Assessment of Aflatoxin and Fumonisin Contamination of Maize in Western Kenya

Processing complementary foods to reduce mycotoxins in a medium scale Tanzanian mill: A hazard analysis critical control point (HACCP) approach

Designing and implementing processing procedures for producing safe complementary foods in dynamic and unregulated food systems where common food staples are frequently contaminated with mycotoxins is challenging. This paper presents lessons about minimizing aflatoxins (AF) in groundnut flour and AF and/or fumonisins (FUM) in maize and groundnut pre-blended flour for complementary feeding in the context of a dietary research intervention in rural Tanzania. The flours were processed in collaboration with Halisi Products Limited (Halisi), a medium scale enterprise with experience in milling cereal-based flours in Arusha, Tanzania. Using a hazard analysis critical control point (HACCP) approach for quality assurance, two critical control points (CCPs) for AF in processing the pre-blended flour were identified: 1) screening maize before procurement, and 2) blending during the processing of each constituent flour. Blending of maize flour was also identified as a CCP for FUM. Visual inspection during screening and sorting were identified as important control measures for reducing AF, but these steps did not meet the criteria for a CCP due to lack of objective measurement and verifiable standards for AF. The HACCP approach enabled the production of low AF (<5 μg/kg) and FUM (<2 μg/g) flours with low rejection rates for the final products. The paper presents practical lessons that could be of value to a range of commercial processors in similar low- and middle-income contexts who are keen on improving food quality.

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.

Multispectral Sorting Based on Visibly High-Risk Kernels Sourced from Another Country Reduces Fumonisin and Toxigenic Fusarium on Maize Kernels

Fusarium species infect maize crops leading to the production of fumonisin by their toxigenic members. Elimination of microbes is critical in mitigating further postharvest spoilage and toxin accumulation. The current study investigates the efficacy of a previously described multispectral sorting technique to analyze the reduction of fumonisin and toxigenic Fusarium species found contaminating maize kernels in Kenya. Maize samples (n = 99) were collected from six mycotoxin hotspot counties in Kenya (Embu, Meru, Tharaka Nithi, Machakos, Makueni, and Kitui County) and analyzed for aflatoxin and fumonisin using commercial ELISA kits. Aflatoxin levels in majority (91%) of the samples were below the 10 ng/g threshold set by the Kenya Bureau of Standards and therefore not studied further. The 23/99 samples that had >2,000 ng/g of fumonisin were selected for sorting. The sorter was calibrated using kernels sourced from Ghana to reject visibly high-risk kernels for fumonisin contamination using reflectance at nine distinct wavelengths (470-1,550 nm). Accepted and rejected streams were tested for fumonisin using ELISA, and the presence of toxigenic Fusarium using qPCR. After sorting, there was a significant (p < 0.001) reduction of fumonisin, by an average of 1.8 log ng/g (98%) and ranging between 0.14 and 2.7 log ng/g reduction (28-99.8%) with a median mass rejection rate of 1.9% (ranged 0% to 48%). The fumonisin rejection rate ranged between 0 and 99.8% with a median of 77%. There was also a significant reduction (p = 0.005) in the proportion of DNA represented by toxigenic Fusarium, from a mean of 30-1.4%. This study demonstrates the use of multispectral sorting as a potential postharvest intervention tool for the reduction of Fusarium species and preformed fumonisin. The spectral sorting approach of this study suggests that classification algorithms based on high-risk visual features associated with mycotoxin can be applied across different sources of maize to reduce fumonisin.

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.

Label-Free Electrochemical Aptasensor Based on the Vertically-Aligned Mesoporous Silica Films for Determination of Aflatoxin B1

Herein we report a highly specific electrochemical aptasenseor for AFB1 determination based on AFB1-controlled diffusion of redox probe (Ru(NH₃)₆³⁺) through nanochannels of AFB1-specific aptamer functionalized VMSF. A high density of silanol groups on the inner surface confers VMSF with cationic permselectivity, enabling electrostatic preconcentration of Ru(NH₃)₆³⁺ and producing amplified electrochemical signals. Upon the addition of AFB1, the specific interaction between the aptamer and AFB1 occurs and generates steric hindrance effect on the access of Ru(NH₃)₆³⁺, finally resulting in the reduced electrochemical responses and allowing the quantitative determination of AFB1. The proposed electrochemical aptasensor shows excellent detection performance in the range of 3 pg/mL to 3 μg/mL with a low detection limit of 2.3 pg/mL for AFB1 detection. Practical analysis of AFB1 in peanut and corn samples is also accomplished with satisfactory results by our fabricated electrochemical aptasensor.

