Comprehensive assessment of maize aflatoxin levels in Eastern Kenya, 2005-2007

Association between low maternal serum aflatoxin B1 exposure and adverse pregnancy outcomes in Mombasa, Kenya, 2017-2019: A nested matched case-control study

We examined the association between serum aflatoxin B1-lysine adduct (AFB1-lys) levels in pregnant women and adverse pregnancy outcomes (low birthweight, miscarriage and stillbirth) through a nested matched case-control study of pregnant women enroled at ≤28 weeks' gestation in Mombasa, Kenya, from 2017 to 2019. Cases comprised women with an adverse birth outcome, defined as either delivery of a singleton infant weighing <2500 g, or a miscarriage, or a stillbirth, while controls were women who delivered a singleton live infant with a birthweight of ≥2500 g. Cases were matched to controls at a ratio of 1:2 based on maternal age at enrolment, gestational age at enrolment and study site. The primary exposure was serum AFB1-lys. The study included 125 cases and 250 controls. The median gestation age when serum samples were collected was 23.0 weeks (interquartile range [IQR]: 18.1-26.0) and 23.5 (IQR: 18.1-26.5) among cases and controls, respectively. Of the 375 tested sera, 145 (38.7%) had detectable serum AFB1-lys: 36.0% in cases and 40.0% in controls. AFB1-lys adduct levels were not associated with adverse birth outcomes on multivariable analysis. Mid-upper arm circumference was associated with a 6% lower odds of adverse birth outcome for every unit increase (p = 0.023). Two-fifths of pregnant women had detectable levels of aflatoxin midway through pregnancy. However, we did not detect an association with adverse pregnancy outcomes, likely because of low serum AFB1-lys levels and low power, restricting meaningful comparison. More research is needed to understand the public health risk of aflatoxin in pregnant women to unborn children.

Aflatoxins in maize and groundnuts on markets in Accra and consumers risk

This study presents the results of aflatoxin contamination of maize and groundnuts in major markets in Accra and assesses the population's exposure to aflatoxins. Raw maize and groundnuts from 6 major markets in Accra were sampled and analysed for their aflatoxin content. A total of 92 samples comprising 48 maize and 44 groundnuts were analysed using high-performance liquid chromatography, after extraction with methanol/water and cleanup on an immunoaffinity column. Total aflatoxins were quantified in 98% of the maize samples and 70% of the groundnut samples, with concentrations ranging from 0.60 to 1065 µg/kg and 0.20 to 627 µg/kg, respectively. Exposure assessment showed an estimated daily intake of 0.436 μg/kg bw/day and 0.0632 μg/kg bw/day for maize and groundnut consumption, respectively, suggesting significant health risks for consumers. The high prevalence and concentrations of aflatoxins call for an urgent need for measures to control exposure of the Ghanaian population.

A mixed methods assessment of knowledge, attitudes and practices related to aflatoxin contamination and exposure among caregivers of children under 5 years in western Kenya

OBJECTIVE

Identifying factors that may influence aflatoxin exposure in children under 5 years of age living in farming households in western Kenya.

DESIGN

We used a mixed methods design. The quantitative component entailed serial cross-sectional interviews in 250 farming households to examine crop processing and conservation practices, household food storage and consumption and local understandings of aflatoxins. Qualitative data collection included focus group discussions (N 7) and key informant interviews (N 13) to explore explanations of harvesting and post-harvesting techniques and perceptions of crop spoilage.

SETTING

The study was carried out in Asembo, a rural community where high rates of child stunting exist.

PARTICIPANTS

A total of 250 female primary caregivers of children under 5 years of age and thirteen experts in farming and food management participated.

RESULTS

Study results showed that from a young age, children routinely ate maize-based dishes. Economic constraints and changing environmental patterns guided the application of sub-optimal crop practices involving early harvest, poor drying, mixing spoiled with good cereals and storing cereals in polypropylene bags in confined quarters occupied by humans and livestock and raising risks of aflatoxin contamination. Most (80 %) smallholder farmers were unaware of aflatoxins and their harmful economic and health consequences.

CONCLUSIONS

Young children living in subsistence farming households may be at risk of exposure to aflatoxins and consequent ill health and stunting. Sustained efforts to increase awareness of the risks of aflatoxins and control measures among subsistence farmers could help to mitigate practices that raise exposure.

The synergistic effect of titanium dioxide nanoparticles and yeast isolated from fermented foods in reduction of aflatoxin B1

The presence of aflatoxins in food products can lead to health risks in human societies. Therefore, in the present study, the effect of yeast strains isolated from fermented products and titanium dioxide nanoparticles (TiO2-NPs) was studied on aflatoxin reduction. Yeast strains were isolated from fermented products such as sweet fruits and dairy products and identified using biochemical, ascospore (testing by culture medium optimization V8 which is called V8NLF), and molecular methods. The probiotic activity of four selected yeasts was evaluated. Then, the effect of selected yeast isolates and TiO2-NPs on reducing aflatoxin B1 (AFB1) in the medium was studied by measuring AFB1 using ELISA and HPLC. The results of biochemical and molecular identification experiments indicate that the selected strain (Y1) is Saccharomyces cerevisiae. The selected strains showed good tolerance to different concentrations of bile salt, pH, and NaCl, indicating appropriate probiotic activity. It also showed antimicrobial activity against Escherichia coli, Shigella dysenteriae, and Salmonella typhimurium. Selected strain and TiO2-NPs showed AFB1 reducing activity in the medium and when combined, showed synergistic effects in reducing AFB1. TiO2-NPs in combination with selected yeast strains have a high ability to remove AFB1 from the medium and, therefore, can be used for future studies.

Aspergillus flavus and Fusarium verticillioides and Their Main Mycotoxins: Global Distribution and Scenarios of Interactions in Maize

Maize is frequently contaminated with multiple mycotoxins, especially those produced by Aspergillus flavus and Fusarium verticillioides. As mycotoxin contamination is a critical factor that destabilizes global food safety, the current review provides an updated overview of the (co-)occurrence of A. flavus and F. verticillioides and (co-)contamination of aflatoxin B1 (AFB1) and fumonisin B1 (FB1) in maize. Furthermore, it summarizes their interactions in maize. The gathered data predict the (co-)occurrence and virulence of A. flavus and F. verticillioides would increase worldwide, especially in European cold climate countries. Studies on the interaction of both fungi regarding their growth mainly showed antagonistic interactions in vitro or in planta conditions. However, the (co-)contamination of AFB1 and FB1 has risen worldwide in the last decade. Primarily, this co-contamination increased by 32% in Europe (2010-2020 vs. 1992-2009). This implies that fungi and mycotoxins would severely threaten European-grown maize.

