Challenges facing the biological control strategy for eliminating aflatoxin contamination

2015 ◽  
Vol 8 (2) ◽  
pp. 225-233 ◽  
Author(s):  
K.C. Ehrlich ◽  
G.G. Moore ◽  
J.E. Mellon ◽  
D. Bhatnagar
Keyword(s):  
Animal Health ◽  
Cost Benefit ◽  
Aflatoxin Production ◽  
Aflatoxin Contamination ◽  
Persistent Problem ◽  
Cost Benefit Ratio ◽  
Food And Feed ◽  
Potential Damage ◽  
The Stability ◽  
Biocontrol Strain

Competition with Aspergillus flavus isolates incapable of aflatoxin production is currently the most widely used biocontrol method for reducing aflatoxin contamination in maize and cottonseed where aflatoxin contamination is a persistent problem for human and animal health. The method involves spreading non-aflatoxigenic A. flavus spores onto the field prior to harvest. How competition works is not fully understood. Current theories suggest that atoxigenic A. flavus either simply displaces aflatoxin-producing isolates or that competition is an active inhibition process that occurs when the fungi occupy the same locus on the plant. In this paper we describe several challenges that the biocontrol strategy should address before this practice is introduced worldwide. These include the need to better understand the diversity of A. flavus populations in the agricultural soil, the effects of climate change on both this diversity and on plant susceptibility, the ability of the introduced biocontrol strain to outcross with existing aflatoxin-producing A. flavus, the adaptation of certain A. flavus isolates for predominant growth on the plant rather than in the soil, the difficulty in timing the application or controlling the stability of the inoculum, the effect of the introduction of the biocontrol strain on the soil microenvironment, the potential damage to the plant from the introduced strain, and the overall need to better understand the entire A. flavus toxin burden, beyond that of aflatoxin, that may result from A. flavus contamination. In addition, the cost/benefit ratio for the biocontrol method should be considered in comparing this method to other methods for reducing food and feed contamination with aflatoxins.

scholarly journals Temperature Influences on Interactions Among Aflatoxigenic Species of Aspergillus Section Flavi During Maize Colonization

2021 ◽  
Vol 2 ◽  
Author(s):  
Connel Ching'anda ◽  
Joseph Atehnkeng ◽  
Ranajit Bandyopadhyay ◽  
Kenneth A. Callicott ◽  
Marc J. Orbach ◽  
...  
Keyword(s):  
Species Interactions ◽  
Type Species ◽  
Animal Health ◽  
Aflatoxin Production ◽  
Fungal Species ◽  
Aflatoxin Contamination ◽  
Fungal Metabolites ◽  
Food And Feed ◽  
Temporal And Spatial ◽  
Maize Kernels

Fungal species within Aspergillus section Flavi contaminate food and feed with aflatoxins. These toxic fungal metabolites compromise human and animal health and disrupt trade. Genotypically and phenotypically diverse species co-infect crops, but temporal and spatial variation in frequencies of different lineages suggests that environmental factors such as temperature may influence structure of aflatoxin-producing fungal communities. Furthermore, though most species within Aspergillus section Flavi produce sclerotia, divergent sclerotial morphologies (small or S-type sclerotia vs. large or L-type sclerotia) and differences in types and quantities of aflatoxins produced suggest lineages are adapted to different life strategies. Temperature is a key parameter influencing pre- and post-harvest aflatoxin contamination of crops. We tested the hypothesis that species of aflatoxin-producing fungi that differ in sclerotial morphology will vary in competitive ability and that outcomes of competition and aflatoxin production will be modulated by temperature. Paired competition experiments between highly aflatoxigenic S-type species (A. aflatoxiformans and Lethal Aflatoxicosis Fungus) and L-type species (A. flavus L morphotype and A. parasiticus) were conducted on maize kernels at 25 and 30°C. Proportions of each isolate growing within and sporulating on kernels were measured using quantitative pyrosequencing. At 30°C, S-type fungi were more effective at host colonization compared to L-type isolates. Total aflatoxins and the proportion of B vs. G aflatoxins were greater at 30°C compared to 25°C. Sporulation by L-type isolates was reduced during competition with S-type fungi at 30°C, while relative quantities of conidia produced by S-type species either increased or did not change during competition. Results indicate that both species interactions and temperature can shape population structure of Aspergillus section Flavi, with warmer temperatures favoring growth and dispersal of highly toxigenic species with S-type sclerotia.

