Distribution of mycotoxins and risk assessment of maize consumers in five agro-ecological zones of Nigeria

Disease Burden Estimation of Hepatocellular Carcinoma Attributable to Dietary Aflatoxin Exposure in Sichuan Province, China

BACKGROUND

Aflatoxin B1 (AFB1), AFB2, AFG1, and AFG2 are Group 1 human carcinogens, with AFB1 notably increasing hepatocellular carcinoma (HCC) risk. Sichuan Province, China, with its subtropical monsoon climate, is susceptible to AF contamination in various food items. However, the HCC disease burden attributable to lifetime chronic dietary AF intake in Sichuan has not been investigated.

METHODS

The contamination data of AFB1, AFB2, AFG1, AFG2, and AFM1 across 20 food categories were analyzed from 2012 to 2023 in Sichuan. Along with the consumption data gathered from the 2011 China National Nutrition and Health Survey, the FDA-iRISK simulated the lifetime chronic dietary exposure patterns of ∑5AF and estimated the associated HCC burden using disability-adjusted life year (DALY) as the metric.

RESULTS

As for the mean AF contamination level in food from Sichuan, the estimated lifetime average daily dose (LADD) of ∑5AF intake was 9.77 ng/kg bw/day at minimum and 26.0 ng/kg bw/day at maximum, resulting in the lifetime HCC risks per person of 0.106% and 0.283%. The corresponding HCC burdens were 16.87 DALY/100,000 people/year and 44.95 DALY/100,000 people/year, respectively. In the same scenario, the LADD and the risk of HCC in males were higher than in females, but the PAF was higher in females. However, the high (P95) AF contamination level in food caused 2-3 times higher LADD and HCC burden than the mean level of AF occurrence. Among the studied food categories, grains and their products were the primary dietary sources of dietary AF exposure.

CONCLUSIONS

Sichuan population's lifetime exposure to ∑5AF results in an HCC burden higher than the global level. It is recommended to continuously monitor and control AF contamination in Sichuan, particularly those highly vulnerable food categories, and the HCC disease burden should remain a concern in future research efforts.

Disease burden contributed by dietary exposure to aflatoxins in a mountainous city in Southwest China

Introduction

Aflatoxins (AFT) identified as a Group 1 human carcinogen naturally contaminate various types of food and could increase the risk of hepatocellular carcinoma (HCC) through dietary intake. Chongqing municipality is located in Southwest China with subtropical monsoon climate which is conducive to AFT contamination in crops. However, the burden of HCC caused by the dietary exposure of the population in Chongqing to AFT has not been quantified.

Methods

The burden of HCC was estimated in terms of Disability Adjusted Life Year (DALY) using FDA-iRISK software. Dietary exposure to AFT in three food categories including grain and its products, nuts and seeds, and spices was assessed.

Results

The lifetime average daily dose (LADD) of AFT exposure for the population ranged from 2.40 to 8.25 ng/kg bw/day and 9.51 to 15.10 ng/kg bw/day at the mean and heavy (P95) AFT contamination levels, respectively. Among the three food categories, grain and its products contributed most to AFT exposure of the population. The estimated DALYs related to HCC induced by AFT were 162,000-556,000 and 641,000-1,020,000; the DALY rates were 6.47-22.20 and 25.59-40.72 per 100,000 persons per year; and the population attribution fractions (PAF) were 1.68-5.78% and 6.66-10.60%.

Discussion

Although the burden of HCC caused by dietary AFT was estimated to be relatively low among the population, the overall health burden might be underestimated owing to the uncertainties of this dataset. Thus, the overall health burden associated with AFT intake should still be of concern in further studies.

Ultra-fast RP-HPLC-FD-DAD for quantification of total aflatoxins in maize, rice, wheat, peanut and poultry feed without sample clean up, and population exposure risk assessment in Katsina, Nigeria: an optimization study

This study reports the development and validation of a simple, yet efficient method called the ultra-fast reverse phase high-performance liquid chromatography with fluorescence and photodiode array detector (UF-RP-HPLC-FD-DAD) to extract and quantify the total aflatoxin from grains and poultry feed. The proposed method is used to determine the total aflatoxin content in 150 samples of maize, rice, wheat, peanut and poultry feed obtained from open markets in a state in Nigeria. The extent of consumer exposure to aflatoxins and the risk of developing hepatocellular carcinoma (HCC) are evaluated. The UF-RP-HPLC-FD-DAD method was found to be satisfactorily accurate, sensitive and reliable as ascertained by its excellent validation outcomes (R² > 0.999, LoD < 0.08 ng g^-1, LoQ < 0.2 ng g^-1, recovery = 90-102%). The aflatoxin levels in food grains and poultry feed samples obtained in this study implied a moderate dietary exposure of between 10.67 and 20.77 ng/kg BW/day, in which the risk of developing HCC was estimated to be between 6.27 and 21.40% per 100,000 adults/year. Hence, greater monitoring of marketed food and feed is required, besides the deployment of strict controls and preventive techniques to minimize the population's exposure to a high dietary level of aflatoxins.

