Low Levels Of Aflatoxin Research Articles

Changes in cottonseed meal quality during post-harvest processing of cottonseed

This study investigates aflatoxin contamination levels during the post-harvest processing of whole cottonseed into defatted cottonseed meal, a critical feed component in the dairy industry. Whole fuzzy cottonseed, a byproduct of cotton gins, undergoes various processes to extract oil and produce meal and hulls. These are either used as animal feed or soil amendments. However, aflatoxin contamination poses significant challenges due to strict FDA action levels for dairy and beef cattle feed. This contamination occurs when Aspergillus flavus infects crops under specific environmental conditions or through improper handling during post-harvest processes. Our research aims to document aflatoxin levels during each stage of post-harvest processing, from cleaning to meal formation. Preliminary findings suggest that certain stages may concentrate aflatoxins akin to other agricultural products like dried distillers’ grains and solubles (DDGS). The implications of these findings could be profound for the dairy industry, where low allowable aflatoxin levels impact both economic and animal health outcomes. The cottonseed post-harvest process consists of cleaning, delinting, hull removal, kernel flaking, oil extraction, and meal formation. Understanding how aflatoxin levels change during these steps is crucial for ensuring safe and high-quality defatted cottonseed meal for livestock consumption. Microbial levels increased by 4 orders of magnitude during the acid delinting process, from 7.0× 105 to 5.2 × 109 CFU/g, and 5 orders of magnitude during the mechanical delinting process, from 7.3× 105 to 1.5 × 1010 CFU/g for the inoculated cottonseed samples. Higher microbial load was associated with lower protein levels and lower fat acidity levels. Further research will shed light on the effects of aflatoxin concentration on the nutritional value of the final product.

Exploring mitigating factors for aflatoxin awareness and incidence among smallholder groundnut farmers in Sub-Saharan Africa

Abstract This study considers the association between agricultural extension, aflatoxin, and good management practices among smallholder groundnut farmers in sub-Saharan Africa. The first part examines extension and self-reported knowledge and perceptions of aflatoxin for three countries. This is done using pooled survey data (n = 1388) collected from 2014 to 2016, beginning with Uganda (n = 480) in 2014, Ghana (n = 537) in 2015, and Mozambique (n = 335) in 2016. Results from probit regressions suggest that aflatoxin knowledge and perceptions are related to village extension services, household head education, farm size, groundnut production area, and experience with aflatoxins. To build upon these findings, additional information on aflatoxin levels and good management practices for a sub-sample of the 2015 Ghana survey (n = 134) is analysed. Negative binomial regression estimates indicate significantly lower aflatoxin levels for households that (1) follow good management practices and (2) are in receipt of village extension services, with the lowest average aflatoxin level from the combination of (1) and (2). These findings underscore the role of extension in combating the incidence of aflatoxin in groundnut value chains. In this way, extension is associated with greater knowledge and perceptions, as well as lower levels of aflatoxin, that can be further reduced with good management practices.

Aflatoxin contamination of maize and groundnut in Burundi: Distribution of contamination, identification of causal agents and potential biocontrol genotypes of Aspergillus flavus.

Aflatoxin contamination of the staples maize and groundnut is a concern for health and economic impacts across sub-Saharan Africa. The current study (i) determined aflatoxin levels in maize and groundnut collected at harvest in Burundi, (ii) characterized populations of Aspergillus section Flavi associated with the two crops, and (iii) assessed aflatoxin-producing potentials among the recovered fungi. A total of 120 groundnut and 380 maize samples were collected at harvest from eight and 16 provinces, respectively. Most of the groundnut (93%) and maize (87%) contained aflatoxin below the European Union threshold, 4 μg/kg. Morphological characterization of the recovered Aspergillus section Flavi fungi revealed that the L-morphotype of A. flavus was the predominant species. Aflatoxin production potentials of the L-morphotype isolates were evaluated in maize fermentations. Some isolates produced over 137,000 μg/kg aflatoxin B1. Thus, despite the relatively low aflatoxin levels at harvest, the association of both crops with highly toxigenic fungi poses significant risk of post-harvest aflatoxin contamination and suggests measures to mitigate aflatoxin contamination in Burundi should be developed. Over 55% of the L-morphotype A. flavus did not produce aflatoxins. These atoxigenic L-morphotype fungi were characterized using molecular markers. Several atoxigenic genotypes were detected across the country and could be used as biocontrol agents. The results from the current study hold promise for developing aflatoxin management strategies centered on biocontrol for use in Burundi to reduce aflatoxin contamination throughout the value chain.