scholarly journals Aflatoxin contamination in Tanzania: quantifying the problem in maize and groundnuts from rural households

2021 ◽  
pp. 1-12
Author(s):  
S.B. Boni ◽  
F. Beed ◽  
M.E. Kimanya ◽  
E. Koyano ◽  
O. Mponda ◽  
...  
Keyword(s):  
Body Weight ◽  
High Performance ◽  
Animal Health ◽  
Daily Intake ◽  
Aflatoxin Contamination ◽  
Aflatoxin Level ◽  
Awareness Campaigns ◽  
Food And Feed ◽  
The Mean ◽  
Aflatoxin B

Aflatoxins are toxic and carcinogenic secondary metabolites, produced by Aspergillus flavus and Aspergillus parasiticus, which contaminate food and feed and threaten human and animal health. To assess the prevalence of aflatoxins in Tanzania, 180 groundnut and 200 maize samples were collected from 9 and 10 districts, respectively. Aflatoxin contamination was quantified using high performance liquid chromatography. Aflatoxins were detected in samples collected from all districts and prevalence ranged from 92 to 100% for groundnuts and 10 to 80% for maize. The mean aflatoxin level for groundnuts was 6.37 μg/kg and the highly contaminated sample had 40.31 μg/kg. For maize, the mean aflatoxin level was 12.47 μg/kg and the highly contaminated sample had 162.40 μg/kg. The estimated average probable daily intake (APDI) of aflatoxin B1 (AFB1) from groundnuts consumption was 1.88 ng/kg body weight/day, while for maize, it ranged between 151.98-272.89 ng/kg body weight/day. The APDI for both groundnut and maize exceeded the provisional maximum tolerable daily intake (PMTDI) of AFB1 for adults (1 ng/kg body weight/day), bringing about health concerns for populations in Tanzania. Another alarming finding was that 75% of the farmers who provided samples for analysis were not aware of aflatoxins or the negative health impacts from consuming contaminated products. Results reported in this paper show that aflatoxin contaminated staple crops are widely distributed in Tanzania and that the risk of human exposure is high due to diet preferences. Awareness campaigns are required to inform and protect farmers and consumers.

scholarly journals Aflatoxin Contamination in Agricultural Commodities

2013 ◽  
Vol 1 (04) ◽  
pp. 148-151 ◽  
Author(s):  
P. N. Rajarajan ◽  
K. M. Rajasekaran ◽  
N. K. Asha Devi
Keyword(s):  
Aspergillus Flavus ◽  
Aflatoxin B1 ◽  
Animal Health ◽  
Aflatoxin Contamination ◽  
Aflatoxin M1 ◽  
Organic Substrates ◽  
Naturally Occurring ◽  
Food And Feed ◽  
Hydroxylated Metabolite ◽  
Carcinogenic Compound

Aflatoxin is a naturally occurring Mycotoxin produced by Aspergillus flavus and Aspergillus parasiticus. Aspergillus flavus is common and widespread in nature and is most often found when certain grains are grown under stressful conditions such as draught. The mold occurs in soil, decaying vegetation, hay and grains undergoing microbiological deterioration and invades all types of organic substrates whenever and wherever the conditions are favourable for its growth. Favourable conditions include high moisture content and high temperature.The aflatoxin group is comprised of aflatoxin B1,B2,G1 and G2. In addition , aflatoxin M1 (AFM1), a hydroxylated metabolite of AFB1, is excreted in the milk of dairy cows consuming an AFB1-contaminated ration. Aflatoxin B1 a prototype of the aflatoxins, is widely recognized as the most potent hepato carcinogenic compound and along with other certain members of the group, possess additional toxic properties including mutagenicity, tetrogenicity, acute cellular toxicity and it suppresses the immune system. Aflatoxin contamination of food and feed has gained global significance as a result of its deleterious effects on human as well as animal health. The marketability of food products is adversely affected by aflatoxin contamination.

scholarly journals Mycotoxins: Risks, regulations and European co-operation

2013 ◽  
pp. 7-20 ◽  
Author(s):  
Egmond Van
Keyword(s):  
Animal Feed ◽  
Animal Health ◽  
Cost Benefit ◽  
Negative Influence ◽  
Adequate Sampling ◽  
Food And Feed ◽  
To Come ◽  
Scientific Attention ◽  
The Eu ◽  
Socio Economic Factors

