Aflatoxin Management Research Articles

우간다옥수수의 아플라톡신 오염 실태 조사 분석 및 대책 연구

Aflatoxins are highly toxic and carcinogenic compounds produced by the fungi, Aspergillus flavus and Aspergilus parasticus during growth on crops such as maize. Because of high temperature and humidity as in Uganda, Fungus infection increased in maize therefore more aflatoxin produced. Aflatoxin contamination makes a serious problem of food safety issue. Also contaminated product lower their marketability and productivity, finally reduce incomes of household. To solce this problem Uganda would like to develop fungus-resistant variety and post-harvesting technique.This study practiced survey the aflatoxin levels in Uganda maize farm and food market before research as developing new methods for reducing Aflatoxin. We collected 55 samples through domestic and survey aflatoxin contamination. About 11 % of samples were contaminated and is contents ranges 12.7-123.5mg/Kg.In addition , 9 % of samples exceed regulation limit.These results mean the management of aflatoxin must be proceed by developing new fungus-resistant variety, dry and storage technique.

Seasonal variation of aflatoxin M1 in raw milk from the Yangtze River Delta region of China

The objective of this study was to evaluate the occurrence of aflatoxin M1 (AFM1) in raw milk samples from 18 dairy farms in the Yangtze River Delta region during four different seasons. A total of 72 tank milk samples was collected with 18 samples for each season. Milk AFM1 was detected using LC-MS/MS. The AFM1 was detected in 43 milk samples (59.7%) ranging in concentration from 10 to 420 ng/L. The concentration of AFM1 in raw milk was significantly higher during the winter (123 ng/L) than during other seasons (P < 0.05). There was no significant difference between the spring (29.1 ng/L), summer (31.9 ng/L), and autumn (31.6 ng/L) (P > 0.05) seasons. This indicates that raw milk collected during the winter is at high risk for AFM1 and that seasonal factors should be considered for the management of aflatoxins in both the feed and milk.

Influence of plant host species on intraspecific competition during infection by Aspergillus flavus

Compositions of Aspergillus flavus populations determine the extent to which crops become contaminated with aflatoxins. In the current study, influences of diverse crop hosts on competition among A. flavus isolates were quantified with pyrosequencing. Maize, cotton, soyabean and sorghum supported different levels of sporulation, but intraspecific differences in sporulation were not detected on any host. However, hosts differentially influenced competition during infection, allowing greater sporulation by some isolates and increased host tissue invasion by others. Furthermore, competitive interactions during host invasion did not predict isolate success during sporulation. Isolates were similarly competitive on maize and sorghum, the two most closely related hosts. Host‐specific influences on intraspecific competition may dictate compositions of A. flavus populations and, as a result, the severity of aflatoxin contamination. Host factors should be considered when designing and implementing aflatoxin management strategies including biocontrol with atoxigenic strains.

An integrated approach for the reduction of aflatoxin contamination in chilli (Capsicum annuum L.).

An integrated approach for management of aflatoxin contamination in chilli was undertaken by evaluating the fungicides, bioagents and plant extracts against Aspergillus flavus under both in vitro and field condition. Maximum inhibition of radial growth (91.1%) was observed with 0.3% mancozeb followed by captan (85.2%). Carbendazim (73%) was effective and superior over other systemic fungicides. A complete inhibition (100%) of A. flavus was observed in neem seed kernel extract (NSKE), nimbicidin and pongamia oil at 5%. An indigenous Pseudomonas fluorescens bioagent isolate inhibited (74.9%) the growth of A. flavus over Trichoderma harzianum (70.4%). The superior performing fungicides, plant extracts and bioagents identified under in vitro were used for challenge inoculation on chilli fruits and so also for field evaluation. The captan treated fruits recorded the least infection of A. flavus (1.6%) followed by P. fluorescens (2.0%), NSKE (2.2%) and nimbicidin treated fruits (7.8%) as against control (38.3%). As regards to field evaluation, the least incidence was recorded in NSKE sprayed chilli plot (1.6%) and was on par with captan (2.2%), P. fluorescens (2.4%) and T. harzianum (2.6%) compared to control (7.4%). Hence, a pre-harvest spray of NSKE (5%) or mancozeb (0.3%) or P. fluorescens (1 × 10(8)cfu/ml) 10days before harvest of chilli is recommended for field level management of aflatoxin.

