Aflatoxin Contamination In Groundnut Research Articles

Prevalence and potential for aflatoxin contamination in groundnuts and peanut butter from farmers and traders in Nairobi and Nyanza provinces of Kenya

Objective: Most of the peanut butter marketed in Nairobi is processed in cottage industry and its aflatoxin contamination status has not been documented. This study was therefore conducted to determine the status of aflatoxin contamination in groundnuts and peanut butter in Nairobi and Nyanza. Methodology and results: Eighty two fresh samples comprising raw and roasted groundnuts and peanut butter were obtained from market outlets and cottage processors in Nairobi and Nyanza regions. The marketers and processors were asked for information on the source of groundnuts. The incidence of Aspergillus section Flavi was determined using standard laboratory methods. Defective nuts in raw groundnuts were determined by manual sorting. Aflatoxin analysis was done using competitive ELISA technique. Groundnuts in Nairobi were imported from Malawi while those Nyanza were grown in the region. The fungal species isolated from the samples were: Aspergillus flavus (L and S strains), A. parasiticus, A. niger, A. tamari, A. alliaceus , A. caeletus and Penicillium spp . The percentage of defective nuts among all unsorted groundnuts ranged from 0.0% to 26.3%. The mean percent defective nuts was higher for Nairobi samples than Nyanza. Aflatoxin levels in all samples ranged from 0 to 2377.1 µg/kg. The mean aflatoxin level was higher for raw samples from Nairobi than Nyanza. The source of groundnuts and defective nuts were positively associated with aflatoxin levels. Conclusions and application of findings: The source of groundnuts and presence of defective nuts were identified as the main factors influencing increased aflatoxin contamination in the cottage industry. Mechanisms for inspection and certification of imported groundnuts should be put in place accompanied by effective monitoring for compliance to set aflatoxins standards. All the market players should sort their groundnuts before selling or processing in order to reduce aflatoxin contamination of peanut butter.

Occurrence and distribution of aflatoxin contamination in groundnuts (Arachis hypogaea L) and population density of Aflatoxigenic Aspergilli in Malawi

Groundnut (Arachis hypogaea L.) is susceptible to pre- and post-harvest infections by Aspergillus spp. Aflatoxin B1 (AFB1), is the contaminant produced by the fungus in infected grains posing a threat to human and animal health. This paper reports of a study undertaken in Malawi to determine the occurrence and distribution of Aflatoxigenic Aspergilli in the soil and AFB1 contamination in groundnuts. A total of 1397 groundnut samples collected from farm homesteads, local markets, warehouses and shops in 2008 and 2009 were analyzed for AFB1 contamination using the enzyme linked immunosorbent assay (ELISA), and A. Aspergilli population densities in 1053 soil samples collected from the same sites were estimated using serial dilutions plated on A. Aspergilli medium. Farmer socio-economic profile information was also collected to determine relationships to AFB1 contamination. The results revealed 46% and 23% of the total samples, from 2008 to 2009, respectively, had AFB1 contamination levels greater than 4 ppb, and those above 20 ppb were 21% for 2008 and 8% for 2009, respectively. Fitted smooth curve relationships show that there is a clear increase in the chance of groundnut contamination when the population density of A. Aspergilli in the soil increased beyond 3000 (log (cfu) > 8). The measured level of A. Aspergilli in soil varied by location, as well as ecologies within location. Low-altitude ecologies, which were warmer and experienced low precipitation levels, had the highest densities of A. Aspergilli, whereas cooler high-altitude ecologies had the lowest density of these fungi. Similarly high AFB1 contamination, was recorded across the country with 11–28% of all samples collected from the warm low to mid-altitude ecologies recording contamination ≥20 ppb and low contamination (2–10% of samples) in the mid to high altitude cool ecologies. From a crop management perspective, this study also suggests that both less experienced and older farmers were more likely to produce groundnuts contaminated with aflatoxin. These findings have implications in the design of intervention strategies to avoid short- and long-term human health effects from aflatoxin exposure.