Dietary aflatoxin exposure of lactating mothers of children 0-6 months in Makueni County, Kenya

The southeastern region of Kenya is prone to aflatoxin outbreaks, yet maternal and infant aflatoxin intake levels remain unclear. We determined dietary aflatoxin exposure of 170 lactating mothers breastfeeding children aged 6 months and below in a descriptive cross-sectional study involving aflatoxin analysis of maize-based cooked food samples (n = 48). Their socioeconomic characteristics, food consumption patterns and postharvest handling of maize were determined. Aflatoxins were determined using high-performance liquid chromatography and enzyme-linked immunosorbent assay. Statistical analysis was conducted using Statistical Package Software for Social Sciences (SPSS version 27) and Palisade's @Risk software. About 46% of the mothers were from low-income households, and 48.2% had not attained the basic level of education. A generally low dietary diversity was reported among 54.1% of lactating mothers. Food consumption pattern was skewed towards starchy staples. Approximately 50% never treated their maize, and at least 20% stored their maize in containers that promote aflatoxin contamination. Aflatoxin was detected in 85.4% of food samples. The mean of total aflatoxin was 97.8 μg/kg (standard deviation [SD], 57.7), while aflatoxin B1 was 9.0 μg/kg (SD, 7.7). The mean dietary intake of total aflatoxin and aflatoxin B1 was 7.6 μg/kg/b.w.t/day (SD, 7.5) and 0.6 (SD, 0.6), respectively. Dietary aflatoxin exposure of lactating mothers was high (margin of exposure < 10,000). Sociodemographic characteristics, food consumption patterns and postharvest handling of maize variably influenced dietary aflatoxin exposure of the mothers. The high prevalence and presence of aflatoxin in foods of lactating mothers are a public health concern and calls for the need to devise easy-to-use household food safety and monitoring measures in the study area.

Drivers of Post-Harvest Aflatoxin Contamination: Evidence Gathered from Knowledge Disparities and Field Surveys of Maize Farmers in the Rift Valley Region of Kenya

Maize-dependent populations in sub-Saharan Africa are continually exposed to aflatoxin poisoning owing to their regular consumption of this dietetic cereal. Being a staple in Kenyan households, consumption of maize-based meals is done almost daily, thereby exposing consumers to aflatoxicoses. This study assessed awareness levels, knowledge disparities, and perceptions regarding aflatoxin contamination at the post-harvest phase among farmers in the Rift Valley Region of Kenya. Households were randomly selected using a geographical positioning system (GPS) overlay of the agro-ecological zones within Uasin Gishu and Elgeyo Marakwet counties. Face-to-face interviews were conducted in 212 smallholder and large-scale farms. The study documented the demographic profiles of farmers and knowledge, awareness, and perceptions of aflatoxin contamination using a pre-designed structured questionnaire. Most farmers were familiar with aflatoxins and the adverse effects they present to health (61.32%). Almost all the farmers (94.37%) were aware of storage molds and food-spoilage fungi. However, few farmers adopted good post-harvest practices (PHPs), such as avoiding premature harvests (49.8%), using well-ventilated storage spaces (44.6%), grain sorting (30.5%), proper drying of maize (17.8%), and using hermetic bags for storage (30.5%). Conclusively, intensified farmer education is required to train farmers on good PHPs to protect their maize from aflatoxigenic fungi and aflatoxin accumulation.

Effects of probiotic supplementation on very low dose AFB1-induced neurotoxicity in adult male rats

AIMS

Aflatoxin B1 (AFB1) is the most toxic and common form of AF found in food and feed. Although AFB1 exposure has toxic effects on many organs, studies on the brain are limited. Moreover, to the best of our knowledge, there is no study on the effect of probiotics on AFB1-induced neurotoxicity. Therefore, we aimed to evaluate the possible effects of probiotics on AFB1-induced neurotoxicity in the brain.

MAIN METHODS

Thirty-two adult male Wistar rats were divided into four groups: Vehicle (VEH), Probiotic (PRO) (2.5 × 10¹⁰ CFU/day VSL#3, orally), Aflatoxin B1 (AFB1) (25 μg/kg/week AFB1, orally), and Aflatoxin B1 + Probiotic (AFB1 + PRO) (2.5 × 10¹⁰ CFU/day VSL#3 + 25 μg/kg/week AFB1, orally). At the end of eight weeks, rats were behaviorally evaluated by the open field test, novel object recognition test, and forced swim test. Then, oxidative stress and inflammatory markers in brain tissues were analyzed. Next, brain sections were processed for Hematoxylin&Eosin staining and NeuN and GFAP immunostaining.

KEY FINDINGS

Probiotic supplementation tended to decrease oxidative stress and inflammatory markers compared to the AFB1 group. Besides, brain tissues had more normal histological structures in VEH, PRO, and AFB1 + PRO groups than in the AFB1 group. Moreover, in probiotic groups, GFAP immunoreactivity intensity was decreased, while NeuN-positive cell number increased in brain tissues compared to the AFB1 group.

SIGNIFICANCE

Probiotics seem to be effective at reducing the neurotoxic effects of AFB1. Thus, our study suggested that especially Bifidobacterium and Lactobacillus species can improve AFB1-induced neurotoxicity with their antioxidant and anti-inflammatory effects.

Mycotoxin Regulatory Status in Africa: A Decade of Weak Institutional Efforts

Food safety problems are a major hindrance to achieving food security, trade, and healthy living in Africa. Fungi and their secondary metabolites, known as mycotoxins, represent an important concern in this regard. Attempts such as agricultural, storage, and processing practices, and creation of awareness to tackle the menace of fungi and mycotoxins have yielded measurable outcomes especially in developed countries, where there are comprehensive mycotoxin legislations and enforcement schemes. Conversely, most African countries do not have mycotoxin regulatory limits and even when available, are only applied for international trade. Factors such as food insecurity, public ignorance, climate change, poor infrastructure, poor research funding, incorrect prioritization of resources, and nonchalant attitudes that exist among governmental organisations and other stakeholders further complicate the situation. In the present review, we discuss the status of mycotoxin regulation in Africa, with emphasis on the impact of weak mycotoxin legislations and enforcement on African trade, agriculture, and health. Furthermore, we discuss the factors limiting the establishment and control of mycotoxins in the region.

Determinants of aflatoxin exposures in Kenyan School-aged children

Aflatoxins are naturally occurring food toxins known to contaminate cereals with a carry-over effect in milk and meat products from farm animals raised on contaminated feed. In children, continuous consumption of aflatoxin-contaminated food is linked to immune suppression, vaccine interference and growth faltering while in adult populations, carcinogenesis in the liver has been established. We evaluate the main determinants of aflatoxin exposures among children recruited from primary schools in Makueni and Siaya Counties. A five-part questionnaire was administered to collect information from randomly selected participants. AflatoxinB₁-lysine adducts in children's sera and total aflatoxins in food samples were analyzed by High-Performance Liquid Chromatography with Fluorescence detection. Using Chi-squared tests and Kruskal-Wallis tests, children from low-income households had the highest aflatoxin exposure, p-value = 0.0029. Smaller family size, greater food diversity, and good farming practices were associated with low aflatoxin exposures p < 0.001. Individual households living under severe levels of poverty were evidently exposed to higher levels of aflatoxins.

Review of good agricultural practices for smallholder maize farmers to minimise aflatoxin contamination

Maize is consumed world-wide as staple food, livestock feed, and industrial raw material. However, it is susceptible to fungal attack and at risk of aflatoxin contamination under certain conditions. Such contamination is a serious threat to human and animal health. Ensuring that the maize used by food industry meets standards for aflatoxin levels requires significant investment across the supply chain. Good Agricultural Practices (GAP) form a critical part of a broader, integrated strategy for reduction of aflatoxin contamination. We reviewed and summarised the GAP of maize that would be effective and practicable for aflatoxin control within high-risk regions for smallholder farmers. The suggested practicable GAP for smallholder farmers were: use of drought-tolerant varieties; timely harvesting before physiological maturity; sorting to remove damaged ears and those having poor husk covering; drying properly to 13% moisture content; storage in suitable conditions to keep the crop clean and under condition with minimally proper aeration, or ideally under hermetic conditions. This information is intended to provide guidance for maize growers that will help reduce aflatoxin in high-risk regions, with a specific focus on smallholder farmers. Following the proposed guidelines would contribute to the reduction of aflatoxin contamination during pre-harvest, harvest, and post-harvest stages of the maize value chain.