Identification of Atoxigenic Aspergillus flavus Isolates to Reduce Aflatoxin Contamination of Maize in Kenya.

Aspergillus flavus has two morphotypes, the S strain and the L strain, that differ in aflatoxin-producing ability and other characteristics. Fungal communities on maize dominated by the S strain of A. flavus have repeatedly been associated with acute aflatoxin poisonings in Kenya, where management tools to reduce aflatoxin levels in maize are needed urgently. A. flavus isolates (n = 290) originating from maize produced in Kenya and belonging to the L strain morphotype were tested for aflatoxin-producing potential. A total of 96 atoxigenic isolates was identified from four provinces sampled. The 96 atoxigenic isolates were placed into 53 vegetative compatibility groups (VCGs) through complementation of nitrate non-utilizing mutants. Isolates from each of 11 VCGs were obtained from more than one maize sample, isolates from 10 of the VCGs were detected in multiple districts, and isolates of four VCGs were found in multiple provinces. Atoxigenic isolates were tested for potential to reduce aflatoxin concentrations in viable maize kernels that were co-inoculated with highly toxigenic S strain isolates. The 12 most effective isolates reduced aflatoxin levels by >80%. Reductions in aflatoxin levels caused by the most effective Kenyan isolates were comparable with those achieved with a United States isolate (NRRL-21882) used commercially for aflatoxin management. This study identified atoxigenic isolates of A. flavus with potential value for biological control within highly toxic Aspergillus communities associated with maize production in Kenya. These atoxigenic isolates have potential value in mitigating aflatoxin outbreaks in Kenya, and should be evaluated under field conditions.

Farmers’ perceptions, knowledge and management of aflatoxins in groundnuts ( Arachis hypogaea L.) in India

Aflatoxins, produced by the fungi Aspergillus flavus Link ex Fries and Aspergillus parasiticus Speare, are the major toxins affecting the quality of groundnuts ( Arachis hypogaea L.) meant for human consumption. Groundnuts can be infected with aflatoxin-producing fungi pre-harvest, at harvest and post-harvest. This survey was conducted in Gujarat province in India in order to assess farmers’ and other stakeholders’ (extension staff and traders) perceptions and knowledge of aflatoxin contamination of groundnuts and to evaluate the agronomic and market practices used to manage it. The survey investigated the effects of the socioeconomic background of the farmers. The results showed that the socioeconomic and psychological characteristics, viz. education, caste, farm size, social participation, extension participation, market orientation, economic motivation, innovativeness and perception had positive and significant associations with farmers’ knowledge. The extension staff and traders had a good understanding of the problem and of the importance of managing aflatoxin contamination but farmers did not. Farmers’ who practised effective crop husbandry in order to increase production were unwittingly managing aflatoxin contamination to some extent. Their marketing practises showed that the problem of aflatoxin contamination was neglected at both the production and marketing stages. We suggest that extension agencies need to train farmers in the use of biological control agents, post-harvest management and identification of aflatoxin contamination. Partnerships need to be forged between research institutions, the departments of agriculture of various states, marketing agencies, NGOs, farmers’ groups, consumer groups, agrochemical manufacturers and other stakeholders in order to develop strategies for addressing the problem of aflatoxin contamination.

Assessment of Adoption Gaps in Management of Aflatoxin Contamination of Groundnut (Arachis Hypogaea L.)