Underreported Human Exposure to Mycotoxins: The Case of South Africa

South Africa (SA) is a leading exporter of maize in Africa. The commercial maize farming sector contributes to about 85% of the overall maize produced. More than 33% of South Africa’s population live in rural settlements, and their livelihoods depend entirely on subsistence farming. The subsistence farming system promotes fungal growth and mycotoxin production. This review aims to investigate the exposure levels of the rural population of South Africa to dietary mycotoxins contrary to several reports issued concerning the safety of South African maize. A systematic search was conducted using Google Scholar. Maize is a staple food in South Africa and consumption rates in rural and urban communities are different, for instance, intake may be 1–2 kg/person/day and 400 g/person/day, respectively. Commercial and subsistence maize farming techniques are different. There exist differences influencing the composition of mycotoxins in food commodities from both sectors. Depending on the levels of contamination, dietary exposure of South Africans to mycotoxins is evident in the high levels of fumonisins (FBs) that have been detected in SA home-grown maize. Other potential sources of exposure to mycotoxins, such as carryover effects from animal products and processed foods, were reviewed. The combined effects between FBs and aflatoxins (AFs) have been reported in humans/animals and should not be ignored, as sporadic breakouts of aflatoxicosis have been reported in South Africa. These reports are not a true representation of the entire country as reports from the subsistence-farming rural communities show high incidence of maize contaminated with both AFs and FBs. While commercial farmers and exporters have all the resources needed to perform laboratory analyses of maize products, the greater challenge in combatting mycotoxin exposure is encountered in rural communities with predominantly subsistence farming systems, where conventional food surveillance is lacking.

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.

Fumonisins in African Countries

Maize and other cereals are the commodities most contaminated with fumonisins. The maize acreage is increasing in Africa, and the maize harvest provides important foods for humans and feeds for domestic animals throughout the continent. In North Africa, high levels of fumonisins have been reported from Algeria and Morocco, while low levels have been detected in the rather few fumonisin analyses reported from Tunisia and Egypt. The West African countries Burkina Faso, Cameroon, Ghana, and Nigeria all report high levels of fumonisin contamination of maize, while the few maize samples analysed in Togo contain low levels. In Eastern Africa, high levels of fumonisin contamination have been reported from the Democratic Republic of Congo, Ethiopia, Kenya, Tanzania, and Uganda. The samples analysed from Rwanda contained low levels of fumonisins. Analysis of maize from the Southern African countries Malawi, Namibia, South Africa, Zambia, and Zimbabwe revealed high fumonisin levels, while low levels of fumonisins were detected in the few analyses of maize from Botswana and Mozambique.

Validation of a HACCP community-based infants' complementary food safety assurance method in cash crop producing communities in Gedeo zone, Southern Ethiopia

A method based on a hazard analysis critical control point (HACCP)-based standard operating procedure (SOP) has been developed and implemented in community-based (CB) production of complementary foods (CFs) in agrarian regions in rural Ethiopia. The objective of this study was to validate the method in another setup, more specifically in cash crop (coffee and khat) producing communities in Southern Ethiopia. A quasi-experimental study was employed for the method validation. Two villages in the Gedeo zone, Southern Ethiopia were selected and a total of 40 mother-child pairs, 20 in each village, were involved in the study. Sociodemographic data, knowledge, and complementary feeding practices were collected using pretested questionnaires. The training was given to each mother for 1 h about community-based CFs production and implementation of the method. Then, 30 CF samples were collected and the level of aflatoxins (AFB1, AFB2, AFG1, and AFG2) was determined using a validated method. The majority (77.5%) of the mothers understand the importance of complementary feeding and give it to their infants beyond 6 months. Nearly two-thirds (62.5%) of the mothers had knowledge about the health impacts of aflatoxins, but the remaining 37.5% lacked awareness about the health risks of aflatoxins. Mothers were very well-motivated for the training and they promised to implement the knowledge and skill gained from the training for improving the nutritional status of their children. Overall, 23.3% of the CFs were contaminated by aflatoxins. AFB1 and AFG1 were detected in 6.7 and 16.7% of the CF samples, respectively. In cash crop-producing communities around the country, the HACCP-based SOP is easily validated in CB CFs production. Therefore, a scaleup of the method at the national level and beyond is recommended.

Incidence of toxigenic Aspergillus and Fusarium species occurring in maize kernels from Kenyan households

Aspergillus and Fusarium are fungal genera that include toxigenic and pathogenic species, able to suffuse farmers’ crops and secrete an array of small molecular weight secondary metabolites which can cause health complications to humans and animals when ingested. In sub-Sahara Africa, contamination and persistence of these fungi is increased by the tropical climatic conditions which are ideal for the fungi to thrive. This study evaluated the incidence, regional distribution and toxigenic potential of Aspergillus and Fusarium species occurring in maize kernels from Eastern, Western, Coastal and the Lake Victoria agro-ecological zones of Kenya. Maize kernels were collected from 16 households in each agro-ecological zone. Single spore technique was used to isolate pure cultures of Aspergillus and Fusarium which were identified morphologically. Further, molecular analysis was done using the internal transcribed spacer 1 (ITS 1) region of the ribosomal DNA for Aspergillus and the translation elongation factor-1 alpha (TEF-1α) for Fusarium. The potential of the isolated fungi to produce mycotoxins was probed by polymerase chain reaction (PCR) based on the aflatoxin regulatory aflaR gene in Aspergillus, and the fumonisin backbone structure gene FUM1 in Fusarium. Among the potentially aflatoxigenic A. flavus species isolated, 55% were from Eastern, 27% from the Coastal zone, 13% from Lake Victoria zone and 5% from Western Kenya. Among the potentially fumonisin producing F. verticillioides isolated, 45% were from the Lake Victoria agro-ecological zone, 30% were from Western, 15% from Eastern Kenya and 10% from the Coastal agro-ecological zone. This study adds data on potential mycotoxin hotspots in Kenya useful in employing targeted and regional mycotoxin mitigation strategies in efforts to avert future mycotoxicoses outbreaks in Kenya.