Management strategies for aflatoxin risk mitigation in maize, dairy feeds and milk value chains—case study Kenya

Widespread aflatoxin contamination of a great number of food and feed crops has important implications on global trade and health. Frequent occurrence of aflatoxin in maize and milk poses serious health risks to consumers because these commodities are staple foods in many African countries. This situation calls for development and implementation of rigorous aflatoxin control measures that encompass all value chains, focusing on farms where food and feed-based commodities prone to aflatoxin contamination are cultivated. Good agricultural practices (GAP) have proven to be an effective technology in mitigation and management of the aflatoxin risk under farm conditions. The prevailing global climate change is shown to increase aflatoxin risk in tropical and subtropical regions. Thus, there is an urgent need to devise and apply novel methods to complement GAP and mitigate aflatoxin contamination in the feed, maize and milk value chains. Also, creation of awareness on aflatoxin management through training of farmers and other stakeholders and enforcement of regular surveillance of aflatoxin in food and feed chains are recommended strategies. This literature review addresses the current situation of aflatoxin occurrence in maize, dairy feeds and milk produced and traded in Kenya and current technologies applied to aflatoxin management at the farm level. Finally, a case study in Kenya on successful application of GAP for mitigation of aflatoxin risk at small-scale farms will be reviewed.

Mycotoxins contamination of market maize and the potential of density sorting in reducing exposure in unregulated food systems in Kenya

Aflatoxins and fumonisins commonly contaminate key food staples in tropical countries, causing recurring acute and chronic public health problems. The present study was conducted to assess the potential of a simple device designed for density-based sorting of maize for its potential to reduce aflatoxins and fumonisins in diverse samples of naturally contaminated maize. A cross sectional survey was conducted, analysing market maize samples (n=204) from eight counties in Western Kenya. A quarter (25%) of the maize samples were contaminated with aflatoxin B1 above the legal limit of 5 μg/kg and nearly half (48%) were contaminated with fumonisins at levels above the legal limit of 2 μg/g. Analysis of additional samples (n=24) from Meru County showed that contamination of maize with the two toxins was also common in Eastern Kenya. A simple density sorter was used to separate grain samples into heavy and light fractions. With an out-sort rate of 31%, density sorting was effective in separating maize by bulk density and 100-kernel weight (P<0.001). Bulk density was negatively correlated with aflatoxins in unsorted (r=-0.20, P<0.01) and heavy fractions (r=-0.32, P<0.01). Density sorting was effective at reducing fumonisins; for maize samples with >1 μg/g, the heavy (accepted) fraction had 66% lower fumonisins than the unsorted maize. After density sorting, the light and heavy fractions fumonisin levels differed by an average of 8.38 μg/g (P<0.001). However, sorting was not effective at significantly reducing aflatoxin levels in maize that was highly contaminated. A simple density sorting equipment that could be adopted by local small-scale millers has potential to reduce fumonisins in maize. Additional and complementary sorting technologies, such as size screening and spectral sorting might improve the effectiveness of reducing aflatoxins in maize.

Improved Sample Selection and Preparation Methods for Sampling Plans Used to Facilitate Rapid and Reliable Estimation of Aflatoxin in Chicken Feed

Aflatoxin B1 (AFB1), a toxic fungal metabolite associated with human and animal diseases, is a natural contaminant encountered in agricultural commodities, food and feed. Heterogeneity of AFB1 makes risk estimation a challenge. To overcome this, novel sample selection, preparation and extraction steps were designed for representative sampling of chicken feed. Accuracy, precision, limits of detection and quantification, linearity, robustness and ruggedness were used as performance criteria to validate this modification and Horwitz function for evaluating precision. A modified sampling protocol that ensured representativeness is documented, including sample selection, sampling tools, random procedures, minimum size of field-collected aggregate samples (primary sampling), procedures for mass reduction to 2 kg laboratory (secondary sampling), 25 g test portion (tertiary sampling) and 1.3 g analytical samples (quaternary sampling). The improved coning and quartering procedure described herein (for secondary and tertiary sampling) has acceptable precision, with a Horwitz ratio (HorRat = 0.3) suitable for splitting of 25 g feed aliquots from laboratory samples (tertiary sampling). The water slurring innovation (quaternary sampling) increased aflatoxin extraction efficiency to 95.1% through reduction of both bias (-4.95) and variability of recovery (1.2-1.4) and improved both intra-laboratory precision (HorRat = 1.2-1.5) and within-laboratory reproducibility (HorRat = 0.9-1.3). Optimal extraction conditions are documented. The improved procedure showed satisfactory performance, good field applicability and reduced sample analysis turnaround time.

Multiple Mycotoxins in Kenyan Rice

Multiple mycotoxins were tested in milled rice samples (n = 200) from traders at different milling points within the Mwea Irrigation Scheme in Kenya. Traders provided the names of the cultivar, village where paddy was cultivated, sampling locality, miller, and month of paddy harvest between 2018 and 2019. Aflatoxin, citrinin, fumonisin, ochratoxin A, diacetoxyscirpenol, T2, HT2, and sterigmatocystin were analyzed using ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS). Deoxynivalenol was tested using enzyme-linked immunosorbent assay (ELISA). Mycotoxins occurred in ranges and frequencies in the following order: sterigmatocystin (0–7 ppb; 74.5%), aflatoxin (0–993 ppb; 55.5%), citrinin (0–9 ppb; 55.5%), ochratoxin A (0–110 ppb; 30%), fumonisin (0–76 ppb; 26%), diacetoxyscirpenol (0–24 ppb; 20.5%), and combined HT2 + T2 (0–62 ppb; 14.5%), and deoxynivalenol was detected in only one sample at 510 ppb. Overall, low amounts of toxins were observed in rice with a low frequency of samples above the regulatory limits for aflatoxin, 13.5%; ochratoxin A, 6%; and HT2 + T2, 0.5%. The maximum co-contamination was for 3.5% samples with six toxins in different combinations. The rice cultivar, paddy environment, time of harvest, and millers influenced the occurrence of different mycotoxins. There is a need to establish integrated approaches for the mitigation of mycotoxin accumulation in the Kenyan rice.

The Scourge of Aflatoxins in Kenya: A 60-Year Review (1960 to 2020)

Aflatoxins are endemic in Kenya. The 2004 outbreak of acute aflatoxicosis in the country was one of the unprecedented epidemics of human aflatoxin poisoning recorded in mycotoxin history. In this study, an elaborate review was performed to synthesize Kenya’s major findings in relation to aflatoxins, their prevalence, detection, quantification, exposure assessment, prevention, and management in various matrices. Data retrieved indicate that the toxins are primarily biosynthesized by Aspergillus flavus and A. parasiticus, with the eastern part of the country reportedly more aflatoxin-prone. Aflatoxins have been reported in maize and maize products (Busaa, chan’gaa, githeri, irio, muthokoi, uji, and ugali), peanuts and its products, rice, cassava, sorghum, millet, yams, beers, dried fish, animal feeds, dairy and herbal products, and sometimes in tandem with other mycotoxins. The highest total aflatoxin concentration of 58,000 μg/kg has been reported in maize. At least 500 acute human illnesses and 200 deaths due to aflatoxins have been reported. The causes and prevalence of aflatoxins have been grossly ascribed to poor agronomic practices, low education levels, and inadequate statutory regulation and sensitization. Low diet diversity has aggravated exposure to aflatoxins in Kenya because maize as a dietetic staple is aflatoxin-prone. Detection and surveillance are only barely adequate, though some exposure assessments have been conducted. There is a need to widen diet diversity as a measure of reducing exposure due to consumption of aflatoxin-contaminated foods.

