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Potential economic losses to the USA corn industry from aflatoxin contamination
Food Additives & Contaminants Part A
Abstract
Mycotoxins, toxins produced by fungi that colonise food crops, can pose a heavy economic burden to the United States corn industry. In terms of economic burden, aflatoxins are the most problematic mycotoxins in US agriculture. Estimates of their market impacts are important in determining the benefits of implementing mitigation strategies within the US corn industry, and the value of strategies to mitigate mycotoxin problems. Additionally, climate change may cause increases in aflatoxin contamination in corn, greatly affecting the economy of the US Midwest and all sectors in the US and worldwide that rely upon its corn production. We propose two separate models for estimating the potential market loss to the corn industry from aflatoxin contamination, in the case of potential near-future climate scenarios (based on aflatoxin levels in Midwest corn in warm summers in the last decade). One model uses probability of acceptance based on operating characteristic (OC) curves for aflatoxin sampling and testing, while the other employs partial equilibrium economic analysis, assuming no Type 1 or Type 2 errors, to estimate losses due to proportions of lots above the US Food and Drug Administration (FDA) aflatoxin action levels. We estimate that aflatoxin contamination could cause losses to the corn industry ranging from 1.68 billion annually in the United States, if climate change causes more regular aflatoxin contamination in the Corn Belt as was experienced in years such as 2012. The wide range represents the natural variability in aflatoxin contamination from year to year in US corn, with higher losses representative of warmer years.
... [7] AF in general Climate change-related AF contamination could cost the US corn industry USD 52.1 million to USD 1.68 billion annually. [10] AFB1 Consuming 20-120 µg/kg of AFB1 per day for one to three weeks can cause acute toxicity and may be lethal. [12] Over 350 AF have been identified in fungi, and their distribution in agricultural products poses a significant global challenge [7]. ...
... Mycotoxin contamination drives up costs for crops, such as corn, mostly due to necessities like increased testing, lower prices received for contaminated loads, potential consumer lawsuits, and reduced production of the livestock industry. In fact, AF represents the greatest threat to the US corn industry [10]. Table 1 summarizes the health and economic effects of aflatoxins. ...
... [7] AF in general Climate change-related AF contamination could cost the US corn industry USD 52.1 million to USD 1.68 billion annually. [10] AFB1 Consuming 20-120 µg/kg of AFB1 per day for one to three weeks can cause acute toxicity and may be lethal. [12] AFB1 Teratogenic effects were observed in rabbits when administrated AFB1 orally during gestation days 6-18 at a dose of 100 µg/kg. ...
Aflatoxins (AF) are highly toxic secondary metabolites produced by various species of Aspergillus, posing significant health risks to humans and animals. The four most prominent types are aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1), and aflatoxin G2 (AFG2). These mycotoxins are prevalent in various environments, including water sources and food products. Among these mycotoxins, AFB1 is recognized as the most toxic, mutagenic, and carcinogenic to humans. Consequently, most efforts to mitigate the impact of AF have been focused on AFB1, with photocatalysis emerging as a promising solution. Recent research has demonstrated that using semiconductor photocatalysis, particularly titanium dioxide (TiO2), combined with UV–visible irradiation significantly enhances the efficiency of AF degradation. TiO2 is noted for its high activity under UV irradiation, non-toxicity, and excellent long-term stability, making it a favorable choice for photocatalytic applications. Furthermore, TiO2 combined with visible light has demonstrated the ability to reduce AF contamination in food products. This article summarizes the working conditions and degradation rates achieved, as well as the advantages, limitations, and areas of opportunity of these methodologies for the degradation of AF and preventing their production, thereby enhancing food and water safety.
... Additionally, the yearly costs of managing aflatoxin contamination in the U.S., including testing and mitigation techniques, range from $20 to $50 million. Farmers and grain handlers are further taxed by economic losses that can surpass $1 billion during years of increased contamination, such as drought years in the U.S. Corn Belt [49,50]. ...
... High temperatures and drought, like those that occurred in the Corn Belt in some years, raise the possibility of contamination and call for more regular testing. Due to varying contamination levels, these environmental conditions not only increase the risk of contamination but also increase economic losses, making it challenging for exporters to predict financial results [50]. Improved aflatoxin control measures, worldwide regulatory alignment, and cost-effective testing technologies are urgently needed to decrease the financial taxes on global trade. ...
Aflatoxins, toxic secondary metabolites produced by Aspergillus genus, represent a significant risk to food safety and public health. They are known for their hepatotoxic and carcinogenic affects, which pose severe health risks to human and animals. This chapter delves into the biochemistry of aflatoxins, exploring their diversity and the structural characteristics of the four major aflatoxins (B1, B2, G1, and G2). Furthermore, it explores the complex biosynthesis pathway for aflatoxin B1 (AFB1) in Aspergillus genus involving 27 steps that are mainly regulated by specific gene clusters and transcription factors (aflR and aflJ), alongside environmental modulators such as carbon and nitrogen. This chapter also addresses the contamination of various crops by aflatoxins, driven by many environmental factors such as temperature, moisture, and pH leading to considerable economic losses and strict regulatory limits set by the European Union (EU) and the U.S. Food and Drug Administration (FDA). Finally, the health risks associated with aflatoxin exposure, particularly hepatotoxicity, hepatocellular carcinoma, mitochondrial damage, and apoptosis, with insights into molecular pathways are reported in this chapter.
... Ingesting high concentrations of aflatoxins causes acute toxicity, resulting in severe illness and death, while long-term chronic lowdose exposure to aflatoxins leads to the development of liver cancer [4][5][6]. Regulation of aflatoxins in food and feed affords consumer safety; however, contamination still results in significant economic losses [2,7]. Globally, mycotoxins are estimated to affect one-quarter of crops each year, with aflatoxins regarded as the most important due to their carcinogenic properties [8]. ...
... This will likely lead to even more contamination and exacerbate monetary losses for the corn industry. Potential economic losses due to aflatoxin contamination of corn are estimated to be greater than USD 1.6 billion per year in the United States if global warming continues [7]. Corn plants that are resistant to aflatoxin ...
Aspergillus flavus, a fungus known for producing aflatoxins, poses significant threats to agriculture and global health. Flavonoids, plant-derived compounds, inhibit A. flavus proliferation and mitigate aflatoxin production, although the precise molecular and physical mechanisms underlying these effects remain poorly understood. In this study, we investigated three flavonoids—apigenin, luteolin, and quercetin—applied to A. flavus NRRL 3357. We determined the following: (1) glycosylated luteolin led to a 10% reduction in maximum fungal growth capacity; (2) quercetin affected cell wall integrity by triggering extreme mycelial collapse, while apigenin and luteolin caused peeling of the outer layer of cell wall; (3) luteolin exhibited the highest antioxidant capacity in the environment compared to apigenin and quercetin; (4) osmotic stress assays did not reveal morphological defects; (5) flavonoids promoted cell adherence, a precursor for biofilm formation; and (6) RNA sequencing analysis revealed that flavonoids impact expression of putative cell wall and plasma membrane biosynthesis genes. Our findings suggest that the differential effects of quercetin, luteolin, and apigenin on membrane integrity and biofilm formation may be driven by their interactions with fungal cell walls. These insights may inform the development of novel antifungal additives or plant breeding strategies focusing on plant-derived compounds in crop protection.
... Aflatoxin contamination of maize grown in the United States resulted in an estimated economic losses of $686.6 million in 2013 (Mitchell et al. 2016). Apart from the cost of testing, the economic loss caused by aflatoxin in 16 U.S. states averaged 17.5 to 24.5 million dollars from 2001 to 2016 (Yu et al. 2020). ...
... Apart from the cost of testing, the economic loss caused by aflatoxin in 16 U.S. states averaged 17.5 to 24.5 million dollars from 2001 to 2016 (Yu et al. 2020). Under the changing climate scenario, aflatoxin contamination is predicted to cost the U.S. maize industry $52.1 million to $1.68 billion per year (Mitchell et al. 2016). Aspergillus flavus can invade maize at any developmental stage, from pre-harvest to storage. ...
Maize (Zea mays), a major food crop worldwide, is susceptible to infection by the saprophytic fungus Aspergillus flavus that can produce the carcinogenic metabolite aflatoxin (AF) especially under climate change induced abiotic stressors
that favor mold growth. Several studies have used “-omics” approaches to identify genetic elements with potential roles in AF resistance, but there is a lack of research identifying the involvement of small RNAs such as microRNAs (miRNAs) in maize-A. flavus interaction. In this study, we compared the miRNA profiles of three maize lines (resistant TZAR102, moderately resistant MI82, and susceptible Va35) at 8 h, 3 d, and 7 d after A. flavus infection to investigate possible regulatory antifungal role of miRNAs. A total of 316 miRNAs (275 known and 41 putative novel) belonging
to 115 miRNA families were identified in response to the fungal infection across all three maize lines. Eighty-two unique miRNAs were significantly differentially expressed with 39 miRNAs exhibiting temporal differential regulation irrespective of the maize genotype, which targeted 544 genes (mRNAs) involved in diverse molecular functions. The two most notable biological processes involved in plant immunity, namely cellular responses to oxidative stress (GO:00345990) and reactive oxygen species (GO:0034614) were significantly enriched in the resistant line TZAR102. Coexpression network analysis identified 34 hubs of miRNA-mRNA pairs where nine hubs had a node in the module connected to their target gene with potentially important roles in resistance/susceptible response of maize to A.
flavus. The miRNA hubs in resistance modules (TZAR102 and MI82) were mostly connected to transcription factors and protein kinases. Specifically, the module of miRNA zma-miR156b-nb – squamosa promoter binding protein (SBP),
zma-miR398a-3p – SKIP5, and zma-miR394a-5p – F-box protein 6 combinations in the resistance-associated modules were considered important candidates for future functional studies.
... To detect aflatoxins, various analytical methods have been developed, including High-Performance Liquid Chromatography (HPLC), Liquid Chromatography-Mass Spectrometry (LC-MS), and Enzyme-Linked Immunosorbent Assay (ELISA) (Yao et al., 2022). While these methods are effective, they often require complex sample preparation and can be time-consuming, which may limit their applicability in rapid screening scenarios (Mitchell et al., 2016;Udomkun et al., 2017). Additionally, they typically involve destructive sampling, which can be a disadvantage in certain contexts where preserving the sample is essential (Chu et al., 2018a;Udomkun et al., 2017;Wang et al., 2010). ...