Comprehensive analysis of multiple mycotoxins and Aspergillus flavus metabolites in maize from Kenyan households

This study assessed the levels of mycotoxins in maize from Kenyan households. Further, local open pollinated maize varieties were compared with commercial hybrids to evaluate which variety is less susceptible to mycotoxin contamination. Four hundred and eighty (n = 480) maize samples were collected in the years 2018-2020 from households in Eastern, Western, Coastal and Lake Victoria regions of Kenya. Liquid chromatography coupled to tandem mass spectrometry was used to detect and quantify 22 mycotoxins, along with 31 Aspergillus flavus metabolites in the samples. Eastern Kenya had the highest aflatoxin (AF) contamination with 75% of samples having AF levels above the Kenyan regulatory limits (10 μg/kg), the highest concentration was 558.1 μg/kg. In Western Kenya, only 18% of samples had concentration levels above the Kenyan regulatory limits for AF with highest sample having 73.3 μg/kg. The Lake Victoria region had the most fumonisins (F) contamination, with 53% of the samples having fumonisin B₁ (FB₁) < 1000 μg/kg. However, only 20% of the samples surpassed the Kenyan regulatory limit for total fumonisins (2000 μg/kg) with the highest concentration being 13,022 μg/kg. In addition, 21.6% of samples from the Lake Victoria region had zearalenone (ZEN) and deoxynivalenol (DON) above regulatory limits for European countries (1000 μg/kg). Western region had the least A. flavus metabolites contamination (18%) while the Eastern region had the highest incidence of A. flavus metabolites (81%). Among the A. flavus metabolites, cyclopiazonic acid (CPA), beta-cyclopiazonic acid (β CPA), flavacol (FLV) and methylcitreo-isocoumarin (MIC) positively correlated with each other but negatively correlated with the other metabolites. Significant positive co-occurrence was also noted among Fusarium mycotoxins: nivalenol (NIV) positively correlated with DON (r = 0.81), fusarenon-X (FX) (r = 0.81) and ZEN (r = 0.70). Negative correlations were observed between Aspergillus and Fusarium mycotoxins: aflatoxin B₁ (AFB₁) negatively correlated with FB₁ (r = -0.11), FX (r = -0.17) and ZEN (r = -0.20). Local open-pollinated maize varieties (L-opv) were less susceptible to mycotoxin contamination compared to the commercial hybrids (C-hy). This study reveals that Kenyan maize is contaminated with multiple mycotoxins most of which are not regulated in Kenya despite being regulated in other parts of the world. A comprehensive legislation should therefore be put in place to protect the Kenyan public against chronic exposure to these mycotoxins. In addition to high yield, there is a need for commercial hybrid maize breeders to incorporate mycotoxin resistance as an important trait in germplasm improvement in seeds production.

The persistent threat of emerging plant disease pandemics to global food security

Plant disease outbreaks are increasing and threaten food security for the vulnerable in many areas of the world. Now a global human pandemic is threatening the health of millions on our planet. A stable, nutritious food supply will be needed to lift people out of poverty and improve health outcomes. Plant diseases, both endemic and recently emerging, are spreading and exacerbated by climate change, transmission with global food trade networks, pathogen spillover, and evolution of new pathogen lineages. In order to tackle these grand challenges, a new set of tools that include disease surveillance and improved detection technologies including pathogen sensors and predictive modeling and data analytics are needed to prevent future outbreaks. Herein, we describe an integrated research agenda that could help mitigate future plant disease pandemics.

The efficacy and effect on gut microbiota of an aflatoxin binder and a fumonisin esterase using an in vitro simulator of the human intestinal microbial ecosystem (SHIME®)