Nutrition and growth outcomes are affected by aflatoxin exposures in Kenyan children

Aflatoxin exposure, malnutrition and growth impairment in children present significant public health problems in low- and middle-income countries. Recent epidemiology studies show that exposure to aflatoxins through dietary sources in early life contributes to growth retardation among children. However, the findings remain inconclusive due to limited comparative studies in high versus low aflatoxin exposure regions. This cross-sectional study presents aflatoxin exposure levels among children aged 6 to 12 years, and further evaluates the association between aflatoxin exposure levels, malnutrition and growth impairment in Kenya, East Africa. AFB₁-lysine adducts are validated biomarkers of exposure and were quantified using HPLC with fluorescence detection. All children (n = 746) had detectable levels of AFB₁-lysine adducts in serum, range 0.65-518.9 pg/mg albumin with a geometric mean (GM) of 10.5 (95%CI 9.4-11.7) pg/mg albumin. The Geometric Means (GM) of AFB₁-lysine adducts were 14.0 (95%CI 12.5, 15.7) pg/mg albumin and 8.2 (95%CI 7.6, 8.8) pg/mg albumin (p-value < 0.001), among children recruited from Makueni and Siaya Counties, respectively. While the study confirms higher human exposure levels in Makueni county, it provides an initial data set for aflatoxin exposure levels among children recruited from Siaya County. In multivariate analysis, after adjusting for socio-economic indicators, farming practices, and household dietary patterns, increasing one unit of log AFB₁-lysine was associated with decreasing Weight-for-age z-score (WAZ) by -0.13, p-value = 0.019 among all children aged 6-12 years. Among children 6 to 9 years, WAZ decreases by -0.11 (-0.54, -0.01), p-value = 0.049. Additional growth parameters Height-for-age z-score (HAZ) and Weight-for-height z-score (WHZ) do not reach statistical significance. HAZ decreases by -0.08, p-value = 0.337 and WHZ decreases by -0.17, p-value = 0.437 with every increase in log AFB₁-lysine. These data suggest that efforts must be put in place to control for aflatoxin exposure in order to achieve better growth outcomes.

Assessment of willingness-to-pay for Aflasafe KE01, a native biological control product for aflatoxin management in Kenya

Contamination of key staples with aflatoxins compromises the quality of food and feed, impedes trade, and negatively affects the health of consumers whereas acute exposure can be fatal. This study used the Contingent Valuation Method (CVM) on a sample of 480 farmers in counties prone to aflatoxin contamination to assess the willingness to pay (WTP) by farmers for Aflasafe KE01, a promising biological control product for the management of aflatoxin contamination of key staples in Kenya, compare its cost with that of a similar product in use in Nigeria, and determine factors likely to affect its adoption. Four hundred and eighty households from four counties identified as aflatoxin hotspots in Kenya were purposively selected and interviewed using a semi-structured questionnaire. The mean WTP per kilogram of Aflasafe KE01, using Contingent Valuation Method in the four counties ranged from Kenya Shillings (Ksh) 113 to 152/kg compared to a cost of Ksh. 130/kg, the price of a similar product, Aflasafe^TM, in Nigeria. Factors that positively influenced farmers' WTP included information from crop extension services and access to credit. To facilitate the adoption of Aflasafe KE01 or any other biocontrol product in Kenya and elsewhere, there is a need for increased education efforts through extension services to farmers about aflatoxins. Strategies to ensure that the biocontrol product is integrated into the credit scheme of the technological packages to farmers need to be considered.

Aflatoxins: Producing-Molds, Structure, Health Issues and Incidence in Southeast Asian and Sub-Saharan African Countries

This review aims to update the main aspects of aflatoxin production, occurrence and incidence in selected countries, and associated aflatoxicosis outbreaks. Means to reduce aflatoxin incidence in crops were also presented, with an emphasis on the environmentally-friendly technology using atoxigenic strains of Aspergillus flavus. Aflatoxins are unavoidable widespread natural contaminants of foods and feeds with serious impacts on health, agricultural and livestock productivity, and food safety. They are secondary metabolites produced by Aspergillus species distributed on three main sections of the genus (section Flavi, section Ochraceorosei, and section Nidulantes). Poor economic status of a country exacerbates the risk and the extent of crop contamination due to faulty storage conditions that are usually suitable for mold growth and mycotoxin production: temperature of 22 to 29 °C and water activity of 0.90 to 0.99. This situation paralleled the prevalence of high liver cancer and the occasional acute aflatoxicosis episodes that have been associated with these regions. Risk assessment studies revealed that Southeast Asian (SEA) and Sub-Saharan African (SSA) countries remain at high risk and that, apart from the regulatory standards revision to be more restrictive, other actions to prevent or decontaminate crops are to be taken for adequate public health protection. Indeed, a review of publications on the incidence of aflatoxins in selected foods and feeds from countries whose crops are classically known for their highest contamination with aflatoxins, reveals that despite the intensive efforts made to reduce such an incidence, there has been no clear tendency, with the possible exception of South Africa, towards sustained improvements. Nonetheless, a global risk assessment of the new situation regarding crop contamination with aflatoxins by international organizations with the required expertise is suggested to appraise where we stand presently.

Postharvest Storage Practices of Maize in Rift Valley and Lower Eastern Regions of Kenya: A Cross-Sectional Study

An assessment of local farmers' knowledge, attitude, and practices on postharvest maize storage and management was carried out with a view of understanding its role in maize contamination with mycotoxins and postharvest losses in Rift Valley and Lower Eastern Regions of Kenya among 165 and 149 farmers, respectively. Differences between the two regions were analyzed using the Chi-square test, Fisher exact test, and two-sample t-test. The median quantity of maize harvested by farmers in the two regions after shelling was 585 kg. A median of 20 kg of maize was put aside as a result of rotting before shelling, and there was a significant mean difference in maize set aside as a result of rotting between the two regions (107.88 kg vs. 31.96 kg; t (306.25) = 5.707, P value <0.001). The quantity of discoloured and mouldy maize consumed ranged from 0 to 90 kg; 7 (2.2%) respondents consumed mouldy maize, 36 (11.5%) fed it to cows, and 19 (6.1%) fed it to poultry. A small percentage (3.5%) believed mouldy maize is safe for human consumption, 23.6% for animal consumption, while 15.0% considered it safe for brewing, with the differences between the two regions being statistically significant (P value <0.05). Nearly half of the respondents (48.4%) kept maize on cobs indoors, 47.1% left it in the field without covering, and 33.1% consumed and sold maize while still green, with more farmers from Lower Eastern practicing this. The results of the study suggest that there were poor postharvest practices and low awareness levels among maize farmers and that this can lead to postharvest losses due to Fusarium spp. infection and mycotoxin contamination that poses a threat to human and animal food safety. This calls for interventions on better postharvest practices.