Fluorescence imaging has developed as a promising non-invasive method for identifying aflatoxin contamination in agricultural commodities, especially corn kernels. This paper examines current improvements in fluorescence imaging technologies, highlighting its potential to improve food safety through swift and precise detection of mycotoxins. The paper examines the basics of fluorescence, the necessary setup for optimal imaging, and the issues related to background fluorescence interference, sensitivity, and the construction of calibration models. Although there are some limitations, fluorescence imaging presents considerable advantages, such as cost-efficiency and the capacity to obtain concurrent spectral and spatial data. Proposed future research objectives include the validation of imaging systems using naturally contaminated samples, the optimization of imaging parameters, and the integration of machine learning techniques to enhance data processing. By overcoming existing constraints and utilizing technical progress, fluorescence imaging can serve as an essential instrument in the detection of aflatoxin contamination, hence enhancing food safety. Keywords: Aflatoxin, Detection, Fluorescence imaging, Food safety, Machine learning.
... Numerous researchers have calculated the annual losses resulting from crop contamination with aflatoxin in different nations. Between USD 20 million and USD 2 billion have been estimated to be lost annually in the United States [9][10][11]. Both Asian and African nations suffer significant losses. ...
Dietary and environmental exposure to aflatoxins via contaminated food items can pose major health challenges to both humans and animals. Studies have reported the coexistence of aflatoxins and other environmental toxins. This emphasizes the urgent need for efficient and effective mitigation strategies for aflatoxins. Previous reports from our laboratory have demonstrated the potency of the green-engineered clays (GECs) on ochratoxin and other toxic chemicals. Therefore, this study sought to investigate the binding and detoxification potential of chlorophyll (CMCH and SMCH) and chlorophyllin (CMCHin and SMCHin)-amended montmorillonite clays for aflatoxin B1 (AFB1). In addition to analyzing binding metrics including affinity, capacity, free energy, and enthalpy, the sorption mechanisms of AFB1 onto the surfaces of engineered clays were also investigated. Computational and experimental studies were performed to validate the efficacy and safety of the clays. CMCH showed the highest binding capacity (Qmax) of 0.43 mol/kg compared to the parent clays CM (0.34 mol/kg) and SM (0.32 mol/kg). Interestingly, there were no significant changes in the binding capacity of the clays at pH2 and pH6, suggesting that the clays can bind to AFB1 throughout the gastrointestinal track. In silico investigations employing molecular dynamics simulations also demonstrated that CMCH enhanced AFB1 binding as compared to parent clay and predicted hydrophobic interactions as the main mode of interaction between the AFB1 and CMCH. This was corroborated by the kinetic results which indicated that the interaction was best defined by chemosorption with favorable thermodynamics and Gibbs free energy (∆G) being negative. In vitro experiments in Hep G2 cells showed that clay treatment mitigated AFB1-induced cytotoxicity, with the exception of 0.5% (w/v) SMCH. Finally, the in vivo results validated the protection of all the clays against AFB1-induced toxicities in Hydra vulgaris. This study showed that these clays significantly detoxified AFB1 (86% to 100%) and provided complete protection at levels as low as 0.1%, suggesting that they may be used as AFB1 binders in feed and food.
... FhpA is necessary for development, aflatoxin production, and stress response in Aspergillus flavus conditions to favor aflatoxin contamination [5]. Unfortunately, underdeveloped or developing countries often lack legislation or resources and technologies needed for stringent enforcement of standards for allowable levels of AFs in agricultural commodities, and thus bear the brunt of adverse health and economic impacts of AF contamination of food and feed commodities. ...
Forkhead transcription factors regulate several important biological processes in many eukaryotic species including fungi. Bioinformatic analysis of the Aspergillus flavus genome revealed four putative forkhead transcription factor genes. Genetic disruption of (AFLA_005634), a homolog of the Aspergillus nidulans fhpA/fkhA gene (AN4521), revealed that the fhpA gene is a negative regulator of both asexual spore production and aflatoxin B1 production in A. flavus. Furthermore, disruption of the fhpA gene caused a complete loss of sclerotial formation. Overexpression of the fhpA gene caused A. flavus to become more sensitive to sodium chloride whereas disruption of the fhpA gene did not change the ability of A. flavus to respond to any osmotic stress agent tested. Interestingly, both disruption and overexpression of the fhpA gene led to increases in sensitivity to the oxidative stress agent menadione. Overall, these results suggest that fhpA is an important regulator of morphological and chemical development in addition to stress response in A. flavus.
... Global annual economic losses due to AF contamination of crops are in the billions of dollars. According to the US FDA (Food and Drug Administration), AF contamination in maize alone may cost the US food industry more than $1 billion each year 30 . Climate change alters the geographic range where crops and foods are susceptible to aflatoxigenic fungal infection to regions outside tropic climes (35 °N to 35 °S), making AF contamination a growing global concern 31 . ...
Essential oils of basil herbs such as nyazbo or sweet basil (Ocimum basilicum), holy basil or tulsi (O. tenuiflorum), and African or clove basil (O. gratissimum) have traditionally been used for their therapeutic potential. These medicinal herbs are being cultivated and consumed globally, and the increasing demand for antimicrobial and antifungal natural products has led to the assessment of the potential of essential oils of medicinal plants to inhibit mycelial growth rather than synthetic fungicides. Thus, the present study explored natural alternatives to inhibit mycelial growth (Aspergilus flavus) and aflatoxin production. Linalool (25.40%), methyl chavicol (37.63%), and eugenol (39.52%) were identified as chief compounds in the EOs of O. basilicum, O. tenuiflorum, and O. gratissimum respectively. Ocimum tenuiflorum EO demonstrated the highest inhibitory activity at 0.75 µL mL− 1 against Aspergillus flavus and totally inhibited the synthesis of aflatoxin B1 (AFB1). The AFB2 production was completely inhibited at 0.25 µL mL− 1 by O. tenuiflorum EO, while O. basilicum and O. gratissimum EOs showed inhibition against AFB2 at 0.50 µL mL− 1, and 1.0 µL mL− 1, respectively. The present study suggests that EOs of basil herbs could be a potential natural alternative of synthetic fungicides to inhibit the fungal growth and aflatoxin production.
... In addition, the distribution of AFB1 contamination in maize was highly uneven and unpredictable, so the batch detection method can only reflect the overall context of the sample, ignoring their individual differences (Stasiewicz et al., 2017). The excessive detection result from batch samples is likely due to the heavy contamination of one single sample, causing the vast majority of uncontaminated maize to be wasted or sold at a discount (Mitchell et al., 2016). lf the percentage of contaminated samples is extremely low, batch testing may fail to detect the contaminated samples, potentially affecting food safety and quality control (Cheng et al., 2019). ...
Aflatoxin B1 (AFB1) is the most widespread, toxic, and harmful mycotoxin, and maize is highly susceptible to AFB1 contamination, posing significant risks to human and animal health. Therefore, precise detection of AFB1 is essential to ensuring food safety. In this study, we used fluorescence probe technology to track the infection process of Aspergillus flavus in maize, confirming the uneven distribution of AFB1 and proposing the use of a “full-surface scanning” spectral information acquisition mode to improve detection accuracy. Therefore, we developed a full-surface fluorescence hyperspectral imaging system with high excitation/emission characteristics, combining dual-wavelength laser-induced fluorescence hyperspectral imaging and data fusion strategy to enable nondestructive detection of AFB1 in individual maize kernels. To address fluorescence crosstalk between maize substance and AFB1, we analyzed three-dimensional fluorescence spectra of healthy maize and pure AFB1 samples, identifying 360 nm and 405 nm as the optimal excitation wavelengths for AFB1 detection in maize. Furthermore, a prediction model for AFB1 content was constructed by combining different levels of data fusion strategies with a partial least squares (PLS) regression algorithm. The results showed that the dual-wavelength data fusion model was superior to the single-wavelength model. Specifically, the decision-level fusion model based on the characteristic wavelength selected by competitive adaptive reweighted sampling (CARS) achieved the best predictive performance (Rp = 0.83). This approach provides a new method for quantitative detection of AFB1 and lays the foundation for the advancement of AFB1 detection technology to enhance food safety.
... [249][250][251] In the US, corn is mainly contaminated by DON and fumonisin B1, and less commonly, aflatoxin (Figure 24.4), depending on environmental conditions of the particular growing season in a state or province. 248,252 In Canada, DON contamination of corn is relatively common in the major corn-producing province of Ontario. 253 The toxins associated with high growing temperatures and drought, aflatoxin B1 ( Figure 24.4), and fumonisin do not occur in Canadian corn. ...
This is a very detailed discussion on fungal metabolites, their measurement and health relevance in homes, non industrial and agriculture & forestry.
... In their study, Mitchell et al. [43] estimated the losses in the US corn industry caused by aflatoxins to be between 0.521-1.68 billion USD. The losses associated with mycotoxins are irreversible. ...
Turkana County, being an arid and semi-arid county is one of the major beneficiaries of the homegrown school feeding program from the government of Kenya. Most of the maize consumed in Turkana county is sourced from other counties as well as neighbouring countries such as Uganda and Ethiopia. Due to the vast distance, high temperatures as well as security challenges, post-harvest losses in the county are inevitable. This study, therefore, sought to establish the losses associated with the quality and safety of maize supplied to public primary schools under the homegrown school feeding program. All suppliers, n=22, who were supplying maize to public primary schools under the homegrown school feeding program, n=128 were included in the study. Maize samples were picked from school stores and analyzed for moisture content, aflatoxin B1, total aflatoxin and fumonisin. Moisture content was determined by AOAC method number AOAC 976.08:2012 while aflatoxin and fumonisin were determined using the ELISA method. Losses were estimated based on the Kenyan standard requirements for maize where any result above the recommended limit was considered a loss. The market price of maize at the time of study, Ksh. 50 per Kg was used to estimate the associated financial losses. The quality losses were Ksh. 15,075,950/= for moisture content and Ksh. 25,805,350/= for grading and live infestation. Safety losses based on aflatoxin B, Total aflatoxin and fumonisin were Ksh. 6,726,850/=, Ksh. 4,362,500/= and Ksh. 1,356,050/=, respectively. In total, Ksh. 53 million would be lost by the county government if the Kenyan standard for maize was well enforced. This shows that the quality and safety of maize supplied to schools under the school meals program is questionable and contributes further to post-harvest losses. Therefore, there is a need for proper sensitization on post-harvest handling among the school suppliers as well as investment in testing infrastructure by the county government. Key words: Feeding, Losses, school, safety, quality, post-harvest, maize, financial, supplied
... In developed nations, extensive testing is performed to exclude AF from the food chain (Krska et al. 2012). In addition to the indirect production costs of AF contamination in the form of testing and mitigation efforts, the direct economic loss in the US may be up to US $1 billion annually (Mitchell et al. 2016). ...