Mycotoxins and mycotoxicises have been problems of the past and the present, but scientific attention for mycotoxins did not start until the early 1960?s. Nowa?days, many mycotoxins are known, and their occurrence in food and animal feed may cause various adverse effects on human and animal health, including carcinogenic, hepatotoxic, immunotoxic, nephrotoxic, neurotoxic, oestrogenic and teratogenic effects. Some important mycotoxins include the aflatoxins, ochratoxin A, the fumonisins and the trichothecenes, and their significance is briefly described. To protect human and animal health, many countries have enacted specific regulations for mycotoxins in food and animal feed. Risk assessment is a major factor for scientific underpinning of regulations, but other factors such as availability of adequate sampling and analysis procedures also play an important a role in the establishment of mycotoxin regulations. In addition, socio-economic factors such as cost-benefit considerations, trade issues and sufficiency of food supply are equally important in the decision-taking process to come to meaningful regulations. Nowadays, more than 100 countries have formal mycotoxin regulations for food and feed. The mycotoxin regulations are the most stringent in the EU, where various organizations and pan-European networks contribute to combat the mycotoxin problem. It is to be expected that mycotoxins will stay with us in the future and climate change might have a negative influence in this respect. Several possibilities exist to mitigate the problems caused by mycotoxins. In particular prevention of mould growth and mycotoxin formation is key to the control of mycotoxins.

scholarly journals The Development of a qPCR Assay to Measure Aspergillus flavus Biomass in Maize and the Use of a Biocontrol Strategy to Limit Aflatoxin Production

Toxins ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 179 ◽  
Author(s):  
Alfred Mitema ◽  
Sheila Okoth ◽  
Suhail Rafudeen
Keyword(s):  
Aspergillus Flavus ◽  
Significant Variation ◽  
Animal Health ◽  
Aflatoxin Production ◽  
Health Screening ◽  
Aflatoxin Contamination ◽  
Qpcr Assay ◽  
First Report ◽  
Bioanalytical Techniques

Aspergillus flavus colonisation of maize can produce mycotoxins that are detrimental to both human and animal health. Screening of maize lines, resistant to A. flavus infection, together with a biocontrol strategy, could help minimize subsequent aflatoxin contamination. We developed a qPCR assay to measure A. flavus biomass and showed that two African maize lines, GAF4 and KDV1, had different fungal loads for the aflatoxigenic isolate (KSM014), fourteen days after infection. The qPCR assay revealed no significant variation in A. flavus biomass between diseased and non-diseased maize tissues for GAF4, while KDV1 had a significantly higher A. flavus biomass (p < 0.05) in infected shoots and roots compared to the control. The biocontrol strategy using an atoxigenic isolate (KSM012) against the toxigenic isolate (KSM014), showed aflatoxin production inhibition at the co-infection ratio, 50:50 for both maize lines (KDV1 > 99.7% and GAF ≥ 69.4%), as confirmed by bioanalytical techniques. As far as we are aware, this is the first report in Kenya where the biomass of A. flavus from maize tissue was detected and quantified using a qPCR assay. Our results suggest that maize lines, which have adequate resistance to A. flavus, together with the appropriate biocontrol strategy, could limit outbreaks of aflatoxicoses.

scholarly journals Determination of Aflatoxin Concentrations in Cereals and Legumes Marketed in Zaria Metropolis, Kaduna State, Nigeria

2021 ◽  
Vol 6 (1) ◽  
pp. 208-218
Author(s):  
S. Shitu ◽  
◽  
M. Attahiru ◽  
H. Umar
Keyword(s):  
Immunosorbent Assay ◽  
Uv Light ◽  
Aflatoxin Production ◽  
Neutral Red ◽  
Proximate Analysis ◽  
Aflatoxin Contamination ◽  
Enzyme Linked Immunosorbent Assay ◽  
High Concentration ◽  
Crude Lipid ◽  
Food And Feed