Variation in Occurrence and Aflatoxigenicity of Aspergillus flavus from Two Climatically Varied Regions in Kenya

Aflatoxins are carcinogenic chemical metabolites produced by Aspergillus spp. of the section Flavi. In Kenya, Aspergillus flavus is the most prevalent and has been associated with several acute and chronic aflatoxin outbreaks in the past. In this study, we evaluated the occurrence of A. flavus in soils from two agro-ecological regions with contrasting climatic conditions, aflatoxin contamination histories and cropping systems. Aspergillus spp. were first isolated from soils before the identification and determination of their aflatoxigenicity. Further, we determined the occurrence of Pseudomonas and Bacillus spp. in soils from the two regions. These bacterial species have long been associated with biological control of several plant pathogens including Aspergillus spp. Our results show that A. flavus occurred widely and produced comparatively higher total aflatoxin levels in all (100%) study sites from the eastern to the western regions of Kenya. For the western region, A. flavus was detected in 4 locations (66.7%) that were previously under maize cultivation with the isolates showing low aflatoxigenicity. A. flavus was not isolated from soils under sugarcane cultivation. Distribution of the two bacterial species varied across the regions but we detected a weak relationship between occurrence of bacterial species and A. flavus. We discuss these findings in the context of the influence of climate, microbial profiles, cropping systems and applicability in the deployment of biological control remedies against aflatoxin contamination.

Aflatoxin exposure in children age 6-12 years: a study protocol of a randomized comparative cross-sectional study in Kenya, East Africa

Background

Aflatoxins (AFs) are naturally occurring fungal metabolites produced by the Aspergilla species of fungi. The staple food grain, maize (Zea mays), is highly susceptible to AF contamination. In Kenya, contamination of maize supplies by AFs is a recognized public health problem which has resulted in over 600 human deaths. Human exposure to AFs can occur in utero, via breast milk, through weaning foods, and throughout an individual’s lifetime. Recent epidemiological studies have shown that exposure to AFs in early life through diet is a contributing factor to immune suppression, micronutrient deficiency, possible vaccine interference, and impaired growth in children. However, these results remain inconsistent and inconclusive due to lack of randomized controlled studies.

Methods

A randomized school-based cross-sectional study was designed to study AF exposure levels and associated health effects in children between ages 6 and 12 years. Participants were recruited from primary schools within Siaya and Makueni Counties of Kenya, East Africa. The Joint Ethics Committee of the University of Nairobi and Kenyatta National Hospital in Kenya approved the research protocol and procedures for the study. Both parental consent and child assent were obtained before enrollment in the study. Parents were requested to provide household grain samples and fill out questionnaires detailing their sociodemographic information, household dietary patterns, farming practices, and knowledge of AF contamination. Blood samples were collected from children participants, and sera were prepared for analysis of AFB₁-lysine which is one of the validated biomarkers for AF exposure.

Discussion

This protocol describes a school-based, cross-sectional study whose objective is to comparatively evaluate the role of AF exposure on adverse health outcomes in children. Specifically, effects of cumulative AF exposure on nutritional status, immune markers, and growth parameters will be assessed.

Trial registration

This study is not a clinical trial, rather a cross-sectional study aimed at providing baseline data on AF exposures in children who live in presumably high versus low AF exposure regions. Results from the study can be used to design interventions and/or prospective cohort studies aimed at studying adverse health effects associated with cumulative AF exposure through diets. The study reference number is P741/12/2017 and registered with KNH-UoN Ethics and Research Committee.

Aflatoxin in household maize for human consumption in Kenya, East Africa

The objective of this study is to determine the occurrence and level of aflatoxins (AFs) contamination in freshly harvested maize for human consumption in rural Kenya. Maize kernels and freshly milled maize flour (n = 338) were collected from households in Siaya and Makueni counties. While both counties are representatives of different environmental and climate conditions, Makueni County is the area with reported outbreaks of aflatoxicosis. Samples were analysed for AFB₁, AFB₂, AFG₁, and AFG₂ using Ultra High-Pressure Liquid Chromatography with Fluorescence detection. AFs were detected in 100% of the samples with the range of 2.14-411 µg/kg. The geometric mean of total AFs in all samples from Makueni County is 62.5 μg/kg with 95% CI: 53.7, 71.4 while in Siaya County is 52.8 μg/kg with 95% CI: 44.0, 61.7. This study showed that AFs contamination is prevalent in maize-based foods in the region.

Occurrence of Fungi and Mycotoxins in Fish Feeds and Their Impact on Fish Health

The rapid population growth in developing countries has led to strong pressure on capture fisheries. However, capture fisheries have reached their maximal limits of fish production and are supplemented by farmed fish. The growth in aquaculture has led to high demand for fish feeds, which play a very important role in fish nutrition and health. Use of animal protein in fish feeds is expensive; hence, a majority of farmers from developing countries use local feed ingredients from plant origin as a source of dietary protein. However, these ingredients of plant origin provide the best natural substrates for fungi, which can be easily accompanied by mycotoxin development under suitable conditions. The locally made feed comprises ingredients such as soybeans, cottonseed cake, and wheat and maize bran which are mixed together and ground after which the compounded feed is pelleted and stored. Among the ingredients, maize and oilseeds are more susceptible for mycotoxigenic fungi compared to other ingredients. The outcomes of mycotoxin contamination in fish feeds are not different from other animal species intended for human consumption, and they are directly associated with production losses, particularly decreased weight gain and feed conversion, impaired immune system and reproductive performance, and increased fish mortality. Fish may also carry mycotoxin residues along the food chain, thus compromising human health. Hence, it is important to ensure the control of mycotoxin contamination in fish feeds, especially during the production and storage.

Occupational exposure to aflatoxins and health outcomes: a review

Aflatoxins [AFs] are secondary metabolites of the fungus species Aspergillus spp. Both animal and epidemiological studies provided sufficient evidence on the carcinogenic, immunotoxic, mutagenic, and genotoxic potential of AFs. While ingestion is the main route of exposure for AFs through consumption of contaminated food products, agricultural workers and personnel who handle AF-contaminated grains are also at higher risk of exposure via inhalation. The main objective of the review is to provide a comprehensive overview of past scientific studies on occupational exposure to AFs, high-risk occupations, and disease outcomes. A search of peer-reviewed articles was done on PubMed and Web of Science Databases. A total of 164 papers was identified and 61 journal articles were selected for further review. High risk occupations include animal husbandry and processing of grain cereals and/or animal feed. Primary liver cancer and respiratory cancers were the most reported as a result of occupational exposure to AFs. For future studies, improved study designs, better characterization of AFs exposure in an occupational setting, and use of biomarkers are recommended in order to promote better understanding of occupational exposure to AFs and the resulting disease burden among workers.

Post-harvest practices for aflatoxin control: Evidence from Kenya

We assess the impact of a package of post-harvest technologies on aflatoxin contamination of maize through a randomized trial in rural Kenya. Some elements of this package (training and provision of plastic sheets for sun-drying) were provided free of charge to all participants in treatment villages and were widely adopted. Others (a mobile drying service and hermetic storage bags) were provided free to a subset of randomly selected farmers in treatment villages while others had to pay. Overall, the intervention reduced aflatoxin contamination by over 50%. Most of this reduction appears to be due training and the use of drying sheets, the lowest-cost of all the technologies offered.