Knowledge of aflatoxin contamination in groundnut and the risk of its ingestion among health workers in Ibadan, Nigeria

Objective To assess the awareness and knowledge of aflatoxin contamination in groundnut and the risk of its ingestion among health workers in Ibadan. Methods The study was a descriptive cross-sectional study. Study instrument was a semi-structured self administered questionnaire. The respondents were health workers from a public health facility. Results A total of 417 health workers participated out of which males were 60.2%. The mean age of respondents was (28.0+4.9)years old. Doctors made up 83.0% while others were nurses. 95% of the respondents had previous awareness of aflatoxin and class room lectures was the most common source of information (56%). Occupation and religion both showed a significant association with previous awareness of aflatoxin ( P < 0.05). Knowledge regarding aflatoxin contamination in groundnut and the risk of its ingestion was obtained showing knowledge score range of 0 to 14. In all, 80.6% had good scores of 11 to 14. None of the respondents had ever told their patients about the risk of aflatoxin ingestion. Conclusions There is a need to explore the possibility of incorporating aflatoxin awareness into routine health talk to increase the level of awareness of patients and their relatives.

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.

Isolation and screening of biocontrol bacterial strains against Aspergillus parasiticus from groundnut geocarposphere

INTRODUCTION Aspergillus parasiticus Speare and A. flavus Link are two major fungi species that produce aflatoxins in agricultural commodities, such as groundnut, corn and cottonseeds. Because of the potency of aflatoxins as carcinogens and the associated food and feed safety hazards, worldwide regulatory limits have been established for aflatoxins in food and animal feeds (van Egmond, 1995). Groundnut (Arachis hypogaea L.) is a major oilseed crop widely grown in tropical and subtropical regions of the world. Aflatoxin contamination of groundnut by A. flavus and A. parasiticus is a serious problem and has a tremendous impact on the global groundnut industry as well as posing public health risks (Anjaiah et al., 2006). Therefore, control of aflatoxin contamination is very crucial for food and feed safety. Bacteria have been investigated for antifungal and aflatoxin-inhibiting activity against A. flavus and

Integrated management of aflatoxin B1 contamination of groundnut (Arachis hypogaea L.) with Burkholderia sp. and zimmu (Allium sativum L.×Allium cepa L.) intercropping

The efficacy of intercropping of the medicinal plant zimmu (Allium sativum L.×Allium cepa L.) and an antagonistic bacterium Burkholderia sp. strain TNAU-1 was evaluated separately and in combination for control of Aspergillus flavus infection and aflatoxin B1 contamination in groundnut (Arachis hypogaea L.) under field conditions. The Burkholderia sp. strain TNAU-1 inhibited the growth of all the toxigenic and non-toxigenic isolates of A. flavus in vitro and the inhibition zone ranged from 3.1–11.3 mm. A talc-based powder formulation of the Burkholderia sp was developed for field application. When groundnut seeds were treated with the formulation of Burkholderia sp., significant increases in root length, shoot length and seedling vigor were observed. Zimmu intercropping (once in every three rows of groundnut) alone significantly reduced the A. flavus infection and aflatoxin contamination in groundnut. Seed treatment at 10 g/kg or soil application at 2.5 kg/ha on 30, 45, 60 days after sowing with the formulation of Burkholderia sp. also resulted in significant reduction in the infection by A. flavus and aflatoxin B1 contamination in kernels. The maximum percentage reduction in aflatoxin B1 content was achieved by the combination of zimmu intercropping, seed treatment and soil application of Burkholderia sp. Seed treatment followed by soil application with the formulation of Burkholderia sp. recorded the highest pod yield in both the field trials. Zimmu intercropping or seed treatment or soil application with formulation of Burkholderia sp. significantly reduced the population of A. flavus in the soil. Application of Burkholderia sp. through seed or soil resulted in high colonization of Burkholderia sp. in rhizosphere soil, and the rhizosphere population increased with increase in the age of the crop. A colony PCR assay was developed using primers made to Burkholderia sp. specific sequence of the ribosomal DNA for accurate detection and confirmation of Burkholderia sp.

AFLP Analysis of Trichoderma spp. from India Compared with Sequence and Morphological‐based Diagnostics

Abstract Trichoderma species offer considerable potential for controlling aflatoxin contamination in groundnut and other crops. Initial classification of 48 Trichoderma isolates, derived from four different groundnut cultivation sites in India was based on alignment of 28S rDNA sequences to GenBank sequences of ex‐type strains. This was found to be substantially more reliable than our routine morphological characterization, but did not provide a comprehensive diagnostic solution, as unique single nucleotide polymorphism (SNP) haplotypes could not be identified for all species. However, all the Trichoderma isolates could be readily distinguished by amplified fragment length polymorphism (AFLP) analysis, based on six primer pair combinations, which generated 234 polymorphic bands. In addition, individual AFLP bands were identified which differentiate closely related species. Similarly, AFLP bands were identified that correlated with different types of antagonism to Aspergillus flavus. The implications of these results for the development of simple polymerase chain reaction (PCR)‐based diagnostic assays for antagonistic isolates of Trichoderma is discussed.