Mycotoxin intoxication is in general an acknowledged and tackled issue in animals. However, in several parts of the world, mycotoxicoses in humans still remain a relevant issue. The efficacy of two mycotoxin detoxifying animal feed additives, an aflatoxin bentonite clay binder and a fumonisin esterase, was investigated in a human child gut model, i.e. the in vitro Simulator of the Human Intestinal Microbial Ecosystem (SHIME®). Additionally, the effect of the detoxifiers on gut microbiota was examined in the SHIME. After an initial two weeks of system stabilisation, aflatoxin B1 (AFB1) and fumonisin B1 (FB1) were added to the SHIME diet during one week. Next, the two detoxifiers and mycotoxins were added to the system for an additional week. The AFB1, FB1, hydrolysed FB1 (HFB1), partially hydrolysed FB1a and FB1b concentrations were determined in SHIME samples using a validated ultra-performance liquid chromatography-tandem mass spectrometry method. The short-chain fatty acid (SCFA) concentrations were determined by a validated gas chromatography-mass spectrometry method. Colonic bacterial communities were analysed using metabarcoding, targeting the hypervariable V1-V3 regions of the 16S rRNA genes. The AFB1 and FB1 concentrations significantly decreased after the addition of the detoxifiers. Likewise, the concentration of HFB1 significantly increased. Concentrations of SCFAs remained generally stable throughout the experiment. No major changes in bacterial composition occurred during the experiment. The results demonstrate the promising effect of these detoxifiers in reducing AFB1 and FB1 concentrations in the human intestinal environment, without compromising the gastrointestinal microbiota.

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.

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.

Genetic Characterization of Fungal Biodiversity in Storage Grains: Towards Enhancing Food Safety in Northern Uganda

Worldwide fungal contamination leads to both quantitative and qualitative grain losses during crop growth and/or storage. A greater proportion of grains contamination with toxins often occurs in sub-Saharan Africa, where control measures are limited. We determined fungal diversity and their toxin production ability in household grains meant for human consumption to highlight the risk of mycotoxin exposure among people from northern Uganda. The study underlines the high diversity of fungi that group into 15 genera; many of which are plant pathogens with toxigenic potential. Fusarium verticillioides was the most common fungal species isolated from household grains. The study also indicates that northern Uganda is favored by a high proportion of toxigenic isolates of F. verticillioides, F. andiyazi, and F. proliferatum, which are characterized by a high fumonisins production capability. The fumonisins production ability was not dependent on the species, grain types, and haplotype group to which the isolates belong. The contamination of most household grains with fungi capable of producing a high amount of toxin shows that most people are exposed to an elevated amount of mycotoxins, which shows the frequent problems with mycotoxins that have been reported in most parts of sub-Saharan Africa.

The Influence of Weather on the Occurrence of Aflatoxin B1 in Harvested Maize from Kenya and Tanzania

A study was conducted using maize samples collected from different agroecological zones of Kenya (n = 471) and Tanzania (n = 100) during the 2013 maize harvest season to estimate a relationship between aflatoxin B1 concentration and occurrence with weather conditions during the growing season. The toxins were analysed by the ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method. Aflatoxin B1 incidence ranged between 0-100% of samples in different regions with an average value of 29.4% and aflatoxin concentrations of up to 6075 µg/kg recorded in one sample. Several regression techniques were explored. Random forests achieved the highest overall accuracy of 80%, while the accuracy of a logistic regression model was 65%. Low rainfall occurring during the early stage of the maize plant maturing combined with high temperatures leading up to full maturity provide warning signs of aflatoxin contamination. Risk maps for the two countries for the 2013 season were generated using both random forests and logistic regression models.

Effects of the Use of Good Agricultural Practices on Aflatoxin Levels in Maize Grown in Nandi County, Kenya

Aflatoxin contaminated maize is of public health concern in Kenya. Training farmers on good agricultural practice (GAP) has been touted as a mitigative measure. Little is known of the effect of such training on aflatoxin levels in maize grown in Kenya. This study evaluated what effect training farmers on GAP has on aflatoxin levels in maize grown in Kaptumo, Kilibwoni, and Kipkaren divisions in Nandi County. Ninety farmers were recruited for the study and interviewed on GAP. Maize samples were additionally collected from the participating farmers and analyzed for aflatoxins using competitive enzyme-linked immunosorbent assay (c-ELISA). All farmers prepared the land before planting, applied correct spacing between the planted crops, carried out weeding, cleaned their stores before use, checked the condition of the maize after harvesting, sorted maize after shelling, and knew about aflatoxins. The majority of the farmers (90%) used fertilizers, dried maize after harvesting, knew that aflatoxins were harmful to humans, and used clean transport in transporting the harvested maize. About 98% of farmers did stooking after harvesting and 97% used wooden pallets in the maize stores. The percentage of farmers who practiced early planting, top dressing, crop rotation, raising stores above the ground, applying insecticide after shelling and feeding damaged/rotten seeds to their animals was 84–96%, 62–80%, 67–85%, 86–98%, 63–81%, and 7–21% respectively. About 18/90 (20%) of all farmers reported that they had a relative who had died from liver cancer, and the mean aflatoxin levels in season 1 were significantly different from those in season 2 (1.92 ± 1.07 ppb; 1.30 ± 1.50 ppb). Our findings suggest that although training farmers to adopt good agricultural practices was observed to be efficient in mitigating the problem of aflatoxins, the receptiveness of farmers to different aspects of the training may have differed. Therefore, in designing an optimized regional aflatoxin contamination strategy, local applicability should be considered.