Enhancing Food Safety through Adoption of Long-Term Technical Advisory, Financial, and Storage Support Services in Maize Growing Areas of East Africa

Grain production and storage are major components in food security. In the ancient times, food security was achieved through gathering of fruits, grains, herbs, tubers, and roots from the forests by individual households. Advancements in human civilization led to domestication of crops and a need to save food for not only a household, but the nation. This extended need for food security led to establishment of national reservoirs for major produces and this practice varies greatly in different states. Each of the applied food production, handling, and storage approaches has its benefits and challenges. In sub-Saharan Africa, several countries have a public funded budget to subsidize production costs, to buy grains from farmers, and to store the produce for a specific period and/or until the next harvests. During the times of famine, the stored grains are later sold at subsidized prices or are given for free to the starving citizens. If there is no famine, the grain is sold to retailers and/or processors (e.g., millers) who later sell it to the consumers. This approach works well if the produce (mainly grain) is stored under conditions that do not favor growth of molds, as some of these microbes could contaminate the grain with toxic and carcinogenic metabolites called mycotoxins. Conditions that alleviate contamination of grains are required during production, handling, and storage. Most of the grain is produced by smallholder farmers under sub-optimal conditions, making it vulnerable to colonization and contamination by toxigenic fungi. Further, the grain is stored in silos at large masses, where it is hard to monitor the conditions at different points of these facilities, and hence, it becomes vulnerable to additional contamination. Production and storage of grain under conditions that favor mycotoxins poses major food health and safety risks to humans and livestock who consume it. This concept paper focuses on how establishment of a local grain production and banking system (LGPBS) could enhance food security and safety in East Africa. The concept of LGPBS provides an extension of advisory and finance support within warehouse receipt system to enhance grain production under optimal conditions. The major practices at the LGPBS and how each could contribute to food security and safety are discussed. While the concept paper gives more strength on maize production and safety, similar practices could be applied to enhance safety of other grains in the same LGPBS.

Pre-harvest management is a critical practice for minimizing aflatoxin contamination of maize

Maize, the main dietary staple in Kenya, is one of the crops most susceptible to contamination by aflatoxin. To understand sources of aflatoxin contamination for home grown maize, we collected 789 maize samples from smallholder farmers' fields in Eastern and South Western, two regions in Kenya representing high and low aflatoxin risk areas, respectively, and determined aflatoxin B1 (AFB1) using ELISA with specific polyclonal antibodies. AFB1 was detected in 274 of the 416 samples from Eastern Kenya at levels between 0.01 and 9091.8 μg kg-1 (mean 67.8 μg kg-1). In South Western, AFB1 was detected in 233 of the 373 samples at levels between 0.98 and 722.2 μg kg-1 (mean 22.3 μg kg-1). Of the samples containing AFB1, 153 (55.8%) from Eastern and 102 (43.8%) from South Western exceeded the maximum allowable limit of AFB1 (5 μg kg-1) in maize for human consumption in Kenya. The probable daily intake (PDI) of AFB1 in Eastern Kenya ranged from 0.07 to 60612 ng kg-1 bw day-1 (mean 451.8 ng kg-1 bw day-1), while for South Western, PDI ranged from 6.53 to 4814.7 ng kg-1 bw day-1 (mean 148.4 ng kg-1 bw day-1). The average PDI for both regions exceeded the estimated provisional maximum tolerable daily intake of AFB1, which is a health concern for the population in these regions. These results revealed significant levels of preharvest aflatoxin contamination of maize in both regions. Prevention of preharvest infection of maize by toxigenic A. flavus strains should be a critical focal point to prevent aflatoxin contamination and exposure.

Gut Microbiota Profiling of Aflatoxin B1-Induced Rats Treated with Lactobacillus casei Shirota

Aflatoxin B1 (AFB1) is a ubiquitous carcinogenic food contaminant. Gut microbiota is of vital importance for the host's health, regrettably, limited studies have reported the effects of xenobiotic toxins towards gut microbiota. Thus, the present study aims to investigate the interactions between AFB1 and the gut microbiota. Besides, an AFB1-binding microorganism, Lactobacillus casei Shirota (Lcs) was tested on its ability to ameliorate the changes on gut microbiota induced by AFB1. The fecal contents of three groups of rats included an untreated control group, an AFB1 group, as well as an Lcs + AFB1 group, were analyzed. Using the MiSeq platform, the PCR products of 16S rDNA gene extracted from the feces were subjected to next-generation sequencing. The alpha diversity index (Shannon) showed that the richness of communities increased significantly in the Lcs + AFB1 group compared to the control and AFB1 groups. Meanwhile, beta diversity indices demonstrated that AFB1 group significantly deviated from the control and Lcs + AFB1 groups. AFB1-exposed rats were especially high in Alloprevotella spp. abundance. Such alteration in the bacterial composition might give an insight on the interactions of AFB1 towards gut microbiota and how Lcs plays its role in detoxification of AFB1.

The impact of reducing dietary aflatoxin exposure on child linear growth: a cluster randomised controlled trial in Kenya

Introduction

Observational studies have documented an association between aflatoxin (AF) exposure and reduced linear growth in infants and young children. Our objective was to assess the effectiveness of reducing AF exposure on child linear growth and serum AF levels in rural areas in Eastern Kenya.

Methods

A cluster randomised controlled design was used (28 intervention and 28 control clusters). The intervention arm received a swapping (contaminated maize was replaced with safe maize) and a stockist intervention (households were encouraged to purchase from a stockist supplied with clean maize). Women in the fifth to final month of pregnancy were invited to enrol in the study. Outcomes were child length-for-age Z-score (LAZ), the prevalence of stunting and child serum AFB₁-lysine adduct level 24 (endline, primary outcomes) and 11 to 19 months (midline, secondary outcomes) after trial commencement, respectively. The trial was registered with socialscienceregistry.org.

Results

Of the 1230 unborn children enrolled in the study, 881 (72%) were included in the LAZ and 798 (65%) in the serum AFB₁ analysis. The intervention significantly reduced endline ln serum AFB₁-lysine adduct levels (intervention effect—0.273, 95% CI −0.547 to 0.001; one-sided p=0.025), but had no effect on endline LAZ or stunting (mean LAZ at endline was −1.64). At midline, the intervention increased LAZ by 0.16 (95% CI −0.009 to 0.33; one-sided p=0.032) and reduced stunting by seven percentage points (95% CI −0.125 to −0.007; one-sided p=0.015), but had no impact on serum AFB₁ levels.

Conclusion

Improving access to AF-free maize substantially reduced endline serum AF, but had no effect on child linear growth. The midline analysis suggests that AF may affect linear growth at younger ages.

Trial registration number

AEARCTR-0000105.