One of the major impediments for diversification of groundnut (Arachis Hypogaea L.) as food crop is aflatoxin contamination. The study was conducted with an objective to assess the adoption gaps in aflatoxin management practices of groundnut (AMPG) and the farmer's characteristics influencing these gaps. The study used an expost-facto research design and multi-stage random sampling. The data were collected from 180 respondents through interview schedule. For measuring adoption gap, knowledge of AMPG and perception of groundnut quality suitable scales were developed. The data were subjected to multiple regression analysis to know the characteristics, which influenced the adoption gaps in AMPG. The majority of farmers were in high adoption gap category, as most of the farmers had not adopted the harvest and post-harvest management practices. Farmers' characteristics such as knowledge, market orientation and innovativeness influenced the adoption gap significantly. These three variables put together explained 58% of variation in adoption gap. Based on the results, it is suggested to formulate strategies to increase the knowledge of farmers through various extension approaches. If the knowledge on AMPG is improved the adoption gaps can be reduced. The maiden research effort, shed light on the socio-economic dimensions of aflatoxin contamination and constraints for aflatoxin management at farmers' level. The study has significance for the policy makers, extension departments and groundnut farmers for production of quality groundnut.

Molecular characterization of atoxigenic strains for biological control of aflatoxins in Nigeria

Aflatoxins are highly toxic carcinogens produced by several species in Aspergillus section Flavi. Strains of A. flavus that do not produce aflatoxins, called atoxigenic strains, have been used commercially in North America as tools for limiting aflatoxin contamination. A similar aflatoxin management strategy is being pursued in Nigeria. In the current study, loci across the 68 kb aflatoxin biosynthesis gene cluster were compared among 18 atoxigenic and two aflatoxin-producing vegetative compatibility groups (VCGs) from Nigeria and an atoxigenic VCG used commercially in North America. Five of the atoxigenic VCGs had large deletions (37–65 kb) extending from the teleomeric side of the aflatoxin biosynthesis cluster. In one VCG (AV0222) the deletion extended through the cluster to the adjacent sugar cluster. The remaining twelve atoxigenic VCGs, including the VCG used for aflatoxin management in North America, contained all the aflatoxin pathway genes, but with defects. Two observations support the long-term persistence of atoxigenicity within A. flavus: first, a comparison of pathway genes revealed more changes in atoxigenic than in aflatoxin-producing isolates relative to the aflatoxin-producing strain NRRL 3357; and second, several non-synonymous changes are unique to atoxigenics. Atoxigenic VCG diversity was assessed with phylogenetic analyses. Although some atoxigenics share relatively recent ancestry, several are more closely related to aflatoxin producers than to other atoxigenics. The current study demonstrates VCGs of A. flavus in West Africa with diverse mechanisms of atoxigenicity and potential value in aflatoxin management programmes.

Factors influencing the adoption of aflatoxin management practices in groundnut (Arachis hypogaea L.)

Groundnut (Arachis hypogaea L.) is a major oilseed crop of India. Groundnut has great potential for diversification, from oil extraction to food uses, due to its high nutritive value. Aflatoxin contamination is the major impediment to such diversification. Aflatoxins, produced by the fungi Aspergillus flavus and A. parasiticus, are the major toxins affecting the quality of groundnut meant for human consumption. The adoption of ‘Aflatoxin Management Practices of Groundnut’ (AMPG) is very important for reducing aflatoxin contamination. This study was undertaken with the aims of determining the extent of adoption of AMPG by farmers, to assess the constraints upon adoption of AMPG and to understand the relationship between adoption of AMPG by farmers and socio-economic and psychological factors. The results indicated that the majority of the farmers were unaware of aflatoxin contamination and hence had not adopted sowing, post-sowing and post-harvest aflatoxin management practices. The farmers with large land holdings were high adopters of AMPG compared to farmers with small land holdings. Socio-economic and psychological characteristics such as innovativeness, perception of groundnut quality, extension participation, socio-economic status, market orientation and farm size significantly influenced the adoption of AMPG. Mass awareness campaigns need to be organized to improve the stakeholders' perception of groundnut quality and the ill-effects of consuming aflatoxin-contaminated products.