A Comprehensive Review on Bio-Preservation of Bread: An Approach to Adopt Wholesome Strategies

Bread is a food that is commonly recognized as a very convenient type of food, but it is also easily prone to microbial attack. As a result of bread spoilage, a significant economic loss occurs to both consumers and producers. For years, the bakery industry has sought to identify treatments that make bread safe and with an extended shelf-life to address this economic and safety concern, including replacing harmful chemical preservatives. New frontiers, on the other hand, have recently been explored. Alternative methods of bread preservation, such as microbial fermentation, utilization of plant and animal derivatives, nanofibers, and other innovative technologies, have yielded promising results. This review summarizes numerous research findings regarding the bio-preservation of bread and suggests potential applications of these techniques. Among these techniques, microbial fermentation using lactic acid bacteria strains and yeast has drawn significant interest nowadays because of their outstanding antifungal activity and shelf-life extending capacity. For example, bread slices with Lactobacillus plantarum LB1 and Lactobacillus rossiae LB5 inhibited fungal development for up to 21 days with the lowest contamination score. Moreover, various essential oils and plant extracts, such as lemongrass oil and garlic extracts, demonstrated promising results in reducing fungal growth on bread and other bakery products. In addition, different emerging bio-preservation strategies such as the utilization of whey, nanofibers, active packaging, and modified atmospheric packaging have gained considerable interest in recent days.

Fungal Diversity and Aflatoxins in Maize and Rice Grains and Cassava-Based Flour (Pupuru) from Ondo State, Nigeria

Grains and cassava-based foods serve as major dietary sources for many households in Nigeria. However, these foods are highly prone to contamination by moulds and aflatoxins owing to poor storage and vending practices. Therefore, we studied the fungal diversity in maize, cassava-based flour (pupuru), and rice vended in markets from Ondo state, Nigeria, and assessed their aflatoxin levels using an enzyme-linked immunosorbent assay. Molecular analysis of 65 representative fungal isolates recovered from the ground grains and pupuru samples revealed 26 species belonging to five genera: Aspergillus (80.9%), Penicillium (15.4%), and Talaromyces (1.9%) in the Ascomycota; Syncephalastrum (1.2%) and Lichtheimia (0.6%) in Mucoromycota. Aspergillus flavus was the predominant species in the ground grains and pupuru samples. Aflatoxins were found in 73.8% of the 42 representative food samples and 41.9% exceeded the 10 μg/kg threshold adopted in Nigeria for total aflatoxins.

Prevalence of Aflatoxin- and Fumonisin-Producing Fungi Associated with Cereal Crops Grown in Zimbabwe and Their Associated Risks in a Climate Change Scenario

In most sub-Saharan African countries, staple cereal grains harbor many fungi and some produce mycotoxins that negatively impact health and trade. Maize and three small grain cereals (sorghum, pearl millet, and finger millet) produced by smallholder farmers in Zimbabwe during 2016 and 2017 were examined for fungal community structure, and total aflatoxin (AF) and fumonisin (FM) content. A total of 800 maize and 180 small grain samples were collected at harvest and during storage from four agroecological zones. Fusarium spp. dominated the fungi associated with maize. Across crops, Aspergillusflavus constituted the main Aspergillus spp. Small grain cereals were less susceptible to both AF and FM. AF (52%) and FM (89%) prevalence was higher in maize than in small grains (13-25% for AF and 0-32% for FM). Less than 2% of small grain samples exceeded the EU regulatory limit for AF (4 µg/kg), while <10% exceeded the EU regulatory limit for FM (1000 µg/kg). For maize, 28% and 54% of samples exceeded AF and FM Codex guidance limits, respectively. Higher AF contamination occurred in the drier and hotter areas while more FM occurred in the wetter year. AF exposure risk assessment revealed that small grain consumption posed low health risks (≤0.02 liver cancer cases/100,000 persons/year) while maize consumption potentially caused higher liver cancer rates of up to 9.2 cases/100,000 persons/year depending on the locality. Additionally, FM hazard quotients from maize consumption among children and adults were high in both years, but more so in a wet year than a dry year. Adoption of AF and FM management practices throughout the maize value chain coupled with policies supporting dietary diversification are needed to protect maize consumers in Zimbabwe from AF- and FM-associated health effects. The higher risk of health burden from diseases associated with elevated concentration of mycotoxins in preferred maize during climate change events can be relieved by increased consumption of small grains.