Aflatoxin contamination of corn can occur when developing kernels are infected by the plant pathogen Aspergillus flavus. One route of infection is from airborne conidia. We executed a series of experiments within the corn canopy during two growing seasons and in two states to document the abundance and dynamics of the airborne A. flavus population. We did not observe any significant diurnal changes in the conidial density (p = 0.171) or any effect of sampler height (p = 0.882) within the canopy. Significant changes (p < 0.001) were noted during the season, with a trend towards increased airborne populations with later stages of corn development and more than a 20-fold increase from July to August. The median aflatoxigenicity of airborne isolates from a corn canopy in Texas was about 50 times higher than the corresponding population in Mississippi. It was also noteworthy that highly aflatoxigenic, weakly sporulating S-morphotypes accounted for 14–30% of the airborne isolates in Mississippi at a site with historically rare abundance of S-morphotypes. The genetic diversity was high among the 140 analyzed airborne isolates, with 76 unique haplotypes identified and 55 haplotypes occurring only in 1 isolate. Even in the context of this highly diverse population, a haplotype matching that of a commercial biocontrol strain was found in 13 of the 70 isolates from Mississippi and 1 of the 70 isolates from Texas. The airborne A. flavus population is genetically diverse (Shannon’s index = 1.4 to 1.6), similar to grain samples in other surveys, and much less aflatoxigenic in Mississippi than in Texas.
... The European Union has set even lower limits of 2 ng/g (equivalent to parts per billion, ppb) for aflatoxin B1 in cereals, dried fruits, and tree nuts, and 5 ng/g of aflatoxin B1 in maize and rice that must undergo sorting or other physical treatment before being placed on the market. However, such regulations may negatively impact the economies of countries relying on maize and peanut imports or exports [5,9,10]. ...
Maize is one of the major crops that are susceptible to Aspergillus flavus infection and subsequent aflatoxin contamination, which poses a serious health threat to humans and domestic animals. Here, an RNA interference (RNAi) approach called Host-Induced Gene Silencing (HIGS) was employed to suppress the O-methyl transferase gene (omtA, also called aflP), a key gene involved in aflatoxin biosynthesis. An RNAi vector carrying part of the omtA gene was introduced into the B104 maize line. Among the six transformation events that were positive for containing the omtA transgene, OmtA-6 and OmtA-10 were self-pollinated from T1 to T4, and OmtA-7 and OmtA-12 to the T6 generation. These four lines showed at least an 81.3% reduction in aflatoxin accumulation at the T3 generation under laboratory conditions. When screened under field conditions with artificial inoculation, OmtA-7 at T5 and T6 generations and OmtA-10 at T4 generation showed a reduction in aflatoxin contamination between 60% and 91% (p < 0.02 to p < 0.002). In order to develop commercial maize lines with enhanced aflatoxin resistance, the omtA transgene in OmtA-7 was introduced into three elite inbred lines through crossing, and the resulting crosses also exhibited significantly lower aflatoxin accumulation compared to crosses with non-transgenic controls (p < 0.04). In addition, high levels of omtA-specific small RNAs were only detected in the transgenic kernel and leaf tissues. These results demonstrate that suppression of omtA through HIGS can enhance maize resistance to aflatoxin contamination, and this resistance can be transferred to elite backgrounds, providing a viable and practical approach to reduce aflatoxin contamination in maize.
... AFB 1 , being exceptionally toxic, also demonstrates the highest levels of contamination among mycotoxins [15]. Exposure to AF has been strongly linked to a heightened risk of developing growth impairment, hepatocellular carcinoma (HCC), HIV/AIDs, and under nourishment among children across continents such as America, Asia, and Africa [16][17][18][19][20][21][22][23][24]. There are many stages in the food chain where agricultural contamination can arise, typically emerging in crops before harvest or during extended periods(pre-and post-harvesting) of crop storage [25]. ...
Aflatoxins (AFs), produced by fungi, are highly hazardous and classified as mycotoxins. Controlling their levels is of significant concern. This group consists of 20 fungal metabolites, all structurally derived from difuranocoumarin. Exposure to AFs through food can cause critical health issues, such as cancers, deformities, and mutations, posing a significant global public health issue. The inherent dangers of AF exposure necessitate swift and reliable detection techniques to identify its presence in food products. The rise of nanotechnology has opened doors to innovative electrochemical biosensors, offering a promising solution to this pressing issue. This review delves into nanomaterial-based aptasensors, immunosensors, and molecularly imprinted polymers, the predominant electrochemical biosensors developed for AF detection. This paper offers a broad summary of recent advancements in biosensor technology in electrochemical sensing of AFs, alongside challenges to overcome limitations, and future perspectives.
Graphical Abstract
... For example, the plant pathogens Apiospora arundinis, Fusarium annulatum, F. luffae, Penicillium brevicompactum, P. glabrum, and Hypoxylon investiens were some of the most common taxa in our study and can devastate certain crops. Aflatoxin contamination of maize crops from fungal growth is estimated to cost somewhere between $52.1 million to $1.68 billion annually in the US alone (Mitchell et al. 2016); thus, understanding routes of contamination is critical in developing effective ways to mitigate the spread (Khlangwiset and Wu 2010) since bats transport Aspergillus and Penicillium species. Likewise, Fusarium also costs billions a year in the US (Wilson et al. 2018). ...
Bats (Chiroptera), the second largest group of mammals, are known for their unique immune system and their ability to act as vectors for various zoonoses. Bats also act as important carriers of fungi, which include plant, animal, and human pathogens. Their roosting areas, foraging behaviors, and even migration routes make bats ideal vectors for fungi. We isolated 75 culturable fungal species from bats in Yunnan Province, China, with 36 species representing known pathogens of plants, animals, and humans, while 39 species are non-pathogenic fungi. Among these species, 77% (58 species) belonged to Ascomycota, 9% (seven species) belonged to Basidiomycota, and 13% (10 species) belonged to Mucoromycota. Even though several taxonomic studies on fungi associated with bats have been published, studies exploring the role of bats as fungal vectors are lacking. This study discusses the fungi host-specific traits and pathogenicity and the impact and ecological significance of bats as fungal vectors.
... The elimination of these substances from food is difficult because of their chemical characteristics, which confer resistance to the processing stages [4]. In the United States, annual losses in maize production due to AFL contamination alone are estimated to be USD 52.1 million to USD 1.68 billion [5]. For these reasons, several countries have legislated and enforced maximum levels of mycotoxins in certain grains, determining the limits allowed in products destined for animal consumption (Table 1). ...
Approximately 25% of cereal grains present with contamination caused by fungi and the presence of mycotoxins that may cause severe adverse effects when consumed. Maize has been genetically engineered to present different traits, such as fungal or insect resistance and herbicide tolerance. This systematic review compared the observable quantities, via meta-analysis, of four mycotoxins (aflatoxins—AFL, fumonisins—FUM, deoxynivalenol—DON, zearalenone—ZEA) between genetically modified (GM) and conventional maize kernels. This study was conducted following the PRISMA guidelines, with searches performed using PubMed, Web of Science, Scopus, Google Scholar, and CAPES journals databases. Analyses were conducted using RevMan v.5.4 software. Transgenic maize showed a 58% reduction in total mycotoxins (p < 0.001) compared to conventional maize. FUM were the most impacted, with a 59% reduction (p < 0.001) in GM maize. AFL and ZEA levels were also lower in GM maize by 49% (p = 0.02) and 51% (p < 0.001), respectively. On the other hand, DON levels increased by 6% (p < 0.001) in GM maize compared to conventional maize. However, results for ZEA and DON were inconclusive due to the limited research and sample sizes. We conclude that transgenic maize reduces total mycotoxins by over 50%, primarily fumonisin and aflatoxin. Most studies presented maize varieties that were resistant to insects or herbicides, not fungal pathogens, showing a positive collateral effect of these genetic alterations. Therefore, transgenic maize appears to be a safer product for animal and human consumption from a toxicological point of view. Further studies with larger sample sizes are needed to confirm our findings for ZEA and DON in transgenic maize.
... However, dried fruits have been a particular focus of aflatoxin regulations worldwide since the drying and preserving process promotes the growth of a fungus, which contains aflatoxins. On the other hand, many of the Sub-Saharan, African, Middle Eastern and Asian countries are also known to be exposed to high humidity, warm temperatures, and drought which are also associated with high levels of aflatoxins (MITCHELL et al., 2016). Clearly, given their poor capacity to ensure food safety, low-income countries lag behind evolving standards (higher safety norms) imposed by industrialised countries. ...
Increased concerns on food contaminants draw special attention to food safety regulations. These regulations may have direct impact on food trade. The aim of the paper is to assess the impact of regulations concerning aflatoxin maximum residue limits (MRL) on dried fruits trade. The empirical method we adopt combines both gravity and welfare methodologies in a partial equilibrium context.
... Among food and feed safety concerns, mycotoxins are rated the highest chronic health risk for feed products (Battilani & Leggieri, 2015;Kuiper-Goodman, 2004). Mycotoxin detection and mitigation are estimated at $418-$1.66 billion annually in the United States, equaling a large percentage of food and feed safety issues' overall economic impact (Mitchell et al., 2016;Vardon et al., 2003;Wu, 2006). Along with a significant economic impact, aflatoxin (AFL) prevalence rates are anticipated to increase in future years (Mitchell human food and animal feeds (corn and other grains) for immature animals or unknown destinations of AFL (FDA, 2019). ...