Occurrence of aflatoxin in agricultural produce from local markets in Burundi and Eastern Democratic Republic of Congo

Aflatoxins are noxious secondary metabolites, of certain fungal species, found in food and feed. Contamination of a commodity with aflatoxins is associated with production and storage losses, and subsequently less food availability. Aflatoxins can also pose human health risks and represent a barrier to the development of trade, in both domestic and international markets. In this study, samples of cassava, maize, groundnut, beans, soybean, sorghum and milk, and their processed products were collected from local markets in Burundi and Eastern DRC. In order to investigate the levels of aflatoxin, crop samples were analyzed using a single step lateral flow immunochromatographic assay (Reveal Q+), while enzyme‐linked immune‐sorbent assay (ELISA) was used to analyze aflatoxin‐M₁ in milk, yogurt, and cheese samples. The results revealed the presence of aflatoxins in all samples from both countries, with levels ranging from 1.3 to 2,410 μg/kg. Samples collected from Burundi contained relatively higher (p > 0.0.5) levels of aflatoxins. In 51% of all the crops samples, total aflatoxin contamination was above the EU maximum tolerable level of 4 μg/kg. Processed products, particularly from groundnut, maize, and sorghum, had the highest levels of aflatoxin contamination when compared to unprocessed grain. With regard to milk and dairy products, the level of aflatoxin‐M₁ ranged from 4.8 to 261.1 ng/kg. Approximately 29% of milk and yogurt samples had aflatoxin‐M₁ higher than the EU regulatory limit of 50 ng/kg, whereas 20% of cheese samples were found to be contaminated at levels higher than the maximum limit of 250 ng/kg. These results can serve as the basis for pre‐ and postharvest approaches to reduce aflatoxin contamination in agricultural commodities in Burundi and Eastern DRC in order to reduce health risk, avoid reduced production in livestock, and open up export markets.

Prevalence and mitigation of aflatoxins in Kenya (1960-to date)

Aflatoxins are highly toxic metabolites of several Aspergillus species widely distributed throughout the environment. These toxins have adverse effects on humans and livestock at a few micrograms per kilogram (μg/kg) concentrations. Strict regulations on the concentrations of aflatoxins allowed in food and feed exist in many nations in the developing world. Loopholes in implementing regulations result in the consumption of dangerous concentrations of aflatoxins. In Kenya, where 'farm-to-mouth' crops become severely contaminated, solutions to the aflatoxins problem are needed. Across the decades, aflatoxins have repeatedly caused loss of human and animal life. A prerequisite to developing viable solutions for managing aflatoxins is understanding the geographical distribution and severity of food and feed contamination, and the impact on lives. This review discusses the scope of the aflatoxins problem and management efforts by various players in Kenya. Economic drivers likely to influence the choice of aflatoxins management options include historical adverse health effects on humans and animals, cost of intervention for mitigation of aflatoxins, knowledge about aflatoxins and their impact, incentives for aflatoxins safe food and intended scope of use of interventions. It also highlights knowledge gaps that can direct future management efforts. These include: sparse documented information on human exposure; few robust tools to accurately measure economic impact in widely unstructured value chains; lack of long-term impact studies on benefits of aflatoxins mitigation; inadequate sampling mechanisms in smallholder farms and grain holding stores/containers; overlooking social learning networks in technology uptake and lack of in-depth studies on an array of aflatoxins control measures followed in households. The review proposes improved linkages between agriculture, nutrition and health sectors to address aflatoxins contamination better. Sustained public awareness at all levels, capacity building and aflatoxins related policies are necessary to support management initiatives.

Aflatoxin exposure assessed by aflatoxin albumin adduct biomarker in populations from six African countries: REVIEW ARTICLE

Aflatoxins are a group of carcinogenic mycotoxins that have been implicated to have other adverse health impacts, including child growth impairment and immune function suppression. Aflatoxin B₁ is the most toxic and most common of the aflatoxins. Contamination of various food crops is common in sub-Saharan Africa, particularly in staple crops such as maize and groundnuts, leading to chronic dietary exposure in many populations. For many years we have used the aflatoxin albumin adduct as a biomarker of aflatoxin exposure, assessed using a competitive inhibition enzyme linked immunosorbent assay (ELISA). Here, we review our recent studies of human exposure in six African countries; Gambia, Guinea, Kenya, Senegal, Tanzania and Uganda. This data shows the widespread exposure of vulnerable populations to aflatoxin. Geometric mean (95% confidence interval) levels of the biomarker ranged from 9.7 pg/mg (8.2, 11.5) in Ugandan children to 578.5 pg/mg (461.4, 717.6) in Kenyan adolescents during an acute aflatoxicosis outbreak year. We describe how various factors may have influenced the variation in aflatoxin exposure in our studies. Together, these studies highlight the urgent need for measures to reduce the burden of aflatoxin exposure in sub-Saharan Africa.

Aflatoxin B1 induced multiple epigenetic modulators in human epithelial cell lines

The compulsive and insidious secondary metabolite aflatoxin B₁, produced by the opportunistic fungi Aspergillus flavus, upholds a distinguished place in midst of the toxicants causing fatal hazards to humans. Aflatoxins alter the function of host cells by inducing multiple effects through genetic and non-genetic pathways. Epigenetic mechanisms drag major attention towards finding novel and new mechanisms involved in this process. Our present work intends to study the functional expression profile of multiple epigenetic regulators. AFB₁ modulates multiple epigenetic regulators like DNA methyltransferases (DMNTs), histones modifying enzymes and polycomb proteins. AFB₁ upregulates the expression of DNMTs at gene and protein level in a dose dependent manner. It reduced the histone acetyl transferase (HAT) activity significantly with a remarkable increase in histone deacetylase (HDAC) activity along with an induction in expression of HDACs gene and protein in a dose dependent manner. The gene and protein expression of polycomb repressor proteins B cell specific moloney murine leukemia virus integration site 1 (BMI-1) and enhancer of zeste homolog 2 (EZH2) was significantly over expressed with enhanced trimethylation of H3K27 and ubiquitination of H2AK119. In summary, our results show impact of aflatoxin B₁ on multiple epigenetic modulations known to be pivotal in oncogenic processes.

The Binding Efficiency and Interaction of Lactobacillus casei Shirota Toward Aflatoxin B1

The use of probiotic as dietary approach to prevent exposure to food contaminant, aflatoxin B1 (AFB1) has greatly increased. Several studies found that AFB1 binding to the bacterial cell wall is strain-specific. Moreover, the interaction between AFB1 and bacterial cell wall is not well-understood, thus warrants further investigation. This research was conducted to assess the ability of Lactobacillus casei Shirota (Lcs) to bind AFB1 at different concentrations and to determine AFB1 binding efficiency of different Lcs cell components including live cell, heat-treated, and cell wall. In addition, the interaction between AFB1 and Lcs was also evaluated via scanning electron microscopy (SEM) and through an animal study. The binding of AFB1 by all Lcs cell components depends on the concentration of available AFB1. Among all Lcs cell components, the live Lcs cells exhibited the highest binding efficiency (98%) toward AFB1. Besides, the SEM micrographs showed that AFB1 induced structural changes on the bacterial cell surface and morphology including rough and irregular surface along with a curve rod-shaped. In vivo experiment revealed that Lcs is capable to neutralize the toxicity of AFB1 on body weight and intestine through the binding process. The animal’s growth was stunted due to AFB1 exposure, however, such effect was significantly (p < 0.05) alleviated by Lcs. This phenomenon can be explained by a significant (p < 0.05) decreased level of blood serum AFB1 by Lcs (49.6 ± 8.05 ng/mL) compared to AFB1-exposed rats without treatment (88.12 ± 10.65 ng/mL). Taken together, this study highlights the potential use of Lcs as a preventive agent against aflatoxicosis via its strong binding capability.