Reduction of aflatoxins during brewing of a Malawian maize-based non-alcoholic beverage, thobwa.

This study reportsonthe effect of various production steps on levelsofaflatoxins during preparation of thobwa, a traditional maize-based fermented non-alcoholic beverage, brewed across Malawi. The effect of boiling, fermentation and their interaction on the level of aflatoxins, the trends of aflatoxin reduction during brewing, and the distribution of aflatoxins between the solid and liquid phases of the beverage were studied using VICAM AflaTest immunoaffinity fluorometric assay. Fermenting and boiling thobwapre-mix-, with initial aflatoxin content of 45-183 μg/kg, resulted in aflatoxin reduction of 47% (13-61 μg/kg)onaverage. Fermentation and boiling contributed about 20 and 33% aflatoxin reduction, respectively, but without interactive effect between the two factors. Fermenting the thobwafor 24 h led to further reduction of aflatoxins to about 37%oftheinitialcontent, andremainedconstant for up to 8 days.Thobwa is a popular beverage in Malawi which is consumed in large quantities by all gender categories including infants, therefore the presence of aflatoxins may constitute a significant health risk factor. This study highlights the need to use raw materials with low levels of aflatoxins for production of maize-based non-alcoholic beverages to ensure consumer safety.

Evaluation of Agronomic Characteristics, Disease Incidence, Yield Performance, and Aflatoxin Accumulation among Six Peanut Varieties (Arachis hypogea L.) Grown in Kenya.

Diseases contribute to attainment of less than 50% of the local groundnut potential yield in Kenya. This study aimed to evaluate the agronomic characteristics (flowering and germination), disease incidence, yield performance (biomass, harvest index, 100-pod, 100-seed, and total pod weight), and aflatoxin accumulation in six peanut varieties. A field experiment was conducted using four newly improved peanut varieties: CG9, CG7, CG12, and ICGV-SM 90704 (Nsinjiro), and two locally used varieties: Homabay local (control) and 12991, and in a randomized complete block design with three replications. The disease identification followed the International Crop Research Institute for the Semi-Arid Tropics (ICRISAT) rating scale and further isolation of fungal contaminants was conducted by a direct plating technique using potato dextrose agar. The aflatoxin levels in the peanuts were determined after harvesting using the ultrahigh performance liquid chromatography and fluorescence detection (UHPLC-FLD) technique. ICGV-SM 90704 showed the least average disease incidence of 1.31 ± 1.75%, (P < 0.05); the lowest total aflatoxin levels (1.82 ± 1.41 μg kg-1) with a range 0.00-0.85 μg kg-1 for total aflatoxins and a range 0.00-1.24 μg kg-1 for Aflatoxin B1. The locally used varieties (12991 and the control) revealed the highest disease incidence (5.41 ± 8.31% and 7.41 ± 1.88%), respectively. ICGV-SM 90704 was the best performing among all the six varieties with an average total pod weight (9.22 ± 1.19 kg), 100-pod weight (262.93 ± 10.8 g), and biomass of (27.21 ± 5.05 kg) per row. The 12991 variety and the control showed the least total pod weight (1.60 ± 0.28 and 1.50 ± 1.11 kg, respectively) (P = 0.0001). The newly improved varieties showed lower disease rates, low levels of aflatoxins, and higher yields than the locally used varieties.

The effect of harvest, sorting and drying practices on aflatoxin contamination of maize

