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“…A recent report by the FAO on mycotoxins shows over 100 countries worldwide had set regulatory limits on allowable mycotoxins levels in human and animal feeds Wu and Guclu, 2012).…”

Section: Page 29mentioning

confidence: 99%

“…Regulatory limits are rarely in place or not properly implemented due to improper testing equipment, no monitoring and surveillance system in place, and poor management of grains and oilseeds (Wild and Gong, 2010;Wu and Guclu, 2012). Table 6 shows maximum acceptable limits of mycotoxins in maize for some selected countries.…”

Section: Current Regulations Encompass About 13 Different Groups Of Mmentioning

confidence: 99%

Current Maize Production, Postharvest Losses and the Risk of Mycotoxins Contamination in Tanzania

Suleiman¹,

Rosentrater²

2015

2015 ASABE International Meeting

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Agriculture is the backbone of Tanzanian economy. It accounts for about one-third of the gross domestic product (GDP), provides 85 percent of all exports and saves as a livelihood to over 80 percent of the total population. Maize is the primary staple crop; it's grown in nearly all agro-ecological zones in the country. Tanzania is a major maize producer in Sub-Saharan Africa. In the last four decades, Tanzania has ranked among the top 25 maize producing countries in the world. In the 2013/14 growing seasons Tanzania produced over half billion metric tons of maize of these maize smallholder farmers produced around 85%. Despite the steady production of maize over the past three decades, post-harvest losses of maize remained significant, up to 30-40 % in some rural areas. Post-harvest handling, poor infrastructure, weather variability, biotic factors such as insects and pests, bacteria, pathogens, viruses, and fungi, often aggravate such losses. Mycotoxin producing fungi pose a major risk. Mycotoxins are toxic secondary metabolites of fungi that frequently contaminate the maize in the field and/or during storage. Mycotoxin contamination of maize poses a health risk to humans and animals if not properly managed. The most important mycotoxins in Tanzania are the aflatoxins, fumonisins and Ochratoxin. The objective of this paper was to review current literature on the production trends, consumption, post-harvest losses, and mycotoxins contamination of maize and to provide strategies to control and prevent postharvest losses and mycotoxins contamination in Tanzania. Agriculture is the backbone of Tanzanian economy. It accounts for about one-third of the gross domestic product (GDP), provides 85 percent of all exports and saves as a livelihood to over 80 percent of the total population. Maize is the primary staple crop; it's grown in nearly all agro-ecological zones in the country. Tanzania is a major maize producer in Sub-Saharan Africa. In the last four decades, Tanzania has ranked among the top 25 maize producing countries in the world. In the 2013/14 growing seasons Tanzania produced over half billion metric tons of maize of these maize smallholder farmers produced around 85%. Despite the steady production of maize over the past three decades, post-harvest losses of maize remained significant, up to 30-40 % in some rural areas. Post-harvest handling, poor infrastructure, weather variability, biotic factors such as insects and pests, bacteria, pathogens, viruses, and fungi, often aggravate such losses. Mycotoxin producing fungi pose a major risk. Mycotoxins are toxic secondary metabolites of fungi that frequently contaminate the maize in the field and/or during storage. Mycotoxin contamination of maize poses a health risk to humans and animals if not properly managed. The most important mycotoxins in Tanzania are the aflatoxins, fumonisins and Ochratoxin. The objective of this paper was to review current literature on the production trends, consumption, post-harvest losses, and mycotoxins contamination of mai...

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Aflatoxin Regulations in a Network of Global Maize Trade

Cited by 125 publications

References 22 publications

Monitoring MVOC Profiles over Time from Isolates of Aspergillus flavus Using SPME GC-MS

Monitoring MVOC Profiles over Time from Isolates of Aspergillus flavus Using SPME GC-MS

Reduction of aflatoxin production by Aspergillus flavus and Aspergillus parasiticus in interaction with Streptomyces

Current Maize Production, Postharvest Losses and the Risk of Mycotoxins Contamination in Tanzania

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