Thinking Out of the Box: On the Ability of Zea mays L. to Biotrasform Aflatoxin B1 Into Its Modified Forms

While aflatoxin metabolism in animals has been clarified, very limited information is so far available on the possible biotransformation occurring in plants. Therefore, this work aimed at investigating whether AFB1 metabolites could occur in field-grown infected maize and the putative role of Zea mays L. metabolism in their production. For such scope, asymptomatic in vitro-grown plantlets and in silico evaluations of plant transforming enzymes were used to pinpoint how plants may handle these compounds. Our data demonstrated the role of maize plants in the production of Phase I hydroxylated aflatoxins, including, among others, AFM1, AFM2, and aflatoxicol, and suggest that plant cytochromes may be involved in this biotransformation of AFB1.

Thermogravimetric Analysis of Modified Montmorillonite Clay for Mycotoxin Decontamination in Cereal Grains

Thermogravimetric analysis (TGA) was carried out to study the stability of nanoformulations used for the decontamination of mycotoxins. The TGA patterns of the nanoformulations from montmorillonite clay and Cymbopogon citratus (lemongrass) extracts were assessed with temperature ranging from ambient (20°C) to 1000°C. The various nanoformulations studied included unmodified montmorillonite clay (Mont), montmorillonite washed with sodium chloride (Mont-Na), montmorillonite mixed with lemongrass essential oil (Mont-LGEO), and montmorillonite mixed with an equal quantity of lemongrass powder (Mont-LGP). There was no significant difference in the median of the various nanoformulations within 4 weeks at p < 0.05 using the Kruskal-Wallis nonparametric test. For the TGA, the first degradation for montmorillonite clay and the nanoformulations occurred at a temperature between 80 and 101°C and was attributed to the loss of lattice water outside the coordination sphere with a range of 3.5-6.5% weight loss. The second degradation occurred within the temperature of 338 to 344°C, and the third, at a temperature between 640 and 668°C for Mont and the formulations of Mont-Na, Mont-LGEO, and Mont-LGP. There were strong similarities in the degradation patterns of Mont and Mont-Na with the minimum difference being the relatively higher weight loss of the sodium-exchanged cation for Mont-Na at the third degradation step. Hence, the order of stability from the most resistant to the least resistant to degradation is as follows: Mont-LGEO ≥ Mont-Na ≥ Mont ≥ Mont-LGP.

Phylogenetic diversity and prevalence of mycoflora in ready-to-eat supermarket and roadside-vended peanuts

Little is known of the mycobiota present in ready-to-eat peanuts consumed in Southern Africa. Knowledge of the mycobiota and aflatoxigenic species can elucidate potential health risks associated with consumption of ready-to-eat peanuts sold by supermarkets and roadside vendors. We investigated the culturable mycobiota diversity in supermarket and roadside-vended peanuts as well as the presence of five aflatoxin biosynthesis pathway-related genes (aflR, aflJ, aflM, aflD, and aflP) in 15 suspected aflatoxigenic isolates, with a focus on Mafikeng, South Africa. Mean colony-forming unit (CFU) counts of 288.7 and 619.7 CFU/g were observed in supermarket and roadside-vended peanuts, respectively. A total of 145 fungal isolates comprising 26 distinct taxa (based on 97% internal transcribed spacer region [ITS1-5.8S-ITS2] sequence similarity) were obtained, including strains representing Aspergillus, Acremonium, Alternaria, Bipolaris, Chaetomium, Ectophoma, Epicoccum, Hamigera, Leancillium, Monascus, Penicillium, Periconia, Talaromyces, and Trichoderma. Phylogenetic analyses of concatenated sequences of the ITS1-5.8S-ITS2, β-tubulin, and calmodulin genes delineated the species of Aspergillus, which included A. flavus, A. fumigatus, A. hiratsukae, A. niger, and A. parasiticus. Higher species richness was obtained from supermarket peanuts compared with roadside-vended peanuts, with eight species common to both sources. Across supermarket or roadside-vended peanuts, A. fumigatus, A. niger, and A. flavus were prevalent (>40% incidence). In contrast, strains related to or representing Ectophoma multirostata, Aspergillus hiratsukae, Bipolaris zeae, Chaetomium bostrychodes, Epicoccum nigrum, Hamigera paravellanea, Lecanicillium aphanocladii, Monascus ruber, Periconia macrospinosa, Periconia lateralis, Talaromyces funiculosus, Talaromyces minioluteus, Talaromyces wortmannii, Talaromyces spp., and Trichoderma sp. were detected in either supermarket or roadside-vended peanuts. Among the five aflatoxin biosynthesis pathway-related genes, aflD and aflM were more prevalent (87%) and aflR was the least prevalent (40%). Findings suggest that roasted peanuts meant for human consumption and sold at supermarkets and by roadside vendors are contaminated with potential toxin-producing fungi. Hence, proper processing and packaging of peanuts before vending is recommended.