Exploring aflatoxin contamination and household-level exposure risk in diverse Indian food systems

The present study sought to identify household risk factors associated with aflatoxin contamination within and across diverse Indian food systems and to evaluate their utility in risk modeling. Samples (n = 595) of cereals, pulses, and oil seeds were collected from 160 households across four diverse districts of India and analyzed for aflatoxin B1 using enzyme-linked immunosorbent assay (ELISA). Demographic information, food and cropping systems, food management behaviors, and storage environments were profiled for each household. An aflatoxin detection risk index was developed based on household-level features and validated using a repeated 5-fold cross-validation approach. Across districts, between 30–80% of households yielded at least one contaminated sample. Aflatoxin B1 detection rates and mean contamination levels were highest in groundnut and maize, respectively, and lower in other crops. Landholding had a positive univariate effect on household aflatoxin detection, while storage conditions, product source, and the number of protective behaviors used by households did not show significant effects. Presence of groundnut, post-harvest grain washing, use of sack-based storage systems, and cultivation status (farming or non-farming) were identified as the most contributive variables in stepwise logistic regression and were used to generate a household-level risk index. The index had moderate classification accuracy (68% sensitivity and 62% specificity) and significantly correlated with village-wise aflatoxin detection rates. Spatial analysis revealed utility of the index for identifying at-risk localities and households. This study identified several key features associated with aflatoxin contamination in Indian food systems and demonstrated that household characteristics are substantially predictive of aflatoxin risk.

Effects of the Use of Good Agricultural Practices on Aflatoxin Levels in Maize Grown in Nandi County, Kenya

Aflatoxin contaminated maize is of public health concern in Kenya. Training farmers on good agricultural practice (GAP) has been touted as a mitigative measure. Little is known of the effect of such training on aflatoxin levels in maize grown in Kenya. This study evaluated what effect training farmers on GAP has on aflatoxin levels in maize grown in in maize grown in Kaptumo, Kilibwoni, and Kipkaren divisions in Nandi County. Ninety farmers were recruited for the study and interviewed on GAP. Maize samples were additionally collected from the participating farmers and analyzed for aflatoxins using competitive enzyme-linked immunosorbent assay (c-ELISA). All farmers prepared the land before planting, did correct spacing between the planted crops, carried out weeding, cleaned their stores before use, checked the condition of the maize after harvesting, sorted maize after shelling, and knew aflatoxins. A majority of the farmers (90%) used fertilizers, dried maize after harvesting, knew that aflatoxins were harmful to humans, and used clean transport in transporting the harvested maize. About 98% of farmers did stooking after harvesting and 97% used wooden pallets in the maize stores. The percentage of farmers who practiced early planting, top dressing, crop rotation, raising stores above the ground, applying insecticide after shelling and feeding damaged/rotten seeds to their animals was 84–96%, 62–80%, 67–85%, 86–98%, 63–81%, and 7–21% respectively. About 18/90 (20%) of all farmers reported that they had a relative who had died from liver cancer and the mean aflatoxin levels in season 1 were significantly different from season 2 (1.92 ± 1.07 ppb; 1.30 ± 1.50 ppb). Our findings suggest that although training farmers to adopt good agricultural practices was observed to be efficient in mitigating the problem of aflatoxins, the receptiveness of farmers to different aspects of the training may have differed. Therefore, in designing an optimized regional aflatoxin contamination strategy, local applicability should be considered.

Effective Altruism as an Ethical Lens on Research Priorities

Effective altruism is an ethical framework for identifying the greatest potential benefits from investments. Here, we apply effective altruism concepts to maximize research benefits through identification of priority stakeholders, pathosystems, and research questions and technologies. Priority stakeholders for research benefits may include smallholder farmers who have not yet attained the minimal standards set out by the United Nations Sustainable Development Goals; these farmers would often have the most to gain from better crop disease management, if their management problems are tractable. In wildlands, prioritization has been based on the risk of extirpating keystone species, protecting ecosystem services, and preserving wild resources of importance to vulnerable people. Pathosystems may be prioritized based on yield and quality loss, and also factors such as whether other researchers would be unlikely to replace the research efforts if efforts were withdrawn, such as in the case of orphan crops and orphan pathosystems. Research products that help build sustainable and resilient systems can be particularly beneficial. The "value of information" from research can be evaluated in epidemic networks and landscapes, to identify priority locations for both benefits to individuals and to constrain regional epidemics. As decision-making becomes more consolidated and more networked in digital agricultural systems, the range of ethical considerations expands. Low-likelihood but high-damage scenarios such as generalist doomsday pathogens may be research priorities because of the extreme potential cost. Regional microbiomes constitute a commons, and avoiding the "tragedy of the microbiome commons" may depend on shifting research products from "common pool goods" to "public goods" or other categories. We provide suggestions for how individual researchers and funders may make altruism-driven research more effective.[Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

International Plant Pathology: Past and Future Contributions to Global Food Security

The challenge of feeding the current and future world population is widely recognized, and the management of plant diseases has an important role in overcoming this. This paper explores the ways in which international plant pathology has contributed and continues to support efforts to secure adequate, safe and culturally appropriate nourishment and livelihoods for present and future generations. For the purposes of this paper, "international plant pathology" refers to the work that plant pathologists do when they work across international borders, with a focus on enhancing food security in tropical regions. Significant efforts involve public and philanthropic resources from the global North for addressing plant disease concerns in the global South, where food security is a legitimate and pressing concern. International disease management efforts are also aimed at protecting domestic food security, for example when pathogens of major staples migrate across national borders. In addition, some important crops are largely produced in tropical countries and consumed globally, including in industrialized countries; the diseases of these crops are of international interest, and they are largely managed by the private sector. Finally, host-microbe interactions are fascinating biological systems, and basic research on plant diseases of international relevance has often yielded insights and technologies with both scientific and practical implications.