Aflatoxins are group of secondary fungal metabolites produced by Aspergillus species, such as Aspergillus flavus and Aspergillus parasiticus. The aflatoxin producing moulds can grow on cereals and legumes in the field, poorly dried harvested crops in storage, processed food, and feed products. The study was carried out with the aim to determine the level of aflatoxin contamination of cereals grain and legumes in Zaria metropolis, Kaduna State, Nigeria. Ninety (90) samples were collected, which comprises of 18 samples each of millet, sorghum, maize, beans, and groundnuts respectively. The samples were subjected to proximate analysis. The grains were further subjected to cultural isolation and microscopic identification. The isolates were then screened for aflatoxin production ability with neutral red desiccated coconut agar and viewed under UV light (365nm). The remaining portions of the samples was grounded and extracted with 80% (v/v) methanol. The enzyme-linked Immunosorbent Assay (ELISA) technique was used in quantifying the total aflatoxin content of the samples. The results revealed that all the cereals and legumes analysed contain organic and inorganic nutrients that can support the growth of aflatoxigenic moulds and production of aflatoxins. Some major parameters such as carbohydrate content, crude protein, crude lipid, and ash contents were statistically significant (p < 0.05). Thirty-one (31) isolates from the 90 samples were confirmed to be A. flavus and seventeen (17) were A. Parasiticus, with percentage occurrence of 34.4% and 18.9% respectively. All the isolates were screened and demonstrated ability for aflatoxin production under UltraViolent light (390nm). The results also revealed a high concentration of aflatoxin (11.04 µg/kg) in millet and a low concentration in sorghum (1.07 µg/kg). The contamination levels within the grains were found to be statistically significant (p < 0.05). Aflatoxin contaminations also occurred in 48 samples out of the 90 samples analysed. The grains samples analysed were found to be contaminated with varying amounts of aflatoxins, which is harmful to humans and animals. Therefore, steps should be taken to ensure that grains are properly dried prior to storage. Keywords: aflatoxin, A. flavus, A. parasiticus, cereals, Enzyme-linked Immunosorbent Assay, legumes

scholarly journals Implication of aflatoxins as potent carcinogens

2020 ◽  
Vol 12 (1) ◽  
pp. 39-45
Author(s):  
Fatima Mukhtar
Keyword(s):  
Animal Health ◽  
Food Products ◽  
Aflatoxin Contamination ◽  
International Agency ◽  
Attractive Alternative ◽  
Statistical Tool ◽  
Post Harvest ◽  
Global Challenge ◽  
Mycotoxigenic Fungi ◽  
Food And Feed

Aspergillus species influence human and animal health directly and indirectly with a significant economic impact on the society. A. flavus and A. parasiticus are the two major species that produce aflatoxins. Several mycotoxins are reported from several other mycotoxigenic fungi of which the aflatoxins are the most toxic and damaging polyketides. Economically important crops such as maize, rice, cotton seed, peanuts, and spices are all susceptible to contamination of aflatoxin. The aim of this review is to make an extensive review and come up with ways to curtail this global challenge on how to manage aflatoxin contamination in crops and other food products since the toxins have been classified as potent carcinogens and about 25% of food is being lost due to aflatoxin contamination annually. The International Agency for Research on Cancer (IARC) conducted evaluation of several chemicals of their carcinogenic potential and classified aflatoxins as most potent natural, known human carcinogens. The methodology was by selecting the most recent researches conducted on new techniques to be employed in overcoming the issue of aflatoxin contamination both during the pre and post-harvest strategies. The Data gathered was subjected to appropriate statistical tool so as to come up with more improved techniques. It was found that both chemical and physical methods have certain drawbacks which may lead to drop in human and animal health, cause a significant decline in the quality of food products, losses of nutritional value, high cost and cause undesirable health effects, but biological methods using microorganisms seems more promising, they provide an attractive alternative tool for removing toxins and safeguarding the value of food and feed in an eco-friendly way. Key words: Aflatoxin, Contamination, Crops, Pre and Post-harvest.

scholarly journals Review of Immunological Methods for the Quantification of Aflatoxins in Peanut and Other Foods

2009 ◽  
Vol 36 (1) ◽  
pp. 54-59 ◽  
Author(s):  
Farid Waliyar ◽  
S. V. Reddy ◽  
P. Lava-Kumar
Keyword(s):  
State Of The Art ◽  
Quantitative Estimation ◽  
Animal Health ◽  
Field Studies ◽  
Developed Countries ◽  
Aflatoxin Contamination ◽  
Immunological Methods ◽  
Food And Feed ◽  
High Risk Populations ◽  
Resistant Genotypes