Mycotoxins are secondary metabolites produced by fungi found in corn and are anticipated to increase globally due to enhanced weather extremes and climate change. Aflatoxin (AFL) is of concern due to its harmful effects on human and animal health. AFL can move through complex grain supply chains in the United States, including multiple stakeholders from farms, grain elevators, grain and ethanol processors, and feed mills, before reaching end users, putting numerous entities at risk. Since corn is an essential food and feed product, risk management of AFL must be considered. This case study aimed to (1) calculate the probabilities of pivotal events with AFL in corn at Food Safety Modernization Act‐regulated entities using an event tree analysis (ETA) and (2) propose recommendations based on factors identified through the ETA for AFL risk management. The ETA was based on historical AFL prevalence data in Iowa above a 20‐part per billion (ppb) threshold (2.30%). Results showed four single‐point failures in feed safety systems, where countermeasures did not function as designed. Failure is defined as the type 2 error of corn being infected with AFL <20 ppb, when it is >20 ppb, and the overall system fails to detect this with contaminated corn reaching end users. The success rate is defined as detecting the corn samples correctly >20 ppb. The average success rate was 50.14%, and the failure rate was 49.86%. It was concluded that risk‐informed decisions are a critical component of effective AFL monitoring in corn, with timely intervention strategies needed to minimize the overall effects on end users.
... ose a risk to the consumer and some studied samples were heavily contaminated with aflatoxins at levels higher than the limits prescribed by European Union (EU) regulations (4 μg/kg) (EU, 2010). The implications of aflatoxins go beyond the public health aspect but also commercial and economic ramifications(Belasli et al. 2023;Ben Miri et al. 2023).Mitchell et al. (2016) estimate that aflatoxin contamination could result in losses to the cereal industry up to US$1.68 billion per year in the United States (U.S.) due to climate change. Camel feed from different regions of Saudi Arabia were collected and screened for the presence of fungi and mycotoxins (Bokhari 2010). Authors concluded that feed samples u ...
The 2020 world population data sheet indicates that world population is projected to increase from 7.8 billion in 2020 to 9.9 billion by 2050 (Increase of more than 25%). Due to the expected growth in human population, the demand for meats that could improve health status and provide therapeutic benefits is also projected to rise. The dromedary also known as the Arabian camel, or one-humped camel (Camelus dromedarius), a pseudo ruminant adapted to arid climates, has physiological, biological and metabolic characteristics which give it a legendary reputation for surviving in the extreme conditions of desert environments considered restrictive for other ruminants. Camel meat is an ethnic food consumed across the arid regions of Middle East, NorthEast Africa, Australia and China. For these medicinal and nutritional benefits, camel meat can be a great option for sustainable meat worldwide supply. A considerable amount of literature has been published on technological aspects and quality properties of beef, lamb and pork but the information available on the technological aspects of the meat of the one humped camel is very limited. Camels are usually raised in less developed countries and their meat is as nutritionally good as any other traditional meat source. Its quality also depends on the breed, sex, age, breeding conditions and type of muscle consumed. A compilation of existing literature related to new technological advances in packaging, shelf-life and quality of camel meat has not been reviewed to the best of our knowledge. Therefore, this review attempts to explore the Open Peer Review Approval Status 1 2 version 3 (revision)
... Among these species, A. flavus is considered the most problematic because it infects major crops such as corn, cotton, peanuts, and tree nuts worldwide and contaminates them with AFB1 [2]. AF contamination not only harms humans and livestock, but also causes significant economic losses due to the disposal of contaminated agricultural products [3]. A. flavus resides in agricultural soil in its habitat, is carried by wind or insects to attach to crops, proliferates during crop storage, and accumulates AFB1 [4]. ...
Aspergillus flavus produces aflatoxin, a carcinogenic fungal toxin that poses a threat to the agricultural and food industries. There is a concern that the distribution of aflatoxin-producing A. flavus is expanding in Japan due to climate change, and it is necessary to understand what types of strains inhabit. In this study, we sequenced the genomes of four Aspergillus strains isolated from agricultural fields in the Ibaraki prefecture of Japan and identified their genetic variants. Phylogenetic analysis based on single-nucleotide variants revealed that the two aflatoxin-producing strains were closely related to A. flavus NRRL3357, whereas the two non-producing strains were closely related to the RIB40 strain of Aspergillus oryzae, a fungus widely used in the Japanese fermentation industry. A detailed analysis of the variants in the aflatoxin biosynthetic gene cluster showed that the two aflatoxin-producing strains belonged to different morphotype lineages. RT-qPCR results indicated that the expression of aflatoxin biosynthetic genes was consistent with aflatoxin production in the two aflatoxin-producing strains, whereas the two non-producing strains expressed most of the aflatoxin biosynthetic genes, unlike common knowledge in A. oryzae, suggesting that the lack of aflatoxin production was attributed to genes outside of the aflatoxin biosynthetic gene cluster in these strains.
... Surprisingly, aflatoxin has even been detected in pasteurized ultra-high temperature milk, broiler chicken meat, eggs, and sausage (Siddappa et al., 2012;Shaltout et al., 2014). Although the financial impact of aflatoxin contamination in animal feeds is not specifically determined in India, the U.S. corn industry in the southern region experiences considerable annual losses estimated at US$ 1.68 billion due to climatic conditions (Mitchell et al., 2016). The presence of aflatoxin and ochratoxin, natural contaminants commonly found in animal feeds, can have a significant negative impact on animal production, leading to substantial economic losses (Battacone et al., 2010). ...
Aflatoxin being a serious threat to public health and international trade, necessi-tates a comprehensive understanding and calculated response with effective inter-vention strategies. This review methodically looks at several aspects of aflatoxin, starting with how it affects international trade laws through feed and feed ingre-dient regulations. Aflatoxin contamination poses serious challenges to world health and the economy, especially in areas that are already at risk. Examining the varia-bles affecting aflatoxin toxicity, the paper clarifies aflatoxin toxicity's complex me-tabolism and the resulting health effects of exposure. The serious repercussions of aflatoxicosis outbreaks and their connections to illnesses like Aspergillosis and cancer are highlighted by a detailed exploration of prospective decontamination techniques as well as strategies for detecting and capturing aflatoxin. A thorough knowledge of the factors that contribute to aflatoxin contamination demonstrates the intricate interactions between environmental variables, farming methods, stor-age circumstances, and different physical, biological, and nutritional components. Strong detection strategies are required due to aflatoxins’ significant effects on an-imal and human health. The paper describes complete preventative tactics that en-compass manipulation in management strategies. global trade and public health from this pervasive threat.
... (Yu & Cleveland, 2007). The structural genes that are responsible for coding for these enzymes are grouped together in a cluster, and their expression is arranged by two regulatory genes (aflS and aflR) (Mitchell et al., 2016). In applying PCR for the detection of AF-producing strains, some studies targeted seven genes (Abd El-Aziz et al., 2021;Fakruddin et al., 2015), four genes (Hassan, 2023) or three genes (Mahmoud, 2015;Sohrabi & Taghizadeh, 2018). ...
Spices are food flavouring agents that are highly used in Iraq. However, they may be contaminated by toxicogenic fungi and subsequent production of mycotoxins. The aim of this study was to investigate the contamination of commonly used spices with fungi using polymerase chain reaction (PCR) assay and to detect fungal mycotoxin using high‐performance liquid chromatography. Thirty‐five spices (seven samples from each black pepper, red pepper, turmeric, cumin and ginger) were cultured on an appropriate medium to identify various fungi species. Later on, the toxigenicity of Aspergillus flavus and Aspergillus niger was determined using a PCR assay. The fungal mycotoxins, including aflatoxins and ochratoxins, were then determined through a high‐performance liquid chromatography using the validated Quick, Easy, Cheap, Effective, Rugged, and Safe (QuECHERS) method. Aspergillus species were the predominantly isolated fungi, followed by Penicillium and Fusarium . The PCR results indicate the high toxigenicity of A. flavus as 85.7% of the strains had aflQ / aflR genes and 79% had PKS15KS / PKS15C‐MeT genes. Regarding mycotoxin contamination in spices, the highest rates of aflatoxins and ochratoxins were found in black pepper (5.913 μg/kg) and red chilli (6.9055 μg/kg), respectively. Spices are susceptible substrates for the growth of mycotoxigenic fungi. Thus, regular effective surveillance and quality control procedures are highly recommended.
... This is due to the need to test crops for mycotoxins to comply with regulations, the losses of contaminated batches, damage to the reputation of companies or exporting countries [29], reduced food production, the cost associated with treating animal mycotoxicosis, and even the loss of animals due to illness [30]. For instance, in the USA, aflatoxin contamination in corn is estimated to result in losses ranging from USD 52.1 million to USD 1.68 billion annually [31]. ...
Food-producing animals are exposed to mycotoxins through ingestion, inhalation, or dermal contact with contaminated materials. This exposure can lead to serious consequences for animal health, affects the cost and quality of livestock production, and can even impact human health through foods of animal origin. Therefore, controlling mycotoxin exposure in animals is of utmost importance. A systematic literature search was conducted in this study to retrieve the results of monitoring exposure to mycotoxins in food-producing animals over the last five years (2019–2023), considering both external exposure (analysis of feed) and internal exposure (analysis of biomarkers in biological matrices). The most commonly used analytical technique for both approaches is LC-MS/MS due to its capability for multidetection. Several mycotoxins, especially those that are regulated (ochratoxin A, zearalenone, deoxynivalenol, aflatoxins, fumonisins, T-2, and HT-2), along with some emerging mycotoxins (sterigmatocystin, nivalenol, beauvericin, enniantins among others), were studied in 13,818 feed samples worldwide and were typically detected at low levels, although they occasionally exceeded regulatory levels. The occurrence of multiple exposure is widespread. Regarding animal biomonitoring, the primary objective of the studies retrieved was to study mycotoxin metabolism after toxin administration. Some compounds have been suggested as biomarkers of exposure in the plasma, urine, and feces of animal species such as pigs and poultry. However, further research is required, including many other mycotoxins and animal species, such as cattle and sheep.
... [249][250][251] In the US, corn is mainly contaminated by DON and fumonisin B1, and less commonly, aflatoxin (Figure 24.4), depending on environmental conditions of the particular growing season in a state or province. 248,252 In Canada, DON contamination of corn is relatively common in the major corn-producing province of Ontario. 253 The toxins associated with high growing temperatures and drought, aflatoxin B1 ( Figure 24.4), and fumonisin do not occur in Canadian corn. ...