Aflatoxins are the result of fungal metabolites that contaminate agricultural produce and can cause death to both humans and animals. The risks of using contaminated food and feed with aflatoxins have increased due to environmental factors, pre-harvest, post-harvest and socio-economic factors. This study revealed on harvesting, drying, and sorting practices that can reduce aflatoxin contamination. Experiments were designed in three districts; Kilosa, Gairo, and Mvomero with five (5) treatments replicated nine (9) times under farmers’ conditions. Samples were collected during harvesting, drying, and sorting; and analyzed for aflatoxin B1 using High Performance Liquid Chromatography (HPLC) at Tanzania Bureau of Standards (TBS) laboratory. Analysis of variance and comparison of means for moisture content, mold levels, grain damage, and aflatoxin levels were performed using GenStat® Executable release 16 Statistical Analysis Software. Results indicated that aflatoxin contamination levels were lower at maize grain harvested into bags (456.9μg/kg) compared to maize harvesting onto the ground (889.1μg/kg). It was also observed that maize dried on tarpaulin and raised platform had significantly (p&lt;0.05) low aflatoxin levels (65.5 μg/kg, 67.1μg/kg respectively) while maize dried on the ground had higher aflatoxin infestation (179 μg/kg). Again, sorting maize by color significantly (p&lt;0.05) reduces aflatoxin contamination. These results indicate that proper postharvest management of maize, such as harvesting maize on bags, drying maize on tarpaulin, raised platform and sorting maize by color gives the lowest aflatoxin contamination levels. Hence, proper education to farmers on harvesting maize using container/bags and drying maize on raised platform to be established in farmer level.

The One Nutrition in Complex Environments (ONCE) study protocol: a cluster-randomized multi-level multi-sectoral intervention to improve nutrition in Uganda

ObjectiveTo implement and measure the effects of a multi-level multi-sectoral social behavior change (SBC) intervention in Agago District of Northern Uganda and to determine the potential for scale-up.InterventionCompare the Nutrition Impact and Positive Practice (NIPP) approach to a NIPP+ approach. The NIPP approach involves nutrition education and SBC, whereas the NIPP+ adds agricultural inputs, training, and tools to support improved farm and water quality practices. The intervention effect will be measured through lower levels of aflatoxin in grain, lower water contamination, and improved knowledge on nutrition and health.DesignThis is a three-arm cluster-randomized controlled superiority trial (cRCT). The study arms include the following: group 1: NIPP; group 2: NIPP+, and group 3: control. Groups 1 and 2 will receive a 12-week intervention (NIPP or NIPP+) with active monitoring and longitudinal follow-up at 2, 6, and 12 months post-intervention. Additionally, an in-depth process and performance evaluation of each intervention arm will be undertaken using quantitative and qualitative methods. A total of 60 clusters from 5 subcounties of the Agago district will be randomly selected, and 15 households per cluster will be recruited using specific inclusion/exclusion criteria for a total of 900 households (300/arm). Respondents for the qualitative portion will be purposely selected.AnalysisWe will collect data from all participants at 3 time points: baseline, endline, and 12 months post-intervention. The analysis will utilize intent-to-treat (ITT) using the initial randomization of the treatment arms to determine the overall impact of having the NIPP vs. NIPP+ vs. control. Mixed effects models will be used to determine the role of time-variant and invariant individual household, and community characteristics, as well as measures of exposure and integration on key outcome indicators. A difference-in-difference analysis (baseline/endline, baseline/12 months post-intervention, endline/12 months post-intervention) will also be used to triangulate findings.Trial registrationNCT04209569. One Nutrition in Complex Environments (ONCE) Registered 24 December 2019

Aflatoxin in feedstuffs and raw milk in Republic of North Macedonia, occurrence and assessment

The main objective of this research is to estimate the situation of occurance of aflatoxins in feedstuffs and aflatoxin M1 raw cow`s milk in Republic of North Macedonia. Detected average concentrations of total aflatoxins in the examined period 2014-2017 were below legal prescribed level. Within the official monitoring programme in the country, 1718 samples of raw cow's milk have been analyzed during 2017 and 2018. Comparison of the data showed that the number of examined samples with values for aflatoxin M1 above the allowed limits, according to the regulation is in 2018 (10 samples) and 2017 (5 samples). Additionally, the calculation of exposure assessment of the human population in North Macedonia demonstrated that the exposure to AFM1 of the adult population in N. Macedonia for 2017 is 0.0563 ng/kg bw/daily, and for 2018 is 0.0824 ng/kg bw/daily. The calculated hazard index (HI) In both years, was lower than one, which means that there are no significant health risks for the consumers. It is important to have continuously low levels of aflatoxins in animal feed and nutrition, especially that the climate changes create more favorable conditions for the development of moulds of Aspergillus.

Does Use of Atoxigenic Biocontrol Products to Mitigate Aflatoxin in Maize Increase Fumonisin Content in Grains?