Abstract Aflatoxin contamination is widespread in staple crops like peanut, maize, sorghum, pearl millet, chillies, pistachio, cassava etc., and compromises the safety of food and feed supplies. It is important to be able to detect and quantify aflatoxins in commodities to protect human and animal health. Many different methods, including antibody-based ones, are available for quantitative estimation of aflatoxins. However, most of these methods such as HPLC, HPTLC, and TLC are expensive and/or difficult to use in developed countries. Using the state-of-the-art facilities at ICRISAT, we developed polyclonal and monoclonal antibodies for the detection of total aflatoxins, aflatoxin B1 and M1 (secreted in milk). These were used to develop a simple and inexpensive competitive enzyme-linked immunosorbent assays (cELISA) that has lower detection limits (1.0 µg/kg) and cost (about $1 per sample) less than other available methods. More than 100 samples can be analyzed in a day. These tests have provided a unique opportunity for ICRISAT and its partners to conduct field studies to select resistant genotypes, identify high risk populations and determine the dietary sources to stimulate appropriate interventions to enhance the food and human health safety, trade and thereby farmers' income.

Tissue- and development-specific induction and turnover of hsp70 transcripts from loci 87A and 87C after heat shock and during recovery inDrosophila melanogaster

2002 ◽  
Vol 205 (3) ◽  
pp. 345-358 ◽  
Author(s):  
S. C. Lakhotia ◽  
K. V. Prasanth
Keyword(s):  
Heat Shock ◽  
Cost Benefit ◽  
Cell Types ◽  
Specific Induction ◽  
Cost Benefit Ratio ◽  
Multiple Copies ◽  
The Stability ◽  
The Cost ◽  
Different Cell Types

SUMMARYThe haploid genome of Drosophila melanogaster normally carries at least five nearly identical copies of heat-shock-inducible hsp70 genes, two copies at the 87A7 and three copies at the 87C1 chromosome sites. We used in situ hybridization of the cDNA, which hybridizes with transcripts of all five hsp70 genes, and of two 3′ untranslated region (3′UTR; specific for the 87A7- and 87C1-type hsp70 transcripts) riboprobes to cellular RNA to examine whether all these copies were similarly induced by heat shock in different cell types of D. melanogaster. Our results revealed remarkable differences not only in the heat-shock-inducibility of the hsp70 genes at the 87A7 and 87C1 loci, but also in their post-transcriptional metabolism, such as the stability of the transcripts and of their 3′UTRs in different cell types in developing embryos and in larval and adult tissues. Our results also revealed the constitutive presence of the heat-shock-inducible form of Hsp70 in a subset of late spermatogonial cells from the second-instar larval stage onwards. We suggest that the multiple copies of the stress-inducible hsp70 genes do not exist in the genome of D. melanogaster only to produce large amounts of the Hsp70 rapidly and at short notice, but that they are specifically regulated in a developmental-stage-specific manner. It is likely that the cost/benefit ratio of not producing or of producing a defined amount of Hsp70 under stress conditions varies for different cell types and under different physiological conditions and, accordingly, specific regulatory mechanisms operating at the transcriptional and post-transcriptional levels have evolved.

scholarly journals Control of Aflatoxigenic Molds by Antagonistic Microorganisms: Inhibitory Behaviors, Bioactive Compounds, Related Mechanisms, and Influencing Factors

Toxins ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 24 ◽  
Author(s):  
Xianfeng Ren ◽  
Qi Zhang ◽  
Wen Zhang ◽  
Jin Mao ◽  
Peiwu Li
Keyword(s):  
Bioactive Compounds ◽  
Crop Production ◽  
Aflatoxin Production ◽  
Aflatoxin Contamination ◽  
Key Factors ◽  
Toxicological Effects ◽  
Factors Influencing ◽  
Antagonistic Microorganisms ◽  
Aflatoxigenic Fungi ◽  
Food And Feed

Aflatoxin contamination has been causing great concern worldwide due to the major economic impact on crop production and their toxicological effects to human and animals. Contamination can occur in the field, during transportation, and also in storage. Post-harvest contamination usually derives from the pre-harvest infection of aflatoxigenic molds, especially aflatoxin-producing Aspergilli such as Aspergillus flavus and A. parasiticus. Many strategies preventing aflatoxigenic molds from entering food and feed chains have been reported, among which biological control is becoming one of the most praised strategies. The objective of this article is to review the biocontrol strategy for inhibiting the growth of and aflatoxin production by aflatoxigenic fungi. This review focuses on comparing inhibitory behaviors of different antagonistic microorganisms including various bacteria, fungi and yeasts. We also reviewed the bioactive compounds produced by microorganisms and the mechanisms leading to inhibition. The key factors influencing antifungal activities of antagonists are also discussed in this review.

Sign in / Sign up

Export Citation Format

Share Document