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.

Aflatoxin Exposure from Milk in Rural Kenya and the Contribution to the Risk of Liver Cancer

Milk is an important commodity in Kenya; the country has the largest dairy herd and highest per capita milk consumption in East Africa. As such, hazards in milk are of concern. Aflatoxin M₁ (AFM₁) is a toxic metabolite of aflatoxin B₁ (AFB₁) excreted in milk by lactating animals after ingesting AFB₁-contaminated feeds. This metabolite is injurious to human health, but there is little information on the risk to human health posed by AFM₁ in milk in rural Kenya. To fill this gap, a quantitative risk assessment (QRA) applying probabilistic statistical tools to quantify risks was conducted. This assessed the risk of liver cancer posed by AFM₁ in milk, assuming 10-fold lower carcinogenicity than AFB₁. Data from four agro–ecological zones in Kenya (semi-arid, temperate, sub-humid and humid) were used. We estimated that people were exposed to between 0.3 and 1 ng AFM₁ per kg body weight per day through the consumption of milk. The annual incidence rates of cancer attributed to the consumption of AFM₁ in milk were 3.5 × 10⁻³ (95% CI: 3 × 10⁻³–3.9 × 10⁻³), 2.9 × 10⁻³ (95% CI: 2.5 × 10⁻³–3.3 × 10⁻³), 1.4 × 10⁻³ (95% CI: 1.2 × 10⁻³–1.5 × 10⁻³) and 2.7 × 10⁻³ (95% CI: 2.3 × 10⁻³–3 × 10⁻³) cancers per 100,000 in adult females, adult males, children 6–18 years old, and in children less than five years old, respectively. Our results show that aflatoxin exposure from milk contributes relatively little to the incidence of liver cancer. Nonetheless, risk managers should take action based on cumulative exposure from all sources of aflatoxins.

Genetic Profiling of Aspergillus Isolates with Varying Aflatoxin Production Potential from Different Maize-Growing Regions of Kenya

Highly toxigenic strains of Aspergillus flavus have been reported to frequently contaminate maize, causing fatal aflatoxin poisoning in Kenya. To gain insights into the environmental and genetic factors that influence toxigenicity, fungi (n = 218) that were culturally identified as A. flavus were isolated from maize grains samples (n = 120) from three regions of Kenya. The fungi were further characterized to confirm their identities using a PCR-sequence analysis of the internal transcribed spacer (ITS) region of rDNA which also revealed all of them to be A. flavus. A subset of 72 isolates representing ITS sequence-based phylogeny cluster and the agroecological origin of maize samples was constituted for subsequent analysis. The analysis of partial calmodulin gene sequences showed that the subset consisted of A. flavus (87%) and Aspergillus minisclerotigenes (13%). No obvious association was detected between the presence of seven aflatoxin biosynthesis genes and fungal species or region. However, the presence of the aflD and aflS genes showed some association with aflatoxin production. The assessment of toxigenicity showed higher aflatoxin production potential in A. minisclerotigenes isolates. Given that A. minisclerotigenes were mainly observed in maize samples from Eastern Kenya, a known aflatoxin hotspot, we speculate that production of copious aflatoxin is an adaptative trait of this recently discovered species in the region.

Development of an IgY-based lateral flow immunoassay for detection of fumonisin B in maize

Fumonisin is one of the most prevalent mycotoxins in maize, causing substantial economic losses and potential health risks in human and animals. In the present study, in-house polyclonal IgY antibody against fumonisin group B (FB) was applied for the development of a competitive lateral flow immunoassay detecting these mycotoxins in maize grains with the limit of detection of 4000 µg/kg, which corresponds to the maximum residue limit adopted by The International Codex Alimentarius Commission. To this end, factors affecting the test performance including nitrocellulose membrane type, dilution factor of maize homogenates in running buffer, amount of detection conjugate, and incubation time between detection conjugate and samples were optimized. Under the optimal condition (UniSart ^®CN140 nitrocellulose membrane, FB ₁-BSA immobilized at 1 µg/cm, 1:10 dilution factor, 436 ng of gold nanoparticle conjugate, 30 minutes of incubation), the developed test could detect both FB ₁ and FB ₂ in maize with limit of detection of 4000 µg/kg, and showed no cross-reactivity to deoxynivalenol, ochratoxin A, aflatoxin B1 and zearalenone. When applied to detect FB ₁ and FB ₂ in naturally contaminated maize samples, results obtained from the developed assay were in good agreement with those from the high-performance liquid chromatography method. This lateral flow immunoassay is particularly suitable for screening of fumonisins in maize because of its simplicity and cost-effectiveness.