In the tropics and subtropics, maize (Zea mays) and other crops are frequently contaminated with aflatoxins by Aspergillus flavus. Treatment of crops with atoxigenic isolates of A. flavus formulated into biocontrol products can significantly reduce aflatoxin contamination. Treated crops contain up to 100% fewer aflatoxins compared with untreated crops. However, there is the notion that protecting crops from aflatoxin contamination may result in increased accumulation of other toxins, particularly fumonisins produced by a few Fusarium species. The objective of this study was to determine if treatment of maize with aflatoxin biocontrol products increased fumonisin concentration and fumonisin-producing fungi in grains. Over 200 maize samples from fields treated with atoxigenic biocontrol products in Nigeria and Ghana were examined for fumonisin content and contrasted with maize from untreated fields. Apart from low aflatoxin levels, most treated maize also harbored fumonisin levels considered safe by the European Union (<1 part per million; ppm). Most untreated maize also harbored equally low fumonisin levels but contained higher aflatoxin levels. In addition, during one year, we detected considerably lower Fusarium spp. densities in treated maize than in untreated maize. Our results do not support the hypothesis that treating crops with atoxigenic isolates of A. flavus used in biocontrol formulations results in higher grain fumonisin levels.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

Evaluation of reduction of aflatoxins by near infrared spectrometric sorting in the highly aflatoxin-contaminated peanut lots

Peanuts are one of the most susceptible crops to aflatoxigenic fungi, such as Aspergillus flavus and Aspergillus parasiticus, and is often contaminated with aflatoxins (AFs). AF contamination of peanuts is a major human and animal health hazard that has an economic impact worldwide. Numerous control and management strategies have been developed to reduce the levels of AFs in peanuts and sorting is the final stage in the process targeted at decreasing AF levels. Previous studies have shown that handpicking and electric color sorting are not entirely effective in reducing AF levels because of the occurrence of apparently healthy but internally moldy kernels with high AF levels. A previous study (Hirano, et al. 1998) showed that near infrared (NIR), the ratio of transmittance energies at two wavelengths of 700 to 1100, was applicable for efficiently removing internally moldy kernels. However the use of this procedure was limited to a sample that contained artificially inoculated kernels and low levels of AFs. This present study evaluated the performance of spectrometric sorting in naturally and highly AF-contaminated peanut lots on a commercial scale. The NIR spectrometric sorting clearly showed that AFs could be effectively decreased to levels of < 10 μg/kg even when the lot was highly contaminated with > 700 μg/kg of AFs by rejecting deteriorated kennels, including those that were internally moldy.

Properties of Grain Corn During Short Term Storage in Tropical Ambient Temperature

Grain corn in nature possesses a tendency to absorb and release moisture even during storage. Grain respiration will lead to fungal growth, consequently mycotoxin development and decreased nutritional components. Storage in tropical weather like Malaysia, in which the temperature is constantly hot throughout the year (temperature 23–33°C, with relative humidity around 81%) will promote further spoilage to the stored grain corn. Therefore, this paper discussed the properties of grain corn during three months of storage in a Malaysian weather setting. Grain corn with the initial moisture content of 12.5± 0.02% MC bagged in the; a) woven polypropylene jumbo bags, b) woven propylene 40 kg bag and c) plastic sealed container was stored in two different storage facilities located in MARDI for three months. The grain corn after three months of storage showed a consistent water activity, a darkening value in Chroma index, within the permissible limit of fungal growth and exhibits insect pest development of two major species of Coleoptera family. Grain corn is considered safe after three months of storage because low aflatoxin levels have been found, but the physical structure has been compromised due to insect pest infestations.

Application of the Biolog® Identification System for Aflatoxin-Producing Fungi Associated with Maize (Zea mays L.) Contamination in Romania

Cereals are very susceptible to fungal attacks. Fungi have a unique biochemical pathway to assimilate a vast array of available substrates and produce toxic secondary metabolites, such as mycotoxins, which represent a clear public health concern. In this context, a maize survey was conducted in order to assess the diversity of mycotoxin-producing fungi. Low levels of total aflatoxins, acceptable by the European Union, were detected in maize samples. A semi-automated Biolog® Microbial Identification System was used for the identification of the fungal strains. Enzyme-linked immunosorbent assay (ELISA) was used for the quantification of total aflatoxins. The results indicated that Fusarium udum and Rhizopus oryzae were the prevalent fungi for the assessed maize samples, while both control and treated samples showed low levels of total aflatoxins, which did not exceed 1.5 μg kg-1. The registered total aflatoxin concentrations were consistent with the European regulations.