Parallel validation of a green-solvent extraction method and quantitative estimation of multi-mycotoxins in staple cereals using LC-MS/MS

In this study, 15 different mycotoxins were estimated in three staple cereals from selected agro-ecological regions in Nigeria using a 'novel' green extraction method, pressurized hot water extraction (PHWE) in comparison to a conventional solvent extraction method. Discrimination of the results of PHWE and solvent extraction using principal component analysis (PCA) and orthogonal projection to latent structures discriminate analysis (OPLS-DA) did not yield any differential clustering patterns. All maize samples (n = 16), 32% (n = 38) of sorghum and 35% (n = 37) of millet samples were positive for at least one of the 15 tested mycotoxins. Contamination levels for the cereals were higher in the warm humid rain forest region and gradually decreased towards the hot and arid region in the north of the country. The results demonstrate the applicability of PHWE as a possible alternative extraction method to conventional methods of extraction, which are solvent based.

Risk assessment of mycotoxins in stored maize: case study of Shandong, China

Risk characterisation of dietary exposure of aflatoxins (AFs), fumonisins (FBs), deoxynivalenol (DON), zearalenone (ZEA) in maize from Shandong Province was conducted in this study. A total of 520 maize samples were collected after harvesting in 2014 and 2015 from 26 selected villages in Shandong Province, China. A deterministic approach was used in the current study. The dietary intake data of maize was obtained from ‘Shandong Statistical Yearbook 2018’. The risk characterisation of FBs, DON, and ZEA was evaluated in 4 population groups (2 to 6-year-old children, standard adults, city adults and village adults) based on probable intake. 2 to 6-year-old children and adults were exposed to FBs (0.42 and 0.20 μg/kg body weight (bw)/day), DON (0.04 and 0.019 μg/kg bw/day), and ZEA (0.0024 and 0.0011 μg/kg bw/day) through mean maize consumption in diets, which was lower than the provisional maximum tolerable daily intake of each mycotoxin established by JECFA. Risk assessments showed a low risk for liver cancer due to consumption of aflatoxin B1 (0.027-0.21 cases per 100,000 persons per year) contaminated maize compared with China’s current liver cancer incidence of 24.6 cases per 100,000 persons per year.

Willingness to pay of Nigerian poultry producers and feed millers for aflatoxin‐safe maize

Dietary aflatoxin exposure is a widespread problem in the developing world and causes severe negative health consequences to humans and livestock animals. A new biological control product, called Aflasafe, has been introduced in Nigeria to mitigate aflatoxin contamination of maize in the field and in storage. No known prior work has estimated how much African agribusinesses using maize for animal feed will pay for aflatoxin‐safe maize. This study measured the levels of Aflasafe awareness, surveyed current aflatoxin management practices, and estimated, using choice experiments, willingness to pay (WTP) for aflatoxin‐safe maize by Nigerian poultry producers and feed millers. Data was gathered from 272 orally administered surveys, which included discrete choice experiments examining maize purchasing decisions. Results suggest that the proportion of enterprises that were aware of aflatoxin was found to vary across states. Two latent classes of Nigerian poultry producers and feed millers were identified that were willing to pay average premiums of 4.9% and 30.9%, respectively for maize with 10 parts per billion (ppb) aflatoxin concentration relative to maize with 20 ppb aflatoxin concentration. Both latent classes were, on average, willing to pay larger premiums for maize with 4 ppb aflatoxin concentration. There was evidence that latent class membership, and hence WTP, varied based on awareness of aflatoxin and across geographies.