Fungal metabolites and allergens, chemistry, mechanistic information, measurement and relevance in non-industrial workplaces including schools as well as homes and in agriculture
The Aspergillus flavus expression database (AFED) is a comprehensive resource dedicated to exploring gene expression in A. flavus, a significant fungal pathogen that threatens food security by contaminating crops with aflatoxin. Given the complex regulation of aflatoxin biosynthesis and the lack of centralized expression data resources for this important pathogen, a database integrating diverse experimental conditions is essential for understanding its biology and developing control strategies. Public RNA sequencing data were used to quantify gene expression abundance for 604 A. flavus samples from 52 experiments. Using abundance data, we created an AFED accessible through a web-based interface that allows for the expression profiles of genes to be conveniently examined across different growth conditions and life cycle stages. Expression profiles can be visualized through either an interactive bar plot for single gene queries or a heatmap for multiple gene queries. A gene co-expression network based on samples containing at least 10 million mapped reads is also available, which allows users to identify genes that are co-expressed with an individual gene or set of genes and displays the functional enrichment among the co-expressed genes.
Database URL: https://a-flavus-expression-db-jyqnpeuvta-uc.a.run.app
Citrinin (CTN) is a mycotoxin that adversely affects livestock by contaminating stored grains, leading to significant health and economic impacts. This study investigates the toxicological effects of CTN on porcine small intestinal epithelial cells (IPEC-J2) and explores potential mitigation strategies using natural products and chemical inhibitors. Our study demonstrates that CTN induces cytotoxicity through the TGF-β signaling pathway, triggering apoptosis and G2/M phase cell cycle arrest. We examined cell viability, cell cycle progression, and gene expression changes in IPEC-J2 cells treated with CTN, 4′-Hydroxydehydrokawain (4-HDK), and LY-364947, a TGF-β receptor inhibitor. LY-364947 treatment confirmed that CTN-induced toxicity is mediated through TGF-β signaling. Although 4-HDK alleviated CTN-induced cytotoxicity by improving cell viability and reducing apoptosis, its direct involvement in TGF-β inhibition remains unclear. These results suggest that CTN disrupts intestinal epithelial cell homeostasis via TGF-β activation, whereas 4-HDK may exert protective effects through an alternative mechanism. Our study provides novel insights into CTN-induced toxicity mechanisms and highlights the therapeutic potential of 4-HDK as a mitigator of mycotoxin-induced cellular damage.
Globally, aflatoxin contamination in maize remains a huge burden despite many interventions put in place. The use of low-temperature plasma to decontaminate the maize is a potential solution for ensuring the safety and extended shelf life of the grain. This study optimized the parameters and investigated the efficacy of low-temperature nitrogen plasma (LTNP) in destroying fungi and reducing exposure to aflatoxins in naturally contaminated maize from an endemic region. The study generated 17 experimental runs using the Response Surface Methodology (RSM) of the Box Behnken Design (BBD) with exposure time, pressure, and ionization density as independent variables. Quantitative exposure assessment was conducted using Monte Carlo simulations followed by sensitivity and scenario analysis to study factors influencing exposure and best aflatoxin-reducing plasma parameters. The best-fitting RSM model, the linear model, indicated that increased exposure time but not pressure and power led to a corresponding statistically significant decrease in the fungal load and aflatoxin content. LTNP reduced aflatoxin contamination to levels below all the main global regulatory limits. Numerical optimization of the percent reduction in aflatoxin and fungal load indicated that an exposure time of 1793.4 s, pressure of 0.98 pascal and ionization power of 189.8 W are required to achieve an optimal reduction of aflatoxin content of 82.6% and fungal load of 96.9%. Exposure assessment indicated high exposure especially for populations with lower body weight with ρ = -0.46 between body weight and exposure. The best LTNP combinations achieved aflatoxin exposure reduction results comparable to but with markedly less variation than existing practically used decontamination methods. Further optimization studies during upscaling are recommended, incorporating independent factors such as temperature and processing volume and outcomes such as organoleptic, physical, and chemical changes in the food matrices after treatment.
Aflatoxin B1 (AFB1) is a highly carcinogenic substance primarily produced by Aspergillus flavus and Aspergillus parasiticus . Sterigmatocystin (ST), a precursor of aflatoxin, is mainly produced by Aspergillus nidulans and Aspergillus creber . Both mycotoxins have similar biosynthetic pathways and structural characteristics, yet ST is considered to be less carcinogenic than AFB1. The scope of this study is to investigate how environmental conditions such as pH, temperature, and oxygen levels influence the production of toxins by good AFB1 producer Aspergillus flavus Zt41 (isolated from corn in Hungary) and ST hyper‐producer Aspergillus creber 2663 (isolated from a flour mill in Hungary) on rice substrate. Temperature played a significant role in mycotoxin production, particularly in the production of sterigmatocystin, which peaked at 26°C with 392 μg/g, which was 3–4 times higher than amounts measured for 18°C, 22°C, and 30°C in the presence of oxygen. Oxygen availability was crucial for both growth and toxin production, as anaerobic conditions significantly impeded these processes. The rice substrate effectively served as a buffer, significantly reducing the impact of pH changes caused by citrate buffers. This is the first detailed study on the effects of pH, temperature, and oxygen availability on ST production of the hyper‐producer Aspergillus creber strain isolated from a flour mill in Hungary.
Aflatoxins are carcinogenic and mutagenic mycotoxins that contaminate food and feed. The objective of our research is to predict aflatoxin outbreaks in Texas-grown maize using dynamic geospatial data from remote sensing satellites, soil properties data, and meteorological data by an ensemble of models. We developed three model pipelines: two included mechanistic models that use weekly aflatoxin risk indexes (ARIs) as inputs, and one included a weather-centric model; all three models incorporated soil properties as inputs. For the mechanistic-dependent models, ARIs were weighted based on a maize phenological model that used satellite-acquired normalized difference vegetation index (NDVI) data to predict maize planting dates for each growing season on a county basis. For aflatoxin outbreak predictions, we trained, tested and validated gradient boosting and neural network models using inputs of ARIs or weather, soil properties, and county geodynamic latitude and longitude references. Our findings indicated that between the two ARI-mechanistic models evaluated (AFLA-MAIZE or Ratkowsky), the best performing was the Ratkowsky-ARI neural network (nnet) model, with an accuracy of 73%, sensitivity of 71% and specificity of 74%. Texas has significant geographical variability in ARI and ARI-hotspot responses due to the diversity of agroecological zones (hot-dry, hot-humid, mixed-dry and mixed-humid) that result in a wide variation of maize growth and development. Our Ratkowsky-ARI nnet model identified a positive correlation between aflatoxin outbreaks and prevalence of ARI hot-spots in the hot-humid areas of Texas. In these areas, temperature, precipitation and relative humidity in March and October were positively correlated with high aflatoxin contamination events. We found a positive correlation between aflatoxin outbreaks and soil pH in hot-dry and hot-humid regions and minimum saturated hydraulic conductivity in mixed-dry regions. Conversely, there was a negative relationship between aflatoxin outbreaks and maximum soil organic matter (hot-dry region), and calcium carbonate (hot-dry, and mixed-dry). It is likely soil fungal communities are more diverse, and plants are healthier in soils with high organic matter content, thereby reducing the risk of aflatoxin outbreaks. Our results demonstrate that intricate relationships between soil hydrological parameters, fungal communities and plant health should be carefully considered by Texas corn growers for aflatoxin mitigation strategies.
Aspergillus flavus and the produced aflatoxins cause great damage to crop production, food security, and human health. The control of A. flavus and aflatoxins in the grains during storage is a great challenge to humans worldwide. In this study, we investigated the potential of the strain TR-18, isolated from the rhizosphere of tea plants, in controlling A. flavus and aflatoxins. The results demonstrated that TR-18 greatly inhibited A. flavus growth in dual cultural tests by the production of antifungal volatiles. TR-18 was identified as Flavobacterium johnsoniae through biochemical analysis and a 16S rRNA phylogenetic tree. Moreover, TR-18 effectively inhibited A. flavus growth and aflatoxin production in peanuts during storage. Further analysis of TR-18’s volatiles was conducted by gas chromatography–tandem mass spectrometry. Five authentic compounds were identified in the volatiles of TR-18: methyl thiolacetate, dimethyl disulfide (DMDS), methyl isovalerate, 5-methyl-3-hexanone, and S-methyl 3-methylbutanethioate. DMDS with a relative content of 54.92% (peak area normalization) was the most abundant compound in the volatiles. The minimal inhibitory concentration of DMDS against A. flavus growth was 50 μl/liter (compound volume/airspace volume). The other compounds also showed a great inhibition rate (more than 90%) to A. flavus at 200 μl/liter. In addition, TR-18 exhibited broad antifungal activity against other six important phytopathogens, that is, Fusarium graminearum, F. verticillioides, Colletotrichum graminicola, C. fructicola, Alternaria alternata, and Botrytis cinerea, with inhibition rates ranging from 52.90 to 98.70%. In conclusion, F. johnsoniae TR-18 with the production of five types of antifungal volatiles could be used as potential biocontrol agents in controlling pathogenic fungi and associated mycotoxins in the grains during storage.
Insect infestation and microbial, particularly mold contamination, are the major causes of stored grain deterioration during postharvest storage, which results in a significant loss in grain quality and quantity, and the formation of toxic chemicals such as mycotoxins. Pesticides, together with physical protection strategies, have been widely used to control insects and molds in stored grains, but their uses present significant environmental and health problems. This has led to the exploration of safer pesticide alternatives. Essential oils (EOs) are highly concentrated materials extracted from leaves, stems, flowers, seeds, roots, fruit rinds, resins, or barks. They are multifunctional due to their complex chemical composition. Thus, EOs are frequently used for their therapeutic, antimicrobial, odoriferous, and flavor properties in a wide range of products like medicine, cosmetics, and foods. This review provides comprehensive information on the chemical compositions of EOs commonly used in the food industry, factors influencing EO composition, and recent studies on the potential of EOs as alternatives to synthetic pesticides and fungicides for stored grain protection. The relationship between chemical compositions of EOs and their anti-insects and antimicrobial potentials, as well as current approaches/technologies of using EOs for food preservation, are also covered. However, this review also highlights the need for research on the development of feasible and affordable methodologies to apply effective EOs or encapsulated EOs in grain storage settings, particularly for organic grain protection.