Nutritive Value and Inherent Anti-Nutritive Factors in Processed Peanut (&lt;i&gt;Arachis hypogaea&lt;/i&gt;)

Processing conditions and even the form of the food being processed as they affect nutrient availability is critical to develop structured foods to meet the nutritional needs of end users. The effect of heat treatments (roasting, boiling and autoclaving) on the physical, nutritional and functional properties of in-shell and shelled peanut (Arachishypogaea) was determined. Unprocessed shelled peanut served as the control. Nutrient and anti-nutrient compositions of peanut samples were determined by standard methods, while physical (colour) and functional properties were also carried out. Analysis of variance was used to analyze the treatment groups and Duncan's multiple range tests to determine significant difference at p≤0.05. The result of proximate composition revealed that raw peanut had protein (32.7%), ash (1.37%), fibre (5.15%), fat (42.9%) and carbohydrate (12.1%). However, processing methods significantly increased the fat and ash contents. Peanut is high in calcium, magnesium and potassium but low in iron and zinc; processing significantly increased the elemental concentration of peanut. Phytate, tannin, oxalate, alkaloid, trypsin inhibitor and flavonoid were determined in the peanut samples and all were significantly affected by the processing method employed. However, boiling of shelled peanut was more effective in reducing the anti-nutrients than roasting and autoclaving. The aflatoxin concentration was in a range of 2.06-8.05 ppb. Shelled peanuts subjected to the processing methods had lower aflatoxin levels compared with in-shell processed peanuts. There exist variation in bulk densities (packed and loosed), water and oil absorption capacities as a result of processing method employed. The colour of peanut was significantly affected by the processing method. In general, processing of shelled peanut resulted in flour with better nutritional quality and functionality than in-shell peanut. The findings showed that boiling has proved to be an efficient method in processing of peanut.

Low Aflatoxin Levels in Aspergillus flavus-Resistant Maize Are Correlated With Increased Corn Earworm Damage and Enhanced Seed Fumonisin.

Preharvest mycotoxin contamination of field-grown crops is influenced not only by the host genotype, but also by inoculum load, insect pressure and their confounding interactions with seasonal weather. In two different field trials, we observed a preference in the natural infestation of corn earworm (CEW; Helicoverpa zea Boddie) to specific maize (Zea mays L.) genotypes and investigated this observation. The field trials involved four maize lines with contrasting levels of resistance to Aspergillus flavus. The resistant lines had 7 to 14-fold greater infested ears than the susceptible lines. Seed aflatoxin B1 (AF) levels, in mock- and A. flavus-inoculated ears were consistent with genotype resistance to A. flavus, in that the resistant lines showed low levels of AF (<30 ppb), whereas the susceptible lines had up to 500 ppb. On the other hand, CEW infestation showed a positive correlation with seed fumonisins (FUM) contamination by native Fusarium verticillioides strains. We inferred that the inverse trend in the correlation of AF and FUM with H. zea infestation may be due to a differential sensitivity of CEW to the two mycotoxins. This hypothesis was tested by toxin-feeding studies. H. zea larvae showed decreasing mass with increasing AF in the diet and incurred >30% lethality at 250 ppb. In contrast, CEW was tolerant to fumonisin with no significant loss in larval mass even at 100 ppm, implicating the low seed aflatoxin content as a predominant factor for the prevalence of CEW infestation and the associated fumonisin contamination in A. flavus resistant maize lines. Further, delayed flowering of the two resistant maize lines might have contributed to the pervasive H. zea damage of these lines by providing young silk for egg-laying. These results highlight the need for integrated strategies targeting mycotoxigenic fungi as well as their insect vectors for enhanced food safety.

The Impact of Bt Corn on Aflatoxin-Related Insurance Claims in the United States

Previous field studies have reached no collective consensus on whether Bt corn, one of the most commonly planted transgenic crops worldwide, has significantly lower aflatoxin levels than non-Bt isolines. Aflatoxin, a mycotoxin contaminating corn and other commodities, causes liver cancer in humans and can pose severe economic losses to farmers. We found that from 2001–2016, a significant inverse correlation existed between Bt corn planting and aflatoxin-related insurance claims in the United States, when controlling for temperature and drought. Estimated benefits of aflatoxin reduction resulting from Bt corn planting are about $120 million to $167 million per year over 16 states on average. These results suggest that Bt corn use is an important strategy in reducing aflatoxin risk, with corresponding economic benefits. If the same principles hold true in other world regions, then Bt corn hybrids adapted to diverse agronomic regions may have a role in reducing aflatoxin in areas prone to high aflatoxin contamination, and where corn is a dietary staple.