Effect of High Protein Diet and Probiotic Lactobacillus casei Shirota Supplementation in Aflatoxin B1-Induced Rats

Probiotic Lactobacillus casei Shirota (LcS) is a potential decontaminating agent of aflatoxin B₁ (AFB₁). However, few studies have investigated the influence of diet, especially a high protein (HP) diet, on the binding of AFB₁ by probiotics. This research was conducted to determine the effect of HP diet on the ability of LcS to bind AFB₁ and reduce aflatoxin M₁ (AFM₁) in AFB₁-induced rats. Sprague Dawley rats were randomly divided into three groups: A (HP only), B (HP + 10⁸ CFU LcS + 25 μg AFB1/kg BW), and C (HP + 25 μg AFB1/kg BW). Levels of AST and ALP were higher in all groups but other liver function's biomarkers were in the normal range, and the liver's histology showed no structural changes. The urea level of rats in group B (10.02 ± 0.73 mmol/l) was significantly lower (p < 0.05) than that of rats in group A (10.82 ± 0.26 mmol/l). The presence of carcinoma in the small intestine and colon was more obvious in group C than in group B. Moreover, rats in group B had significantly (p < 0.05) lower AFM₁ concentration (0.39 ± 0.01 ng/ml) than rats in group C (5.22 ± 0.28 ng/ml). Through these findings, LcS supplementation with HP diet alleviated the adverse effects of AFB₁ by preventing AFB₁ absorption in the small intestine and reducing urinary AFM₁.

Elucidating Adverse Nutritional Implications of Exposure to Endocrine-Disrupting Chemicals and Mycotoxins through Stable Isotope Techniques

Multiple drivers of the double burden of malnutrition (DBM) include a rapid shift from predominantly plant-based diets to energy-dense foods based on meats, milk, animal fats and vegetable oils. The shift to overweight and obesity is driven by increased exposure to mass media, urbanization, technological advances in food processing, rising income and increased population density associated with increased access to cheap foods. At the same time, undernutrition persists mainly due to food insecurity and lack of access to safe water, sanitation and adequate health care. All known nutrition interventions result in only one third reduction in stunting. Little consideration has been given to hazardous exposure to endocrine disrupting chemicals (EDCs) and microbial toxins as major components of the malnutrition-causal framework. These hazards include microbial toxins, for example, mycotoxins, and environmental pollutants such as persistent organic pollutants (POPs), some of which are known to disrupt the endocrine system. These hazards sit at the cross road of undernutrition and overweight and obesity since the exposure cuts across the critical window of opportunity (the first 1000 days). In this review, we update on the role of food and environmental contaminants, especially EDCs and aflatoxins, in child growth and on the implications for metabolic dysfunction and disease risk in later life, and discuss potential applications of nuclear and isotopic techniques to elucidate the underlying biological mechanisms, outcome indicators, as well as occurrence levels.

Engaging One Health for Non-Communicable Diseases in Africa: Perspective for Mycotoxins

The role of mycotoxins-e.g., aflatoxins, ochratoxins, trichothecenes, zearalenone, fumonisins, tremorgenic toxins, and ergot alkaloids-has been recognized in the etiology of a number of diseases. In many African countries, the public health impact of chronic (indoor) and/or repeated (dietary) mycotoxin exposure is largely ignored hitherto, with impact on human health, food security, and export of African agricultural food products. Notwithstanding, African scientific research reached milestones that, when linked to findings gained by the international scientific community, make the design and implementation of science-driven governance schemes feasible. Starting from Nigeria as leading African Country, this article (i) overviews available data on mycotoxins exposure in Africa; (ii) discusses new food safety issues, such as the environment-feed-food chain and toxic exposures of food producing animals in risk assessment and management; (iii) identifies milestones for mycotoxins risk management already reached in West Africa; and (iv) points out preliminary operationalization aspects for shielding communities from direct (on health) and indirect (on trade, economies, and livelihoods) effects of mycotoxins. An African science-driven engaging of scientific knowledge by development actors is expected therefore. In particular, One health/One prevention is suggested, as it proved to be a strategic and sustainable development framework.

Vulnerability of global food production to extreme climatic events

It is known that the frequency, intensity or duration of the extreme climatic events have been changing substantially. The ultimate goal of this study was to identify current vulnerabilities of global primary food production against extreme climatic events, and to discuss potential entry points for adaptation planning by means of an explorative vulnerability analysis. Outcomes of this analysis were demonstrated as a composite index where 118 country performances in maintaining safety of food production were compared and ranked against climate change. In order to better interpret the results, cluster analysis technique was used as a tool to group the countries based on their vulnerability index (VI) scores. Results suggested that one sixth of the countries analyzed were subject to high level of exposure (0.45-1), one third to high to very high level of sensitivity (0.41-1) and low to moderate level of adaptive capacity (0-0.59). Proper adaptation strategies for reducing the microbial and chemical contamination of food products, soil and waters on the field were proposed. Finally, availability of data on food safety management systems and occurrence of foodborne outbreaks with global coverage were proposed as key factors for improving the robustness of future vulnerability assessments.

Adaptation and mitigation options to manage aflatoxin contamination in food with a climate change perspective

Understanding the impact of climate change remains vital for food safety and public health. Of particular importance is the influence of climatic conditions on the growth of Aspergillus flavus and production of their toxins. Nevertheless, little is known about the actual impact of climate change on the issue. Setting up of relevant measures to manage the impact has therefore become a daunting task especially in developing nations. Therefore, this study aimed at providing adaptation and mitigation options to manage this risk with a special focus on Kenya where cases of aflatoxicosis have been recurrent. We used a systematic literature review of review and research articles, with limited searching but systematic screening to explore available qualitative and quantitative data. Projections from the data, showed that on average, a 58.9% increase of aflatoxin contamination in the Central and Western parts and a decrease of 44.6% in the Eastern and Southern parts is expected but with several possible scenarios. This makes the impact of climate change on aflatoxin contamination in Kenya complex. To protect the public and environment from the negative impact, a regulatory framework that allows for an integrated management of aflatoxins in a changing climate was proposed. The management practices in the framework are divided into agronomic, post-harvest and institutional levels. Given the multiple points of application, coordination amongst stakeholders along the chain is fundamental. We therefore proposed a complimentary framework that allows the food safety issues to be addressed in an integrated manner while allowing for transparent synergies and trade-offs (in implementing the measures). A policy-oriented foresight should be carried out to provide policy based evidence for the applicability of the proposed adaptation and mitigation measures.

Aflatoxin B1 Induced Compositional Changes in Gut Microbial Communities of Male F344 Rats

Aflatoxins are a group of potent foodborne toxicants naturally occurring in maize and groundnuts. Differential species-specific sensitivity to aflatoxins has been documented but cannot be fully explained by the differences in metabolism of these toxicants among animal species. Commensal microbial communities (microbiota) are critical to human and animal health, but few studies have assessed interactions between xenobiotic toxins and those microbiota, and its potential effects to humans and animals. Here, an exploratory dosing experiment was conducted to explore effects of Aflatoxin B1 (AFB1) on the gut microbiota in a commonly used rat model. Male F344 rats were randomly divided into groups and treated with different concentrations of AFB1. Microbial communities in fecal samples were assessed using 16S rRNA sequence analysis. We found that samples from the control group had a phylogenetically diverse community, and that increasing AFB1 doses decreased this diversity but increased evenness of community composition. In addition, the gut microbiota from different samples was clustered according to their dosing regimens. There is no community shift at the phylum level but some lactic acid bacteria were significantly depleted by AFB1. These findings suggested that AFB1 could modify the gut microbiota in a dose-dependent manner.