This chapter addresses mold and dampness in the built environment and mycotoxin exposure in developing countries.
Aflatoxin B1 (AFB1) is a class 1 carcinogen and mycotoxin known to contribute to the development of hepatocellular carcinoma (HCC), growth impairment, altered immune system modulation, and malnutrition. AFB1 is synthesized by Aspergillus flavus and is known to widely contaminate foodstuffs, particularly maize, wheat, and groundnuts. The mechanism in which AFB1 causes genetic mutations has been well studied, however its metabolomic effects remained largely unknown. A better understanding of how AFB1 disrupts metabolism would provide insight into how this mycotoxin leads to carcinogenesis, growth impairment, and/or immunomodulation, and may reveal potential targets for pharmacological or nutritional interventions to protect against these effects. The current study evaluated the metabolomic effects of various doses (2.5 μM, 5 μM, 10uM) of AFB1 treatment to HepG2 (liver), MDA-MB-231 (breast), and A549 (lung) cells. Treated and control cells’ metabolomic profiles were evaluated via ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS). Univariate and multivariate analyses revealed significant alterations in metabolite concentrations from each dose of AFB1 treatment in each cell type. Pathway analysis was then used to understand broader biochemical functions affected by AFB1 treatment in each cell type. HepG2 cell pathway analyses revealed significant pathway perturbations in lipid metabolism, carnitine synthesis, catecholamine biosynthesis, purine metabolism, and spermidine and spermine biosynthesis. Analysis of A549 cells found a greater emphasis of perturbations on various amino acids along with lipid synthesis-related pathways, and catecholamine biosynthesis. Finally, analysis of treated MDA-MB-231 cells found spermidine and spermine biosynthesis, carnitine synthesis, plasma membrane-related pathways (phosphatidylcholine synthesis and alpha linolenic acid and linoleic acid metabolism), and various amino acid metabolism pathways to be most affected. These highlighted pathways should be targeted in future investigations to evaluate their potential in mitigating or preventing the development of negative health effects associated with AFB1 exposure.
Aflatoxin B1 (AFB1) and fumonisin B1 (FB1) are toxic secondary products of fungi that frequently contaminate staple crops in resource-limited settings. Antenatal AFB1 and FB1 exposure may cause adverse birth outcomes. We conducted a retrospective substudy nested in a case-control cohort of HIV-infected and HIV-uninfected women ≥20 weeks gestation from Harare, Zimbabwe. Urinary aflatoxin M1 (AFM1) and FB1, biomarkers of AFB1 and FB1 exposure, respectively, were quantified in random antenatal urine via ELISA and grouped into tertiles. The adverse birth outcomes considered were low birth weight, preterm birth (PTB), small for gestational age, stillbirth, birth defects, neonatal death, neonatal jaundice and perinatal death (PD). We evaluated any associations between adverse birth outcomes and exposure to AFB1, FB1, or the AFB1-FB1 combination via a multivariable logistic regression controlled for potential confounders. We enrolled 94 HIV-infected and 81 HIV-uninfected women. In HIV-infected, AFM1 was detected in 46/94 (49%), and FB1 was detected in 86/94 (91%). In HIV-uninfected, AFM1 was detected in 48/81 (59%), and FB1 was detected in 74/81 (91%). Among all women, AFM1 tertile 3 was associated with PD (OR: 6.95; 95% CI: 1.21-39.78). In the same population, AFM1 tertiles 2 (OR: 13.46; 95% CI: 1.20-150.11) and 3 (OR: 7.92; 95% CI: 1.08-58.19) were associated with PTB. In HIV-infected, AFM1 tertile 2 was associated with PTB (OR: 64.73; 95% CI: 2.37-177.93). Our results revealed an association between AFB1 exposure and PD and PTB in women, including those infected with HIV. Public health and nutrition measures are necessary to mitigate mycotoxins.
Aflatoxins (AFs) are secondary fungal metabolites that contaminate common food crops and are harmful to humans and animals. The ability to degrade or remove aflatoxins from common feed commodities will improve health standards and counter the economic drain inflicted by AF contamination. Bioremediation is a promising solution to AF contamination because of its low cost and few undesired environmental side-effects. Identifying new degrader species is highly beneficial in that it can offer alternatives to overcome the limitations of existing biodegraders, such as narrow working conditions and low degradation rates. Here, we screen several environmental isolates for their AF detoxification ability, using aflatoxin G2. We use different carbon sources (glucose and starch) in isolation and culturing media to examine the effect of the environment on degradation ability. Strains isolated in media with starch as the primary carbon source showed a higher percentage of good AF degraders, 16% compared to 2% when glucose was the primary carbon source. Additionally, the majority of species isolated in glucose medium exhibited improved degradation efficiency when moved into starch medium, with one isolate improving degradation levels from 30 to 70%. Our starch screen also revealed three previously unidentified AF degrader bacterial species. Good aflatoxin G2 degraders also appear to perform well against aflatoxin B1. Overall, for AF degradation, starch medium expedites the screening process and generally improves the performance of isolates. We thus propose that using starch as the carbon source is a promising means to identify new AF degraders in the environment.
The human immunodeficiency virus (HIV) heavily affects women from resource-limited settings who are vulnerable to potentially harmful mycotoxins including aflatoxin B1 (AFB1), fumonisin B1 (FB1) and ochratoxin A (OTA). We aimed to conduct biomonitoring and ascertain the determinants of maternal mycotoxin exposure in pregnancy, lactation and post-lactation periods. We conducted a retrospective longitudinal study in HIV-infected and HIV-uninfected women from Harare, Zimbabwe. 175 and 125 random urine samples in pregnancy and 24 months after delivery (post-lactation) respectively were analysed for aflatoxin M1 (AFM1) and FB1 by ELISA. 6 weeks after delivery (lactation), 226 and 262 breast milk (BM) samples were analysed for AFM1 and OTA respectively by ELISA. The association of demographics and food consumption with mycotoxins was evaluated using multivariable logistic regression. In HIV-infected, urinary AFM1 was detected in 46/94 (Median: 0.05; Range: 0.04-0.46 ng mL-1) in pregnancy and 47/66 (Median: 0.05; Range: 0.04-1.01 ng mL-1) post-lactation. Urinary FB1 was detected in 86/94 (Median: 1.39; Range: 0.17-6.02 ng mL-1) in pregnancy and 56/66 (Median: 0.72; Range: 0.20-3.81 ng mL-1) post-lactation. BM AFM1 was detected in 28/110 (Median: 7.24; Range: 5.96-29.80 pg mL-1) and OTA in 11/129 (Median: 0.20; Range: 0.14-0.65 ng mL-1). In HIV-uninfected, urinary AFM1 was detected in 48/81 (Median: 0.05; Range: 0.04-1.06 ng mL-1) in pregnancy and 41/59 (Median: 0.05; Range: 0.04-0.52 ng mL-1) post-lactation. Urinary FB1 was detected in 74/81 (Median: 1.15; Range: 0.17-6.16 ng mL-1) in pregnancy and 55/59 (Median: 0.96; Range: 0.20-2.82 ng mL-1) post-lactation. BM AFM1 was detected in 38/116 (Median: 7.70; Range: 6.07-31.75 pg mL-1) and OTA in 4/133 (Median: 0.24; Range: 0.18-0.83 ng mL-1). Location, wealth, and peanut butter consumption were determinants of AFB1 exposure. HIV infection, BMI, location, rainy season, unemployment, and age were determinants of FB1 exposure. Women especially those pregnant and/or HIV-infected are at risk of adverse effects of mycotoxins.
In Sub-Saharan Africa, cereals are threatened by stress-inducing microbial pathogens and parasites such as fungi, bacteria, viruses and nematodes leading to significant losses. Mycotoxin-producing fungi like Fusarium graminearum induce head blight disease causing 30–70% of yield losses in wheat. In comparison, Fusarium verticillioides accounts for ear rot diseases that account for 13–70% of maize yield losses in Sub-Saharan Africa. Outbreaks of the devastating rice blast pathogen Magnaporthe oryzae have caused up to 48% yield losses of rice in Kenya. The grey leaf spot fungus, C. zeina, gradually becomes a threat to maize production, causing a 65% yield loss in South Africa. Maize smut and ergot-causing pathogens, Sporisorium ehrenbergii and Claviceps africana, under mildly humid and cold climatic conditions, impact grain quality and market value. The maize streak virus predominantly ravages maize fields all over Sub-Saharan Africa causing 30–100% yield losses while the diseases caused by the bacterium Xanthomonas oryzae pv. oryzae has led to 10 to 50% yield losses in rice production. In Nigeria, nematode pathogens like Pratylenchus spp have been reported to cause yield losses of up to 27% in maize production. This review fundamentally discusses these cereal pathogens and their current and future impact in the face of climate change in Africa. We seriously emphasize the need for more simulation studies on each of these pathogens across Sub-Saharan Africa and their potential impact under current and future climate change scenarios.
Crops contamination with aflatoxins (AFs) and zearalenone (ZEA) threaten human and animal health; these mycotoxins are produced by several species of Aspergillus and Fusarium. The objective was to evaluate under field conditions the influence of the wet season on the dissemination of AF- and ZEA-producing fungi via houseflies collected from dairy farms. Ten dairy farms distributed in the semi-arid Central Mexican Plateau were selected. Flies were collected in wet and dry seasons at seven points on each farm using entomological traps. Fungi were isolated from fly carcasses via direct seeding with serial dilutions and wet chamber methods. The production of AFs and ZEA from pure isolates was quantified using indirect competitive ELISA. A total of 693 Aspergillus spp. and 1274 Fusarium spp. isolates were obtained, of which 58.6% produced AFs and 50.0% produced ZEA (491 ± 122; 2521 ± 1295 µg/kg). Houseflies and both fungal genera were invariably present, but compared to the dry season, there was a higher abundance of flies as well as AF- and ZEA-producing fungi in the wet season (p < 0.001; 45.3/231 flies/trap; 8.6/29.6% contaminated flies). These results suggest that rainy-weather conditions on dairy farms increase the spread of AF- and ZEA-producing Aspergillus spp. and Fusarium spp. through houseflies and the incorporation of their mycotoxins into the food chain.