Immunological and pathological adverse effects of avian influenza virus subtype H9N2 infection in aflatoxicated-broiler chickens

Aflatoxin B1 (AFB1) is a metabolic product of the Aspergillus spp. of molds, which grow on several feedstuffs stored in hot moist conditions. It is one of the immunosuppressive agents that might influence the pathogenesisof avian influenza virus (AIV) subtype H9N2 in broilers, which can exacerbate the disease outcomes. The immunological, biochemical and pathological adverse health effects of an interaction between low levels of dietary aflatoxins (AFs) and H9N2 infection in broiler chickens were investigated. One hundred and eighty of unvaccinated 1-day-old COBB chicks were, therefore, raised for 35 days in the following treatment groups: control, AFs, AFs+H9N2, and H9N2. AFs in the basal diet was added at 200 ppb starting from the first day of age, while H9N2 virus was intra-nasally installed at a dose of 100 μl of 106 EID50/bird of allantois fluid at 23rd day. Humoral and cell-mediated immune responses were evaluated. Evidence of H9N2-AIV viral shedding was also detected. It has been observed that concurrent exposure of AFs and H9N2 virus negatively affected chicken performance traits i.e. lowered feed intake and body weights with exaggerated respiratory and digestive disturbances, and 20% mortality rate. Ten days’ post H9N2 infection, significant (p≤ 0.05) increment in serum transaminases (AST and ALT) and falling in cell-mediated immunity i.e. total leukocyte count, lymphocyte transformation activity and macrophage phagocytic activity were detected. Additionally, AFs+H9N2 significantly (p≤ 0.05) lowered H9N2-HI titers (5.5 Log2) than H9N2 alone (6.3 Log2). Pathologically, aflatoxicated chickens showed hydropic degeneration, hepatocytic vacuolation and necrosis of liver tissues with nephrosis and urates deposition in ureters, as well as bursal and thymic lesions, which were potent in H9N2–inoculated chickens. AFs exposure increased the incidence and titer of H9N2 viral shedding. It could be concluded that dietary contamination with AFs even at very low levels has explanatory effect in H9N2–inoculated broilers, and vice versa.

Discrimination of aflatoxin B1 contaminated pistachio kernels using laser induced fluorescence spectroscopy

Aflatoxin contamination of pistachio is one of the most significant issues related to its quality. The conventional ultraviolet (UV) induced fluorescence spectroscopy method of assessment is difficult to use for the screening of samples contaminated with low levels of aflatoxin due to its weak signal intensity and the interference of background constituents. Laser induced fluorescence spectroscopy (LIFS) technique is a highly sensitive and specific approach which has been successfully used to determine of the trace compounds in agricultural products. In this study, the feasibility of classifying aflatoxin B1 (AFB1) contamination in 250 kernels of two pistachio varieties (“Wanlong”, WL and “Hengkang”, HK) using LIFS was investigated. Four low concentration AFB1 solutions (5, 10, 20, and 50 ppb) were artificially applied on the surface of the kernels. The contaminated pistachios presented lower fluorescence intensity in the range 400 nm–610 nm when compared to uncontaminated control kernels. Principal component analysis (PCA) showed a pattern of separation between uncontaminated and contaminated kernels. Similar accuracy (92.3%–100%) was found in both varieties using a support vector machine (SVM) technique, indicating that changes in variety or kernel type are unlikely to have an influence on classification accuracy. Good discriminant ability (accuracy ≥ 98.4%) was achieved for AFB1 contamination of the pooled samples based on a combination of the standard normal variate (SNV) and the second derivative. Although these preliminarily results demonstrated that it is feasible to screen pistachios artificially contaminated with low concentration of AFB1 by LIFS, further work is necessary to test the performance of the LIFS method for detecting naturally contaminated samples.