Mycotoxins in uncooked and plate-ready household food from rural northern Nigeria

In order to understand the changes in toxic metabolite profiles in uncooked and cooked foods, samples of flour/grain (n = 40) and their corresponding plate-ready food (n = 39) were collected from 40 households in two states of northern Nigeria. The food samples were analyzed for multiple fungal metabolites by LC-MS/MS and daily intakes of mycotoxins in the diets were estimated and compared to established margin of exposure (MOE) and tolerable daily intake (TDI) values. Both food groups contained 65 fungal and plant metabolites, inclusive of 23 mycotoxins. The mean concentrations of aflatoxin B₁, beauvericin, fumonisin B₁ (FB₁), FB₂, FB₃, hydrolysed FB₁, moniliformin and nivalenol were significantly (p < 0.05) higher in flour than in the plate-ready food samples. The levels of several mycotoxins were higher in the flour samples than in plate-ready meals by 129-383%. The dilution effect from proportionate mixing of flour samples with water led to 48-100% reduction in detectable mycotoxins in flour to plate-ready meals. Aflatoxins and fumonisins co-occurred in 36% of the plate-ready foods. Exposures of households to aflatoxins and fumonisins based on 95% CI concentration of mycotoxins in the meals were high, suggesting potential health risks based on calculated low MOE and exceedence of stipulated TDI value, respectively.

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.

Assessing the combined toxicity of the natural toxins, aflatoxin B1, fumonisin B1 and microcystin-LR by high content analysis

As human co-exposure to natural toxins through food and water is inevitable, risk assessments to safeguard health are necessary. Aflatoxin B₁ and fumonisin B₁, frequent co-contaminants of maize and microcystin-LR, produced in freshwater by cyanobacteria are all naturally occurring potent toxins that threaten human health. Populations in the poorest regions of the world may suffer repeated simultaneous exposure to these contaminants. Using High Content Analysis, multiple cytotoxicity endpoints were measured for the individual toxins and mixtures in various cell lines. Results highlighted that significant cytotoxic effects were observed for aflatoxin B₁ in all cell lines while no cytotoxic effects were observed for fumonisin B1 or microcystin-LR. Aflatoxin B₁/microcystin-LR was cytotoxic in the order HepG2 > Caco-2 > MDBK. Fumonisin B₁/microcystin-LR affected MDBK cells. The ternary mixture was cytotoxic to all cell lines. Most combinations were additive, however antagonism was observed for binary and ternary mixtures in HepG2 and MDBK cell lines at low and high concentrations. Synergy was observed in all cell lines, including at low concentrations. The combination of these natural toxins may pose a significant risk to populations in less developed countries. Furthermore, the study highlights the complexity around trying to regulate for human exposure to multiple contaminants.

Mold spoilage of bread and its biopreservation: A review of current strategies for bread shelf life extension

Microbial spoilage of bread and the consequent waste problem causes large economic losses for both the bakery industry and the consumer. Furthermore the presence of mycotoxins due to fungal contamination in cereals and cereal products remains a significant issue. The use of conventional chemical preservatives has several drawbacks, necessitating the development of clean-label alternatives. In this review, we describe current research aiming to extend the shelf life of bread through the use of more consumer friendly and ecologically sustainable preservation techniques as alternatives to chemical additives. Studies on the in situ-production/-expression of antifungal compounds are presented, with special attention given to recent developments over the past decade. Sourdough fermented with antifungal strains of lactic acid bacteria (LAB) is an area of increasing focus and serves as a high-potential biological ingredient to produce gluten-containing and gluten-free breads with improved nutritional value, quality and safety due to shelf-life extension, and is in-line with consumer's demands for more products containing less additives. Other alternative biopreservation techniques include the utilization of antifungal peptides, ethanol and plant extracts. These can be added to bread formulations or incorporated in antimicrobial films for active packaging (AP) of bread. This review outlines recent progress that has been made in the area of bread biopreservation and future perspectives in this important area.