To ensure future food security, it is crucial to understand how potential climate change scenarios will affect agriculture. One key area of interest is how climatic factors, both in the near- and the long-term future, could affect fungal infection of crops and mycotoxin production by these fungi. The objective of this paper is to review the potential impact of climate change on three important mycotoxins that contaminate maize in the United States, and to highlight key research questions and approaches for understanding this impact. Recent climate change analyses that pertain to agriculture and in particular to mycotoxigenic fungi are discussed, with respect to the climatic factors – temperature and relative humidity – at which they thrive and cause severe damage. Additionally, we discuss how climate change will likely alter the life cycles and geographic distribution of insects that are known to facilitate fungal infection of crops.
Adherence to regulatory limits for mycotoxins in agricultural commodities is important to safeguard consumers and to permit trade in affected commodities across international borders. Reliable estimates of mycotoxin concentrations are required to implement regulatory decisions on the suitability of lots of produce for consumption or trade. Effective schemes to test for mycotoxins depend not only upon sound analytical methods, but also on well designed and implemented sampling plans. This manual provides information to food analysts and regulatory officials on effective sampling plans to detect mycotoxins in food. The concepts of uncertainty and variability in mycotoxin test procedures are discussed as well as the importance of ensuring that samples are representative of the lot being sampled, and the consequences of a poorly designed sampling plan on the reliability of the measured levels of mycotoxins, possibly resulting in legal disputes and barriers to trade.
Aspergillus flavus has received a considerable amount of attention due to its ability to produce aflatoxin, a secondary metabolite that is both immunosuppressive and carcinogenic to animals and humans. Research on aflatoxin over the last 40 years has made it one of the best studied fungal secondary metabolites. In spite of the large volume of research in this area, many unanswered questions remain concerning the genetic regulation of aflatoxin production and the molecular signals that intimately associate the synthesis of aflatoxin with specific environmental and nutritional conditions. It is anticipated that the tools now available in the field of genomics will build upon our existing knowledge and provide answers to some of these questions. Complete genome sequences are now available for a number of fungal species that are closely related to A. flavus. This information can be used along with current genomic analyses in A. flavus to more closely examine the biosynthesis and regulation of secondary metabolism. The intent of this review is to summarize the large body of knowledge that exists from many years of research on A. flavus, with the hope that this information in the light of new genomic studies may bring scientists closer to unraveling the web of regulatory circuits that govern aflatoxin biosynthesis. Specifically, scientific findings in the following areas will be presented: classification and phylogenetic analyses of A. flavus, population biology, ecology and pathogenicity in agricultural environments , classical genetics including linkage group and mutant analyses, gene clusters, regulation of aflatoxin biosynthesis, and genomics.
Aflatoxins, fungal toxins produced by Aspergillus flavus and Aspergillus parasiticus in a variety of food crops, are well known as potent human hepatocarcinogens. Relatively less highlighted in the literature is the association between aflatoxin and growth impairment in children. Foodborne aflatoxin exposure, especially through maize and groundnuts, is common in much of Africa and Asia--areas where childhood stunting and underweight are also common, due to a variety of possibly interacting factors such as enteric diseases, socioeconomic status, and suboptimal nutrition. The effects of aflatoxin on growth impairment in animals and human children are reviewed, including studies that assess aflatoxin exposure in utero and through breastfeeding. Childhood weaning diets in various regions of the world are briefly discussed. This review suggests that aflatoxin exposure and its association with growth impairment in children could contribute a significant public health burden in less developed countries.
Hepatocellular carcinoma (HCC), or liver cancer, is the third leading cause of cancer deaths worldwide, with prevalence 16-32 times higher in developing countries than in developed countries. Aflatoxin, a contaminant produced by the fungi Aspergillus flavus and Aspergillus parasiticus in maize and nuts, is a known human liver carcinogen.
We sought to determine the global burden of HCC attributable to aflatoxin exposure.
We conducted a quantitative cancer risk assessment, for which we collected global data on food-borne aflatoxin levels, consumption of aflatoxin-contaminated foods, and hepatitis B virus (HBV) prevalence. We calculated the cancer potency of aflatoxin for HBV-postive and HBV-negative individuals, as well as the uncertainty in all variables, to estimate the global burden of aflatoxin-related HCC.
Of the 550,000-600,000 new HCC cases worldwide each year, about 25,200-155,000 may be attributable to aflatoxin exposure. Most cases occur in sub-Saharan Africa, Southeast Asia, and China where populations suffer from both high HBV prevalence and largely uncontrolled aflatoxin exposure in food.
Aflatoxin may play a causative role in 4.6-28.2% of all global HCC cases.
Both aflatoxin and the human immunodeficiency virus (HIV) cause immune suppression and millions of HIV-infected people in developing countries are chronically exposed to aflatoxin in their diets. We investigated the possible interaction of aflatoxin and HIV on immune suppression by comparing immune parameters in 116 HIV positive and 80 aged-matched HIV negative Ghanaians with high (> or =0.91 pmol/mg albumin) and low (<0.91 pmol/mg albumin) aflatoxin B1 albumin adduct (AF-ALB) levels. AF-ALB levels and HIV viral load were measured in plasma and the percentages of leukocyte immunophenotypes and cytokine expression were determined using flow cytometry. The cross-sectional comparisons found that (1) among both HIV positive and negative participants, high AF-ALB was associated with lower perforin expression on CD8+ T-cells (P = .012); (2) HIV positive participants with high AF-ALB had significantly lower percentages of CD4+ T regulatory cells (Tregs; P = .009) and naive CD4+ T cells (P = .029) compared to HIV positive participants with low AF-ALB; and (3) HIV positive participants with high AF-ALB had a significantly reduced percentage of B-cells (P = .03) compared to those with low AF-ALB. High AF-ALB appeared to accentuate some HIV associated changes in T-cell phenotypes and in B-cells in HIV positive participants.
The variability associated with testing lots of shelled corn for aflatoxin was investigated. Eighteen lots of shelled corn were tested for aflatoxin contamination. The total variance associated with testing shelled corn was estimated and partitioned into sampling, sample preparation, and analytical variances. All variances increased as aflatoxin concentration increased. With the use of regression analysis, mathematical expressions were developed to model the relationship between aflatoxin concentration and the total, sampling, sample preparation, and analytical variances. The expressions for these relationships were used to estimate the variance for any sample size, subsample size, and number of analyses for a specific aflatoxin concentration. Test results on a lot with 20 parts per billion aflatoxin using a 1.13 kg sample, a Romer mill, 50 g subsamples, and liquid chromatographic analysis showed that the total, sampling, sample preparation, and analytical variances were 274.9 (CV = 82.9%), 214.0 (CV = 73.1 %), 56.3 (CV = 37.5%), and 4.6 (CV = 10.7%), respectively. The percentage of the total variance for sampling, sample preparation, and analytical was 77.8, 20.5, and 1.7, respectively.
Fetal and early childhood environment, including the
nutritional status of the pregnant mother and the
infant, are considered critical for growth and risk of
disease in later life. Many people in developing coun
tries are not only malnourished but also chronically
exposed to high levels of toxic fungal metabolites
(mycotoxins). One family of mycotoxins, the aflatoxins,
are carcinogenic and immunotoxic and cause growth
retardation in animals. Aflatoxins contaminate staple
foods in West Africa, particularly maize and ground
nuts, as a result of hot, humid storage conditions that
promote fungal growth. High exposure to aflatoxins
occurs throughout childhood in the region, suggest
ing that growth and development could be critically
affected.We assessed exposure to aflatoxins in relation
to anthropometric measures in children in Benin and
Togo.
Aflatoxins are well recognized as a cause of liver cancer, but they have additional important toxic effects. In farm and laboratory animals, chronic exposure to aflatoxins compromises immunity and interferes with protein metabolism and multiple micronutrients that are critical to health. These effects have not been widely studied in humans, but the available information indicates that at least some of the effects observed in animals also occur in humans. The prevalence and level of human exposure to aflatoxins on a global scale have been reviewed, and the resulting conclusion was that approximately 4.5 billion persons living in developing countries are chronically exposed to largely uncontrolled amounts of the toxin. A limited amount of information shows that, at least in those locations where it has been studied, the existing aflatoxin exposure results in changes in nutrition and immunity. The aflatoxin exposure and the toxic affects of aflatoxins on immunity and nutrition combine to negatively affect health factors (including HIV infection) that account for >40% of the burden of disease in developing countries where a short lifespan is prevalent. Food systems and economics render developed-country approaches to the management of aflatoxins impractical in developing-country settings, but the strategy of using food additives to protect farm animals from the toxin may also provide effective and economical new approaches to protecting human populations.
Although aflatoxins (AFs) have been shown to be immune-suppressive agents in animals, the potential role of AFs in modifying the distribution and function of leukocyte subsets in humans has never been assessed. We examined the cellular immune status of 64 Ghanaians in relation to levels of aflatoxin B1 (AFB1)-albumin adducts in plasma. The percentages of leukocyte immunophenotypes in peripheral blood, CD4+ T cell proliferative response, CD4+ T(h) and CD8+ T cell cytokine profiles and monocyte phagocytic activity were measured using flow cytometry. NK cell cytotoxic function was determined by perforin and tumor necrosis factor-alpha expression in CD3-CD56+ NK cells. AFB1-albumin adducts levels ranged from 0.3325 to 2.2703 (mean = 0.9972 +/- 0.40, median = 0.9068) pmol mg(-1) albumin. Study participants with high AFB1 levels had significantly lower percentages of CD3+ and CD19+ cells that showed the CD69+ activation marker (CD3+CD69+ and CD19+CD69+) than participants with low AFB1 levels (P = 0.002 for both). Also, the percentages of CD8+ T cells that contained perforin or both perforin and granzyme A were significantly lower in participants with high AFB1 levels compared with those with low AFB1 (P = 0.012 for both). Low levels of CD3+CD69+ (r = -0.32, P = 0.016) and CD19+CD69+ (r = -0.334, P = 0.010) cells were significantly associated with high AFB1 levels using correlation analysis. By multivariate analysis, there were strong negative correlations between the percentages of these cells (CD3+CD69+: b = -0.574, P = 0.001, and CD19+CD69+: b = -0.330, P = 0.032) and AFB1 levels. These alterations in immunological parameters in participants with high AFB1 levels could result in impairments in cellular immunity that could decrease host resistance to infections.