Impact ofAspergillussectionFlavicommunity structure on the development of lethal levels of aflatoxins in Kenyan maize (Zea mays)

To evaluate the potential role of fungal community structure in predisposing Kenyan maize to severe aflatoxin contamination by contrasting aflatoxin-producing fungi resident in the region with repeated outbreaks of lethal aflatoxicosis to those in regions without a history of aflatoxicosis. Fungi belonging to Aspergillus section Flavi were isolated from maize samples from three Kenyan provinces between 2004 and 2006. Frequencies of identified strains and aflatoxin-producing abilities were assessed, and the data were analysed by statistical means. Most aflatoxin-producing fungi belonged to Aspergillus flavus. The two major morphotypes of A. flavus varied greatly between provinces, with the S strain dominant in both soil and maize within aflatoxicosis outbreak regions and the L strain dominant in nonoutbreak regions. Aspergillus community structure is an important factor in the development of aflatoxins in maize in Kenya and, as such, is a major contributor to the development of aflatoxicosis in the Eastern Province. Since 1982, deaths caused by aflatoxin-contaminated maize have repeatedly occurred in the Eastern Province of Kenya. The current study characterized an unusual fungal community structure associated with the lethal contamination events. The results will be helpful in developing aflatoxin management practices to prevent future outbreaks in Kenya.

Strategies in Prevention of Preharvest Aflatoxin Contamination in Peanuts: Aflatoxin Biosynthesis, Genetics and Genomics

Abstract Peanut (Arachis hypogaea L.), or groundnut, is an important crop economically and nutritionally in many tropical and subtropical areas of the world. It is also one of the most susceptible host crops to Aspergillus flavus resulting in aflatoxin contamination. The prevention or elimination of aflatoxin contamination in preharvest and postharvest crops is a serious challenge facing scientists. The recent International Conference on Groundnut Aflatoxin Management and Genomics held in Guangzhou, China, provided an international forum for discussions on the latest accomplishments, the development of strategies, and the initiation of cooperative research for the prevention of aflatoxin contamination. This review summarizes the progress in genetic and genomic research of peanuts and the toxin-producing fungus A. flavus. In particular, the pathway for production and the genetic regulation of afaltoxin, and the peanut-Aspergillus interaction are discussed. The use of a peanut-Aspergillus microarray will help scientists to study the crop-pathogen interaction; aids in the identification of genes involved in both fungal invasion and crop resistance, and ultimately enhance research to find solutions that prevent aflatoxin contamination in agricultural commodities.

Breeding Peanut for Resistance to Aflatoxin Contamination at ICRISAT

Abstract Peanut plays an important role in the livelihoods of poor farmers and in the rural economy of many developing countries. Aflatoxin contamination in peanut seeds, caused by Aspergillus flavus, hampers international trade and adversely affects health of consumers of peanut and its products. It can occur in the field when the crop is growing, during harvesting and curing, and in storage and transportation. Aflatoxin research on peanut at ICRISAT focuses on identification and utilization of genetic resistance to preharvest seed infection and aflatoxin production by A. flavus and pre and post harvest management practices to minimize contamination. Breeding for aflatoxin resistance has been a contentious issue in peanut for nearly four decades since the first report of host resistance to aflatoxin production by A. flavus. Despite global efforts, progress in aflatoxin resistance breeding has been limited due to the low level of resistance to different components of resistance (preharvest seed infection and aflatoxin production, and in vitro seed colonization by A. flavus), their variable performance due to high G × E interaction, lack of reliable screening protocols, and limited understanding of genetics of resistance. Efforts to combine the three independently inherited components of resistance did not produce expected results towards improving the host plant resistance to aflatoxin contamination. Although breeding lines have shown better performance for resistance to aflatoxin contamination at ICRISAT, they need wider evaluation under diverse growing conditions. The search for better sources of resistance in the cultivated and wild Arachis germplasm continues, and recent developments in the area of transgenic research through modification of aflatoxin biosynthesis pathway or use of genes with antifungal and anti-aflatoxin properties appear encouraging. Meanwhile, the available improved breeding lines coupled with pre and post harvest aflatoxin management practices can help to significantly reduce aflatoxin contamination in farmers' fields. It is expected that transgenic resistance against fungal infection and aflatoxin production in combination with conventional breeding efforts may lead to the development of agronomically superior peanuts that are free of aflatoxin contamination.