Participatory evaluation of groundnut planting methods for pre-harvest aflatoxin management in Eastern Province of Zambia

Aflatoxin contamination remains a major challenge for smallholder groundnut producers in Southern Africa. This is compounded by the stringent aflatoxin regulatory regimes in the lucrative international markets that continue to deny groundnuts produced in this region the access to markets. Participatory on-farm experiments were carried in 2016 and 2017 in Chinkhombe (Katete) and Kalichero (Chipata), and on-station trials at Mount Makulu Central Research Station (Chilanga) to evaluate the efficacy of groundnut planting methods: planting in double rows, single rows, tied ridges and on flatbeds, for pre-harvest aflatoxin management. Planting on flatbeds (no ridges), a popular planting method in most parts of Zambia was designated as the baseline. Significantly low (p &lt; 0.05) levels of aflatoxin, (10.3 ± 3.1 μg/kg) were recorded in the groundnuts planted on tied ridges, and less than 22% of these had aflatoxin levels above the Zambia regulatory limit of 10 μg/kg, compared to more than 40% in other methods. Except for double rows, significantly higher pod yield, 1193 kg/ha, was recorded in groundnuts planted on tied ridges compared to other pre-harvest management options. A reduction of 37 and 81% in aflatoxin contamination was observed in groundnuts planted on single rows and tied ridges, respectively compared to an increase of 39.2% in double rows above 54.3 ± 10.9 μg/kg recorded in flatbeds. In addition, tied ridging was observed to improve plant vigour, lower disease incidence, insect pest and weed infestation. It is clear that the evaluation of these practices on-farm enabled more farmers to be more aware of the effects of these methods and get motivated to adopt them. It is thus imperative that participatory on-farm evaluations of existing aflatoxin management options are carried out as they are an essential step in influencing adoption and uptake of pre-harvest management control methods among smallholder farmers.

Perennial and seasonal contamination of maize by aflatoxins in eastern Kenya

BackgroundAflatoxin contamination of grain is a major constraint to sustained quality cereal production. The causative fungi, Aspergillus species infect crops in the field and continue to do so post-harvest where they produce toxins in store. The current study aimed at establishing seasonal variation in levels and types of aflatoxins in maize from the Eastern region of Kenya- the hot-spot for aflatoxicosis. Maize kernels were collected from farmers’ households in May and December 2013 -2 months after long rain and short rain season respectively. The total aflatoxins were quantified using Enzyme-Linked Immunosorbent Assay (ELISA), while the toxin composition was determined using Thin-Layer Chromatography (TLC) and confirmed using High-Performance Liquid Chromatography (HPLC).ResultsGenerally, grain harvested after the long rains (May) had significantly (p = 0.019) lower aflatoxin levels and variation (5.68 ± 6.31 ppb, 100% Aflatoxin B1) than that of short rains (10.77 ± 10.14 ppb, 72% AFB1). Additionally, from the long and short rain seasons, the samples exceeding regulatory allowed limit (10 ppb) were 16 and 44% respectively.ConclusionIn Eastern Kenya, consumption of maize harvested in the long rain season presents a recurrent risk of exposure to low levels of AFB1; while consumption of maize harvested after the short rain season presents a risk of seasonal exposure to high levels and mixed type of toxins However, this long term risk of exposure to aflatoxins is poorly documented hence these findings necessitate mitigation measures because AFB1– is a potent class 1 mutagenic toxin likely to cause liver cancer.

Dissection of mechanisms of resistance toAspergillus flavus and aflatoxin using tropical maize germplasm

Aspergillus flavus induced ear rots and subsequent contamination of maize (Zea mays L.) by aflatoxin is a serious food safety issue, especially in developing countries where the crop is mostly cultivated by smallholder famers for own consumption and income generation. A better understanding of the mechanisms of resistance could help breeders to develop resistant maize varieties. In this study, a set of six tropical maize inbred lines previously identified as resistant or susceptible under natural field conditions were evaluated for response toA. flavus colonisation and aflatoxin contamination. Fungal biomass was significantly higher (P&lt;0.05) in susceptible than resistant maize inbred lines, and this was highly correlated (P=0.001) to aflatoxin levels. Maize inbred lines MRI, MR2 and MR3 had low fungal biomass and low aflatoxin levels, suggesting that resistance in these lines was mediated through restricted fungal colonisation and establishment. Among the three putatively resistant inbred lines mentioned above, MR2 had a relatively high colonisation compared to the other two lines, revealing thatA. flavus could establish and colonise kernels that were injured during inoculation, but did not contain high levels of aflatoxin. This could signify the presence of host genes that interfere with the aflatoxin biosynthetic pathway.