Development of an IgY-based lateral flow immunoassay for detection of fumonisin B in maize

Fumonisin is one of the most prevalent mycotoxins in maize, causing substantial economic losses and potential health risks in human and animals. In the present study, in-house polyclonal IgY antibody against fumonisin group B (FB) was applied for the development of a competitive lateral flow immunoassay detecting these mycotoxins in maize grains with the limit of detection of 4000 µg/kg, which corresponds to the maximum residue limit adopted by The International Codex Alimentarius Commission. To this end, factors affecting the test performance including nitrocellulose membrane type, dilution factor of maize homogenates in running buffer, amount of detection conjugate, and incubation time between detection conjugate and samples were optimized. Under the optimal condition (UniSart ®CN140 nitrocellulose membrane, FB 1-BSA immobilized at 1 µg/cm, 1:10 dilution factor, 436 ng of gold nanoparticle conjugate, 30 minutes of incubation), the developed test could detect both FB 1 and FB 2 in maize with limit of detection of 4000 µg/kg, and showed no cross-reactivity to deoxynivalenol, ochratoxin A, aflatoxin B1 and zearalenone. When applied to detect FB 1 and FB 2 in naturally contaminated maize samples, results obtained from the developed assay were in good agreement with those from the high-performance liquid chromatography method. This lateral flow immunoassay is particularly suitable for screening of fumonisins in maize because of its simplicity and cost-effectiveness.

Influence of socio-economic and agronomic factors on aflatoxin and fumonisin contamination of maize in western Kenya

Consumption of maize contaminated with mycotoxins has been associated with detrimental health effects. A farm survey covering 116 push-pull and 139 non-push-pull cropping systems was conducted to determine the socio-economic and agronomic factors that influence farmers' knowledge on incidence and contamination of maize by ear rots and associated mycotoxins in western Kenya. All the respondents were smallholder farmers between the ages of 23 and 80 years, with 50% of them being female. Maize samples were collected from the standing crop in the field of each interviewed farmer and analyzed for aflatoxin and fumonisin. Only a small proportion of farmers had knowledge of aflatoxin and ear rots in maize. Overall, less than 20% of maize samples were contaminated with both aflatoxin and fumonisin, and more maize samples were contaminated with fumonisin as compared to aflatoxin. Proportions of maize samples containing higher than the acceptable Kenyan regulatory threshold (10 µg/kg) for aflatoxin and European Commission regulatory threshold (1,000) µg/kg for fumonisin were lower in maize samples from push-pull cropping system. Age of farmer and county of residence were significantly and positively associated with knowledge of aflatoxin, while cropping system, county of residence, and level of education were positively associated with knowledge of maize ear rots. There was strong correlation between knowledge of maize ear rots and knowledge of aflatoxin. Levels of both aflatoxin and fumonisin were significantly and positively associated with the use of diammonium phosphate (DAP) fertilizer at planting. Aflatoxin levels were also positively associated with stemborer damage. Agronomic practices were not significantly different between push-pull and non-push-pull farmers. However, use of DAP fertilizer was the most important agronomic factor since it was associated with both aflatoxin and fumonisin contamination of maize. These results imply that creating awareness is key to mitigation of ear rots and mycotoxin contamination of maize. The results also suggest that the levels of aflatoxin and fumonisin in maize in western Kenya were influenced both by pre-harvest agronomic practices and by the cropping system adopted, push-pull or not.

Effects of the Use of Good Agricultural Practices on Aflatoxin Levels in Maize Grown in Nandi County, Kenya

Aflatoxin contaminated maize is of public health concern in Kenya. Training farmers on good agricultural practice (GAP) has been touted as a mitigative measure. Little is known of the effect of such training on aflatoxin levels in maize grown in Kenya. This study evaluated what effect training farmers on GAP has on aflatoxin levels in maize grown in Kaptumo, Kilibwoni, and Kipkaren divisions in Nandi County, Kenya. Ninety farmers were recruited into farmer field schools and a questionnaire on GAP administered to each farmer. Maize samples were collected from the farmers and analyzed for aflatoxins using competitive enzyme-linked immunosorbent assay (c-ELISA). All farmers weeded their farms before planting, prepared the land, correctly spaced the seedlings, sorted the maize after shelling, cleaned stores before use and knew that aflatoxins were harmful to humans and animals. Eighty-one farmers did early planting, 88/90 did stooking after harvesting, 89/90 applied fertilizer, 89/90 cleared bushes around the stores, 87/90 used wooden pallets to store maize, 89/90 dried maize after harvesting, 83/90 did crop rotation, and 89/90 used clean transport. Moreover, 62/90 had a relative who had died from liver cancer, 13/90 had fed damaged/rotten seeds to animals, and 45/90 had stored harvested seeds on the ground. The mean aflatoxin levels in season 1 were significantly different from season 2 (1.918 ± 1.065; 1.301 ± 1.501). Our findings suggest that some aspects of the training on GAP were better received than others. Training farmers on GAP results in a decrease in aflatoxin levels in maize grown in Nandi County. Farmers in other maize growing areas of Kenya may benefit from similar training on GAP.