In April 2004, one of the largest aflatoxicosis outbreaks occurred in rural Kenya, resulting in 317 cases and 125 deaths. Aflatoxin-contaminated homegrown maize was the source of the outbreak, but the extent of regional contamination and status of maize in commercial markets (market maize) were unknown. We conducted a cross-sectional survey to assess the extent of market maize contamination and evaluate the relationship between market maize aflatoxin and the aflatoxicosis outbreak. We surveyed 65 markets and 243 maize vendors and collected 350 maize products in the most affected districts. Fifty-five percent of maize products had aflatoxin levels greater than the Kenyan regulatory limit of 20 ppb, 35% had levels > 100 ppb, and 7% had levels > 1,000 ppb. Makueni, the district with the most aflatoxicosis case-patients, had significantly higher market maize aflatoxin than did Thika, the study district with fewest case-patients (geometric mean aflatoxin = 52.91 ppb vs. 7.52 ppb, p = 0.0004). Maize obtained from local farms in the affected area was significantly more likely to have aflatoxin levels > 20 ppb compared with maize bought from other regions of Kenya or other countries (odds ratio = 2.71; 95% confidence interval, 1.12-6.59). Contaminated homegrown maize bought from local farms in the affected area entered the distribution system, resulting in widespread aflatoxin contamination of market maize. Contaminated market maize, purchased by farmers after their homegrown supplies are exhausted, may represent a source of continued exposure to aflatoxin. Efforts to successfully interrupt exposure to aflatoxin during an outbreak must consider the potential role of the market system in sustaining exposure.
Myotis sodalis), including its selection of and use of hibernacula, roost trees, and foraging habitat. An extensive list of published references related to the Indiana bat is included. The Authors MICHAEL A. MENZEL and JOHN W. EDWARDS are wildlife biologists with West Virginia University's Division of Forestry at Morgantown. JENNIFER M. MENZEL and W. MARK FORD are research wildlife biologists with the Northeastern Research Station in Parsons. TIMOTHY C. CARTER is a wildlife biologist with Southern Illinois University's Department of Zoology at Carbondale. Manuscript received for publication 24 May 2001 Contents
Because of the variability among laboratory sample test results, two types of mistakes are associated with any mycotoxin-sampling plan. First, good lots (lots with a concentration less than or equal to the legal limit) will test bad and be rejected by the sampling plan. The chances of making this type of mistake is often called the seller’s risk (false positives or type I, α error) since these lots will be rejected at an unnecessary cost to the seller of the product. Secondly, bad lots (lots with a concentration greater than the legal limit) will test good and be accepted by the sampling program. The chances of making this type of mistake is called the buyer’s risk (false negatives, or type II, β error) since contaminated lots will be processed into feed or food causing possible health problems and/or economic loss to the buyer of the product.
Mycotoxins are toxic metabolites produced by fungal species that commonly contaminate staple foods and feeds. They represent an unavoidable problem due to their presence in globally consumed cereals such as rice, maize and wheat. Most mycotoxins are immunosuppressive agents and some are carcinogens, hepatotoxins, nephrotoxins, and neurotoxins. Worldwide trends envision a stricter control of mycotoxins, however, the changing global environment may not be the ideal setting to control and reduce the exposure to these toxins. Although new technologies allow us to inspect the multi-mycotoxin presence in foods, new sources of exposure, gaps in knowledge of mycotoxins interactions, appearance of "emergent" mycotoxins and elucidation of consequent health effects can complicate their control even more. While humans are adapting to cope with environmental changes, such as food scarcity, decreased food quality, mycotoxin regulations, crop production and seasonality, and other climate related modifications, fungal species are also adapting and increased cases of mycotoxin adverse health effects are likely to occur in the future. To guarantee access to quality food for all, we need a way to balance global mycotoxin standards with the realistic feasibility of reaching them, considering limitations of producers and designing strategies to reduce mycotoxin exposure based on sound research.
Insect damage, Aspergillus flavus Link infection, and aflatoxin contamination are recurring problems in preharvest corn (Zea mays L.) in the Coastal Plain of Georgia. A 6-yr study (1977-1982) over a 46-county area revealed that insect damage ranged from a mean of 1.7 cm per ear in 1979 to 4.0 cm per ear in 1977. The incidence of aflatoxin contamination in grain samples ranged from 57% in 1982 to 100% in 1980. The highest concentration of aflatoxin (4708 μg kg-1 was recorded in a field sample collected in 1977. The action level set by the Food and Drug Administration for aflatoxin is 20 μg kg-1. Insect damage contributed significantly to enhanced A. flavus sporulation and aflatoxin contamination. Levels of aflatoxin were positively correlated with temperature and total net evaporation. The occurrence of undamaged, uncontaminated corn in the Coastal Plain during a majority of the years suggests that crop management, including hybrid selection, planting date, and irrigation, may have a significant influence on the quantity of quality corn grain produced.
Aflatoxin B1 is a potent hepatacarcinogen that occurs in corn worldwide. The aflatoxin‐producing fungus Aspergillus flavus can grow and produce aflatoxin on corn preharvest and in storage. Within the U.S., aflatoxin contamination of preharvest corn has been reported in 23 states, and contamination is chronic in the southeastern U.S. where hot, drought conditions often favor the fungus and the production of aflatoxin. Management practices have been developed to reduce aflatoxin contamination, but in years when environmental conditions are extremely favorable for the fungus, no control strategy is effective. Resistance to aflatoxin accumulation appears to be heritable, but no commercial hybrids are available with adequate resistance. This review covers the epidemiology of A. flavus in preharvest corn from the infection process to the factors that influence aflatoxin formation. Also discussed are the problems associated with the development of resistant varieties and new strategies that are being developed for control of aflatoxin contamination.
Use of proper sampling methods throughout the agri-food chain is crucial when it comes to effectively detecting contaminants in foods and feeds. The objective of the study was to estimate the performance of sampling plan designs to determine aflatoxin B(1) (AFB(1)) contamination in corn fields. A total of 840 ears were selected from a corn field suspected of being contaminated with aflatoxin. The mean and variance among the aflatoxin values for each ear were 10.6 mug/kg and 2233.3, respectively. The variability and confidence intervals associated with sample means of a given size could be predicted using an equation associated with the normal distribution. Sample sizes of 248 and 674 ears would be required to estimate the true field concentration of 10.6 mug/kg within +/-50 and +/-30%, respectively. Using the distribution information from the study, operating characteristic curves were developed to show the performance of various sampling plan designs.
The aim of this study was to examine the exposure of lactating mothers to aflatoxins using aflatoxin M(1) in breast milk as a biomarker for exposure and to detect its determining factors and possible effects on child growth. A 9% sample of 2022 lactating women who exclusively breastfed their infants, including 91 lactating women of urban areas of Tabriz city and 91 lactating women of its rural areas were recruited by a geographical clustered sampling method. Breast milk samples and information on food intake were collected from subjects using structured food-frequency questionnaire. Extraction of AFM(1) was performed with the ELISA test procedure. Aflatoxin M(1) was detected in breast milk of 20 out of 91 mothers (22%) in concentrations of 6.96 +/- 0.94 (pg/ml) in rural areas. Aflatoxin M(1) contamination was not present in samples of urban areas. The presence of aflatoxin M(1) was significantly associated with consumption of local milk (beta = 0.71, P < 0.001) and stunted growth in children (beta = -0.31, P < 0.015). These findings emphasize the need for developing strategies to reduce exposure to aflatoxin, possibly involving interventions targeted at reducing contamination of foods.
It is difficult to obtain precise and accurate estimates of the true mycotoxin concentration of a bulk lot when using a mycotoxin-sampling plan that measures the concentration in a small portion of the bulk lot. A mycotoxin-sampling plan is defined by a mycotoxin test procedure and a defined accept/reject limit. A mycotoxin test procedure is a complicated process and generally consists of several steps: (a) a sample is taken from the lot, (b) the sample is ground (comminuted) in a mill to reduce particle size, (c) a subsample is removed from the comminuted sample, and (d) the mycotoxin is extracted from the comminuted subsample and quantified. Even when using accepted test procedures, there is variability associated with each step of the mycotoxin test procedure. Because of this variability, the true mycotoxin concentration in the lot cannot be determined with 100% certainty by measuring the mycotoxin concentration in a sample taken from the lot. The variability for each step of the mycotoxin test procedure, as measured by the variance statistic, is shown to increase with mycotoxin concentration. Sampling is usually the largest source of variability associated with the mycotoxin test procedure. Sampling variability is large because a small percentage of kernels are contaminated and the level of contamination on a single seed can be very large. Methods to reduce sampling, sample preparation, and analytical variability are discussed.
Aflatoxins are potent mycotoxins that cause developmental and immune system suppression, cancer, and death. As a result of regulations intended to reduce human exposure, crop contamination with aflatoxins causes significant economic loss for producers, marketers, and processors of diverse susceptible crops. Aflatoxin contamination occurs when specific fungi in the genus Aspergillus infect crops. Many industries frequently affected by aflatoxin contamination know from experience and anecdote that fluctuations in climate impact the extent of contamination. Climate influences contamination, in part, by direct effects on the causative fungi. As climate shifts, so do the complex communities of aflatoxin-producing fungi. This includes changes in the quantity of aflatoxin-producers in the environment and alterations to fungal community structure. Fluctuations in climate also influence predisposition of hosts to contamination by altering crop development and by affecting insects that create wounds on which aflatoxin-producers proliferate. Aflatoxin contamination is prevalent both in warm humid climates and in irrigated hot deserts. In temperate regions, contamination may be severe during drought. The contamination process is frequently broken down into two phases with the first phase occurring on the developing crop and the second phase affecting the crop after maturation. Rain and temperature influence the phases differently with dry, hot conditions favoring the first and warm, wet conditions favoring the second. Contamination varies with climate both temporally and spatially. Geostatistics and multiple regression analyses have shed light on influences of weather on contamination. Geostatistical analyses have been used to identify recurrent contamination patterns and to match these with environmental variables. In the process environmental conditions with the greatest impact on contamination are identified. Likewise, multiple regression analyses allow ranking of environmental variables based on relative influence on contamination. Understanding the impact of climate may allow development of improved management procedures, better allocation of monitoring efforts, and adjustment of agronomic practices in anticipation of global climate change.
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