Peanut Aflatoxin and Genomics Research in China: Progress and Perspectives

Abstract Peanut is an important oil and food crop in China with a unique role in agricultural development and food security. Aflatoxin contamination in peanut, normally more serious in southern parts of the country, is a crucial factor affecting sustainable development of the peanut industry. Extensive efforts have been made at several institutions in China for aflatoxin management and related genomics research. Several local peanut germplasm lines have been identified as resistant to seed infection by Aspergillus flavus or aflatoxin production. Two AFLP markers have been identified that are linked with resistance to seed invasion and one was converted into a SCAR marker for more efficient breeding application. Several new peanut cultivars with improved productivity and possessing resistance to aflatoxin contamination are extensively used in production. Integrated management approaches have been recommended to farmers based on agro-ecological characteristics in different regions. More recently, molecular techniques have been extensively used in genetic diversity assessment, investigation of genetic relationships among different germplasm groups, marker development, identification of interspecific genome introgression, gene cloning and function analysis, and genetic transformation of important traits concerning productivity, quality and food safety of peanut. Special emphasis has been placed on resistance to aflatoxin, bacterial wilt, foliar diseases and fatty acid desaturase. Perspectives of peanut genetic improvement and further research priorities are also discussed.

Use of Pyrosequencing to Quantify Incidence of a SpecificAspergillus flavusStrain Within Complex Fungal Communities Associated with Commercial Cotton Crops

Atoxigenic strains of Aspergillus flavus have been used as aflatoxin management tools on over 50,000 hectares of commercial crops since 2000. To assess treatment efficacy, atoxigenic strain incidence is routinely monitored by vegetative compatibility analyses (VCA) that require culturing, generation of auxotrophs, and complementation with tester mutants. Two pyrosequencing assays (PA) that require no culturing were developed for monitoring incidences of atoxigenic strains on ginned cottonseed. The assays, which quantify frequencies of characteristic single nucleotide polymorphisms (SNPs) in the aflR and pksA genes, were validated against standard VCA on cottonseed collected from commercial gins in South Texas, Arizona, and Southern California where the atoxigenic strain AF36 is used to manage aflatoxin contamination. Cottonseed washings were subjected to both VCA and PA. PA was performed directly on DNA isolated from particulates pelleted from the wash water by centrifugation. Addition of CaCl(2) and diatomaceous earth prior to pelleting increased the amount of DNA isolated. Accuracy and reproducibility of the PA were contrasted with those for the VCA that has been used for over a decade. Correlation coefficients between VCA and PA indicated good correspondence between the results from the two assays (r = 0.91 for aflR assay and r = 0.80 for pksA assay). PAs were highly variable for samples with low incidences of A. flavus due to variability in the initial polymerase chain reaction step. This held for both DNA isolated from cottonseed washes and for mixtures of purified DNA. For samples yielding low quantities of A. flavus DNA, averaging of results from 4 to 5 replicates was required to achieve acceptable correlations with VCA. Pyrosequencing has the potential to become a powerful tool for monitoring atoxigenic strains within complex A. flavus communities without limitations imposed by traditional culturing methods.