Preharvest seed infection byAspergillus flavus group fungi and subsequent aflatoxin contamination in groundnuts in relation to soil types

Preharvest seed infection byAspergillus flavus and aflatoxin contamination in selected groundnut genotypes (fourA. flavus-resistant and fourA. flavus-susceptible) were examined in different soil types at several locations in India in 1985–1990. Undamaged mature pods were sampled at harvest and seed examined forA. flavus infection and aflatoxin content in two or more trials at ICRISAT Center on light sandy soils and red sandy loam soils (Alfisols), and on Vertisols, at Anantapur on light sandy soils, and at Dharwad and Parbhani on Vertisols. Rainy season trials (1985–1989) were all rainfed. Post-rainy season trials were irrigated; late-season drought stress (90 days after sowing (DAS) until harvest at 125 DAS) was imposed in the 1987/88 and 1989/90 seasons.A. flavus infection and aflatoxin contamination levels were much lower in seed of all genotypes from Vertisols than in seed from Alfisols across locations and seasons. Vertisols also had significantly lower populations ofA. flavus than Alfisols. There were no marked differences between light sandy soils and red sandy loam soils (Alfisols) in respect of seed infection byA. flavus and aflatoxin contamination. Significant interactions between genotypes and soil types were evident, especially in theA. flavus-susceptible genotypes. Irrespective of soil types,A. flavus-resistant genotypes showed lower levels of seed infection byA. flavus and other fungi than didA. flavus-susceptible genotypes. The significance of the low preharvest aflatoxin risk in groundnuts grown on Vertisols is highlighted.

Aflatoxin contamination of groundnuts in Sudan.

Groundnut samples, collected soon after harvest, from different districts in the irrigated region (Central Sudan) were free from aflatoxins with the method used. Samples collected from the rainfed region (Western Sudan) showed variable levels of aflatoxin ranging from 100% sample contamination in El Hamdi to only 10% in Casgeal. Damaged pods were highly contaminated with A. flavus and accumulated large amounts of aflatoxins. However, sound intact pods, recorded lower fungal contamination and were almost free of aflatoxins. Groundnut products collected from Khartoum North (Bahri) have higher levels of aflatoxins than those collected from Khartoum and Umdorman. Gray and red roasted pods showed higher amounts of aflatoxins, while the groundnut past was the least contaminated. None of the three varieties of groundnuts tested in this work was completely resistant to aflatoxin production. A temperature of 30 degrees C and 86.3% relative humidy (RH) are the optimum conditions for both A. flavus growth and aflatoxin production in groundnuts.

Epidemiology of Aflatoxin Formation by Aspergillus Flavus*

The epidemiology of aflatoxin contamination in groundnuts, maize and cottonseed, the life cycle of the fungus from sources of primary and secondary inoculum, the mode of entry of A. flavus into the plant, seed infection and, finally, aflatoxin formation in the seed is reviewed.

Research on the aflatoxin problem in groundnut at ICRISAT

Aflatoxin contamination of groundnut is a serious problem in most groundnut producing countries and as such is given high research priority by the Groundnut Improvement Program of ICRISAT. Since 1979 we have concentrated on selecting cultivars resistant to seed invasion and colonization by toxigenicAspergillus flavus, and/or to aflatoxin production following invasion by the fungus. Resistance to invasion and colonization byA. flavus of rehydrated, mature seed has been found, and confirmed, in some cultivars. We have also screened several groundnut cultivars for seed resistance in the field, both under natural conditions and with the inoculum of the fungus added to the soil in the pod zone. Some cultivars with resistance to seed colonization also showed resistance to seed invasion byA. flavus. None of the cultivars tested has shown complete resistance to aflatoxin production but significant cultivar differences occurred in the amounts of aflatoxin produced in seeds inoculated with a toxigenic strain ofA. flavus.

The Aflatoxin Problem: Industry-FDA-USDA Cooperation

The role groundnut growers, shellers and manufacturers of consumer groundnut products, together with USDA and FDA, played in forming a joint task force to develop a programme of research into incidence, causes and control of aflatoxin contamination of groundnuts and groundnut products is recounted