Fungal isolates and metabolites in locally processed rice from five agro-ecological zones of Nigeria

This study reports the distribution of fungal isolates and fungal metabolites that naturally contaminate locally processed rice from five agro-ecological zones of Nigeria. The fungal species were isolated by the dilution plate technique and identified by appropriate diagnostics, while metabolites were determined by a liquid chromatographic tandem mass spectrometric method. Aspergillus and Penicillium species were the predominant isolates found in the rice samples while Fusarium spp. were not isolated. The mean fungal count differed significantly (p < 0.05) across the zones and ranged from 9.98 × 10² cfu g^-1 in the Southern Guinea Savannah to 96.97 × 10² cfu g^-1 in the Derived Savannah. For 16 fungal metabolites, selected from 63 positively identified fungal metabolites based on their concentration and spread across the zones, an occurrence map was constructed. The Northern Guinea Savannah recorded the highest contamination of fungal metabolites while the Sudan Savannah zone recorded the least.

Mould and mycotoxin exposure assessment of melon and bush mango seeds, two common soup thickeners consumed in Nigeria

An examination of the mould and fungal metabolite pattern in melon and bush mango seeds locally produced in Nigeria was undertaken in order to understand the mycotoxicological risk posed to consumers of both of these important and commonly consumed soup thickeners. The variation in mycotoxin levels in graded categories of both foodstuffs were also determined. Aspergillus, Fusarium, Penicillium, Mucorales and Trichoderma were the recovered fungi from the foodstuffs with Aspergillus species dominating (melon=97.8%; bush mango=89.9%). Among the Aspergillus species identified Aspergillus section Flavi dominated (melon: 72%; bush mango: 57%) and A. flavus, A. parasiticus, A. parvisclerotigenus and A. tamarii were the recovered species. About 56% and 73% of the A. flavus isolates from melon and bush mango seed samples, respectively were aflatoxigenic. Thirty-four and 59 metabolites including notable mycotoxins were found in the melon and bush mango seeds respectively. Mean aflatoxin levels (μg/kg) in melon (aflatoxin B₁ (AFB₁)=37.5 and total aflatoxins=142) and bush mango seeds (AFB₁=68.1 and total aflatoxins=61.7) were higher than other mycotoxins, suggesting potential higher exposure for consumer populations. Significantly (p<0.05) higher levels of mycotoxins were found in hand-peeled melon and discoloured bush mango seeds than in machine-peeled melon and non-discoloured seeds except for HT-2 and T-2 toxins which occurred conversely. All melon and bush mango seeds exceeded the 2μg/kg AFB₁ limit whereas all melon and 55% of bush mango seeds exceeded the 4μg/kg total aflatoxin EU limit adopted in Nigeria. This is the first report of (1) mycotoxin co-occurrence in bush mango seeds, (2) cyclopiazonic acid, HT-2 toxin, moniliformin, mycophenolic acid, T-2 toxin and tenuazonic acid occurrence, and (3) mycotoxin exposure assessment of both foodstuffs.

Bacterial Diversity and Mycotoxin Reduction During Maize Fermentation (Steeping) for Ogi Production

Bacterial diversity and community structure of two maize varieties (white and yellow) during fermentation/steeping for ogi production, and the influence of spontaneous fermentation on mycotoxin reduction in the gruel were studied. A total of 142 bacterial isolates obtained at 24-96 h intervals were preliminarily identified by conventional microbiological methods while 60 selected isolates were clustered into 39 OTUs consisting of 15 species, 10 genera, and 3 phyla by 16S rRNA sequence analysis. Lactic acid bacteria constituted about 63% of all isolated bacteria and the genus Pediococcus dominated (white maize = 84.8%; yellow maize = 74.4%). Pediococcus acidilactici and Lactobacillus paraplantarum were found at all steeping intervals of white and yellow maize, respectively, while P. claussenii was present only at the climax stage of steeping white maize. In both maize varieties, P. pentosaceus was found at 24-72 h. Mycotoxin concentrations (μg/kg) in the unsteeped grains were: white maize (aflatoxin B1 = 0.60; citrinin = 85.8; cyclopiazonic acid = 23.5; fumonisins (B1/B2/B3) = 68.4-483; zearalenone = 3.3) and yellow maize (aflatoxins (B1/B2/M1) = 22.7-513; citrinin = 16,800; cyclopiazonic acid = 247; fumonisins (B1/B2/B3) = 252-1,586; zearalenone = 205). Mycotoxins in both maize varieties were significantly (p < 0.05) reduced across steeping periods. This study reports for the first time: (a) the association of L. paraplantarum, P. acidilactici, and P. claussenii with ogi production from maize, (b) citrinin occurrence in Nigerian maize and ogi, and