Reducing human exposure to aflatoxin through the use of clay: A review

Innovative sorption strategies for the detoxification of aflatoxins have been developed. NovaSil clay (NS) has been shown to prevent aflatoxicosis in a variety of animals when included in their diet. Results have shown that NS clay binds aflatoxins with high affinity and high capacity in the gastrointestinal tract, resulting in a notable reduction in the bioavailability of these toxins without interfering with the utilization of vitamins and other micronutrients. This strategy is being evaluated as a potential remedy for acute aflatoxicosis, and as a sustainable human intervention for aflatoxins via the diet. Phase I and II clinical trials confirmed the apparent safety of NS for further study in humans. A recent study in Ghanaians at high risk for aflatoxicosis has indicated that NS (at a dose level of 0.25%) is effective in decreasing biomarkers of aflatoxin exposure and does not interfere with the levels of serum vitamins A and E, and iron and zinc. In summary, enterosorption strategies/therapies based on NS clay are promising for the management of aflatoxins and as a sustainable public health intervention. The NS clay remedy is novel, inexpensive and easily disseminated. Based on the present research, aflatoxin sequestering clays should be rigorously evaluated in vitro and in vivo, and should meet the following criteria: (1) favourable thermodynamic characteristics of mycotoxin sorption, (2) tolerable levels of priority metals, dioxins/furans and other hazardous contaminants, (3) safety and efficacy in multiple animal species, (4) safety and efficacy in long-term studies, and (5) negligible interactions with vitamins, iron and zinc and other micronutrients.

Assessment of adoption gaps in the management of aflatoxin contamination of groundnut (Arachis hypogaea L.)

Groundnut (Arachis hypogaea L.) is an important oil seed crop of India. It has great potential for diversification to food uses due to its nutritive virtues. One of the major impediment for diversification is aflatoxin contamination. Aflatoxins are the toxic substances produced by strains of fungi belonging to Aspergillus flavus and A. parasiticus. The present study was undertaken during the 2005-06, rainy season in Junagadh, Gujarat, India to assess the adoption gaps in aflatoxin management practices of groundnut (AMPG) and the farmers characteristics influencing this gap. The district was selected because it was identified as one of the high risk area for aflatoxin contamination in rainy season. The results indicated that majority of the farmers were in high adoption gap category as most of the farmers had not adopted the harvest and post-harvest management practices. Farmer's characteristics knowledge, market orientation and innovativeness influenced the adoption gap significantly. Based on the results, it is suggested to formulate strategies to increase the knowledge of farmers through various extension approaches. The selection of innovative farmers for groundnut production and differentiating the contamined and afltoxin free groundnuts by the markets will help in reducing the adoption gap.

Farmers’ Perceptions of Quality of Groundnut: Vis-à-vis Farmers’ Characteristics

Groundnut is an important oil seed crop of India. In spite of its high nutritive value, 80% of the total production is utilized for oil extraction. It has great potential for diversification to food uses. Maintenance of quality is one of the major concerns for diversification. Apart from visual characters, such as pod shape, size, color, cleanliness, etc., aflatoxin contamination in kernels is considered as an important criterion for judging the quality of groundnut. Aflatoxins are the toxic substances produced by strains of fungi belonging to Aspergillus flavus and A. parasiticus. Aflatoxin contamination has led to human and cattle health concerns, significantly influencing groundnut trade worldwide. Aflatoxin contamination in groundnut pods has been reported to be more prevalent in Junagadh district compared to other groundnut growing districts of India. Hence, the study was undertaken to assess the perceptions of farmers on quality of groundnut in Junagadh district of Gujarat State, India. The results indicated that majority of farmers had low perception of quality and there were significant differences between the perceptions of big farmers and small farmers. The characteristics of farmers: knowledge of aflatoxin management practices, innovativeness, and market orientation significantly influenced the perceptions. Based on the results suggestions are made to formulate strategies to increase the knowledge level of farmers on aflatoxin management practices of groundnut through appropriate extension approaches. Mass awareness campaigns to educate farmers and consumers on the ill effects of consumption of aflatoxin contaminated produce, providing incentive price to farmers, building of consumer demands for aflatoxin free and good quality groundnuts are needed.