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.

Occurrence and Levels of Aflatoxins in Fish Feeds and Their Potential Effects on Fish in Nyeri, Kenya

Aflatoxins are fungal metabolites that contaminate foods and feeds, causing adverse health effects in humans and animals. This study determined the occurrence of aflatoxins in fish feeds and their potential effects on fish. Eighty-one fish feeds were sampled from 70 farms and 8 feed manufacturing plants in Nyeri, Kenya for aflatoxin analysis using competitive enzyme-linked immunosorbent assay. Fish were sampled from 12 farms for gross and microscopic pathological examination. Eighty-four percent of feeds sampled tested positive for aflatoxins, ranging from 1.8 to 39.7 µg/kg with a mean of 7.0 ± 8.3 µg/kg and the median of 3.6 µg/kg. Fifteen feeds (18.5%) had aflatoxins above the maximum allowable level in Kenya of 10 µg/kg. Homemade and tilapia feeds had significantly higher aflatoxin levels than commercial and trout feeds. Feeds containing maize bran and fish meal had significantly higher aflatoxin levels than those without these ingredients. Five trout farms (41.7%) had fish with swollen abdomens, and enlarged livers with white or yellow nodules, which microscopically had large dark basophilic hepatic cells with hyperchromatic nuclei in irregular cords. In conclusion, aflatoxin contamination of fish feeds is prevalent in Nyeri, and may be the cause of adverse health effects in fish in this region.

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.

Factors associated with the high prevalence of oesophageal cancer in Western Kenya: a review

Oesophageal carcinoma (OC) is highly prevalent in Western Kenya especially among the members of the Kalenjin community who reside in the Northern and Southern areas of the Rift Valley. Previous authors have suggested potential association of environmental and genetic risk factors with this high prevalence. The environmental factors that have been suggested include contamination of food by mycotoxins and/or pesticides, consumption of traditional alcohol (locally referred to “Busaa” and “Chan’gaa”), use of fermented milk (“Mursik”), poor diet, tobacco use and genetic predisposition. The aim of this paper is to critically examine the potential contribution of each of the factors that have been postulated to be associated with the high prevalence of the disease in order to establish the most likely cause. We have done this by analyzing the trends, characteristics and behaviours that are specifically unique in the region, and corroborated this with the available literature.

From our findings, the most plausible cause of the high incidence of OC among the Kalenjin community is mycotoxins, particularly fumonisins from the food chain resulting from poor handling of cereals; particularly maize combined with traditional alcohol laced with the toxins interacting synergistically with other high-risk factors such as dietary deficiencies associated alcoholism and viral infections, especially HPV. Urgent mitigating strategies should be developed in order to minimize the levels of mycotoxins in the food chain.

Review: Food loss and waste in Sub-Saharan Africa

The research, development practitioner, and donor community has begun to focus on food loss and waste - often referred to as post-harvest losses (PHL) - in Sub-Saharan Africa. This article reviews the current state of the literature on PHL mitigation. First, we identify explicitly the varied objectives underlying efforts to reduce PHL levels. Second, we summarize the estimated magnitudes of losses, evaluate the methodologies used to generate those estimates, and explore the dearth of thoughtful assessment around "optimal" PHL levels. Third, we synthesize and critique the impact evaluation literature around on-farm and off-farm interventions expected to deliver PHL reduction. Fourth, we suggest a suite of other approaches to advancing these same objectives, some of which may prove more cost-effective. Finally, we conclude with a summary of main points.

Implications of patient-borne costs associated with pediatric neurosurgical care in eastern Africa

OBJECTIVE Pediatric neurosurgery can be highly cost-effective even in the developing world, but delivery of these services is hampered by resource limitations at the levels of both health care infrastructure and individual patients. Few studies have evaluated costs borne by neurosurgical patients in the developing world and their potential implications for efficient and effective delivery of care in this population. METHODS The families of 40 pediatric neurosurgery patients were surveyed in February 2015 at the AIC Kijabe Hospital in Kijabe, Kenya. Costs associated with obtaining inpatient care were assessed. RESULTS Patient families were charged an average of US $539.44 for neurosurgical services, representing 132% of their annual income. Indirect expenses (transport, food and lodging, lost wages) constituted US $79.37, representing 14.7% of the overall cost and 19.5% of their annual income. CONCLUSIONS Expansion of pediatric neurosurgical services throughout the developing world necessitates increased attention to seemingly insignificant expenses that are absorbed by patients and their families. Even when all direct costs are covered at the institutional or national level, without additional assistance, some patients may be too poor to obtain even "free" neurosurgical care.