ASPERGILLUS FLAVUS INFECTION AND AFLATOXIN CONTAMINATION IN PEANUTS AT VARIOUS STAGES OF THE DELIVERY CHAINS IN WONOGIRI REGENCY, CENTRAL JAVA, INDONESIA

As a part of an Australian Centre for International Agricultural Research (ACIAR) project on management of aflatoxin in Indonesia and Australia (PHT 97/017), a survey on pre- and postharvest handling of peanuts at farmer, collector retailer levels, including Aspergillus flavus  infection and aflatoxin B1 contamination of peanuts collected in Wonogiri regency, Central Java, was conducted during the harvest period of the wet (February 2003) and dry (June 2003) seasons. Interviews using questionnaires, with farmers, collectors and retailers concerning pre- and post-harvest handling of peanuts were carried out. The moisture contents and physical quality of the peanut kernels were also determined. During the wet and dry seasons, fresh pod samples were collected from farmer fields (24 samples), dry raw pod samples from collector (24 samples) and raw kernel samples from retailer levels (54 samples). Thus, during each season 102 samples of various kinds of peanuts were collected for analysis. The A. flavus infection in kernel samples of peanuts collected from retailers were the highest, followed by samples collected from collectors and farmers. The A. flavus infection in kernel samples collected during the dry season was in general lower than in the wet season. It was alarming to note that all most all samples of raw kernel samples collected from retailers were infected by A. flavus during the wet and dry seasons. In general aflatoxin B1 levels in peanut samples collected in the wet season were higher than the dry season. During the wet and dry seasons, the aflatoxin B1 contents in retailer samples were the highest, followed by those collected from collectors and farmers. During the wet season, around 4, 17 and 33% of peanut samples collected from farmers, collectors and retailers, were respectively contaminated with more than 15 ppb of aflatoxin B1. During the dry season, around 42 and 74% of peanut samples collected from collectors and retailers, were respectively contaminated with more than 15 ppb of aflatoxin B1, while aflatoxin levels in wet raw pod samples collected from farmers were less than 15 ppb. In 2003 Codex Alimentarius Commission has determined a maximum level of total aflatoxins in peanuts intended for further processing at 15 ppb.

Ecology of aflatoxin producing fungi and biocontrol of aflatoxin contamination

Aflatoxins, highly toxic and carcinogenic compounds that frequently contaminate foods and feeds, are produced by several genera in the genusAspergillus. Aspergillus flavus, the most common species causing crop contamination, is a common inhabitant of the Sonoran desert of North America where it resides in complex communities composed of diverse individuals. This diversity reflects divergent adaptation to various ecological niches. SomeA. flavus isolates that are well adapted to plant associated niches do not produce aflatoxins yet have the capacity to competitively exclude aflatoxin producers. These atoxigenic strains can serve as biological control agents for management of aflatoxins in crops. Detailed knowledge of the ecology of aflatoxin-producing fungi may lead to novel practical methods for limiting contamination.

A rapid ELISA for screening aflatoxin B1 in animal feed and feed ingredients in Indonesia

To facilitate a sustainable aflatoxin management system in Indonesia, a simple, rapid and effective Enzyme Linked Immunosorbent Assay (ELISA) test for screening aflatoxin B1 (AFB1) in animal feed and feed ingredients was developed. Anti-AFB1 polyclonal antibodies were produced against AFB1-BSA and AFB1-KLH immunogens. Using AFB1 conjugated to horseradish peroxidase (HRP) as an enzyme marker in a direct competitive ELISA, an IC50 of 0.85±0.15 µg/kg and a detection limit (IC15) of 0.18±0.06 µg/kg of AFB1 were achieved. The assay was highly specific to AFB1 with very little cross reaction with other aflatoxin congeners (AFB2 0.9%, AFG1 3.1% and AFG2 1.2%) and metabolites. The ELISA was tolerant to methanol (up to 60%) and pH (pH 7.2–9.6) without significantly affecting the overall performance and was not affected by interferences from the animal feed and corn samples. Satisfactory recovery results were obtained from the spike and recovery study (77–97% recovery for 10–252 µg/kg). A pilot survey conducted on corn and animal feed samples collected from the local feed factories and poultry shops indicated that significant amounts of corn and animal feeds were contaminated by aflatoxin B1 greater than the MRL (50 µg/kg).