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

Postharvest Practices, Perceptions, and Knowledge of Mycotoxins among Groundnut Farmers in the Adamawa, Centre, and North Regions of Cameroon

In many parts of the world, including Cameroon, mycotoxin contamination of groundnuts remains a major constraint affecting their use as food. Understanding the contributing factors is an essential intervention to reduce contamination and people's exposure to these harmful toxins. The aim of this research was to identify the factors associated with the knowledge, perceptions, and postharvest practices of groundnut farmers in three production basins in Cameroon. Data were collected through surveys and analyzed using descriptive methods and logistic regression models. The results show that groundnut farmers are little aware of the existence of mycotoxins (12%) and totally unaware of the existence of aflatoxins (100%). Only 7.1% of these farmers are aware of the effects of mycotoxins on consumer health. After evaluation, the large majority of farmers scored poor marks for knowledge (86%) and practice (98.7%) in the management of mould and mycotoxins in groundnuts. Knowledge of mycotoxins was positively associated with the level of education [OR = 3.42; (95%-IC: 1.00-16.00); p < 0.05] and region [OR = 4.49; (95%-IC: 1.09-20.3); p < 0.05]. Farmers' good practices were linked to their production experience [OR = 6.06, (95% CI: 0.91-18.4), p = 0.035]. The use of mouldy groundnut for feed was associated with age [OR = 3.34, (95% CI: 1.14-10.2), p = 0.03], sex [OR = 0. 43, (IC-95%: 1.14-1.05), p = 0.026], marital status [OR = 0.35, (IC-95%: 0.14-0.79), p = 0.015], and production region [OR = 0.27, (IC-95%: 0.13-0.56)]. In conclusion, groundnut farmers had insufficient knowledge of mycotoxins, no knowledge of aflatoxins, and suboptimal handling and storage practices for this commodity. This contributes to increasing the risk of exposure for the population and requires mitigation measures, including awareness campaigns on mycotoxins, specifically aflatoxins, and capacity building for farmers in terms of storage and postharvest management of foodstuffs.

The Occurrence and Health Risk Assessment of Aflatoxin M1 in Raw Cow Milk Collected from Tunisia during a Hot Lactating Season

Milk is a staple food that is essential for human nutrition because of its high nutrient content and health benefits. However, it is susceptible to being contaminated by Aflatoxin M1 (AFM1), which is a toxic metabolite of Aflatoxin B1 (AFB1) presented in cow feeds. This research investigated AFM1 in Tunisian raw cow milk samples. A total of 122 samples were collected at random from two different regions in 2022 (Beja and Mahdia). AFM1 was extracted from milk using the QuEChERS method, and contamination amounts were determined using liquid chromatography (HPLC) coupled with fluorescence detection (FD). Good recoveries were shown with intra-day and inter-day precisions of 97 and 103%, respectively, and detection and quantification levels of 0.003 and 0.01 µg/L, respectively. AFM1 was found in 97.54% of the samples, with amounts varying from values below the LOQ to 197.37 µg/L. Lower AFM1 was observed in Mahdia (mean: 39.37 µg/L), respectively. In positive samples, all AFM1 concentrations exceeded the EU maximum permitted level (0.050 µg/L) for AFM1 in milk. In Tunisia, a maximum permitted level for AFM1 in milk and milk products has not been established. The risk assessment of AFM1 was also determined. Briefly, the estimated intake amount of AFM1 by Tunisian adults through raw cow milk consumption was 0.032 µg/kg body weight/day. The Margin of Exposure (MOE) values obtained were lower than 10,000. According to the findings, controls as well as the establishment of regulations for AFM1 in milk are required in Tunisia.

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

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

Risks of aflatoxin exposure among adolescents in boarding schools in Kilimanjaro region, Tanzania

School feeding in low-income countries is dominated by cereals and legumes, which are susceptible to aflatoxin contamination but are usually not assessed for aflatoxins. A cross sectional study was conducted to assess aflatoxin exposure among adolescents through consumption of school meals in Kilimanjaro region. Food frequency questionnaires and 24 h dietary recalls were used to collect information on food consumption. At least four samples of common food used in school meals were collected. A deterministic approach was used to estimate the dietary aflatoxin exposure. High Performance Liquid chromatography (HPLC) was used to analyse presence of aflatoxin contamination. Results showed that, maize based food and beans were consumed on daily basis. The intake of maize flour and dehulled maize ranged from 17.5 to 738.2 g and 28.2 to 272 g per person per day respectively. Furthermore, consumption of beans and rice were in the range of 121.1 to 595.2 g and 15.7 to 42.2 g per person per day respectively. Total aflatoxins ranged 0.20-438.53 μg/kg (median 2.30 μg/kg). The highest contamination range (0.59-438.53 μg/kg) was in maize while the lowest (0.20-3.41 μg/kg) was found in rice. Similarly, the highest aflatoxin B1 (AFB1) concentration (35.88 μg/kg) was in dehulled maize while the lowest (0.44 μg/kg) was in rice. The highest dietary exposure to total aflatoxins and AFB1 due to consumption of maize ranged from 0.70 to 973.45 ng/kg/bodyweight (bw)/day, and from 0.05-81.06 ng/kg/bw/day, respectively. This pronounced risk of exposure to aflatoxins might have been contributed by a monotonous maize based diet in boarding schools. These findings call for institutions immediate interventions, such as the use of appropriate storage technologies, sorting, cleaning and winnowing in order to remove damaged grains, thereby reducing the risk of dietary exposure to aflatoxins. Likewise, the relevant ministries should consider food diversification and routine risk assessments of the susceptible crops throughout the value chain as a long-term intervention plan at policy level.

A review of microbes and chemical contaminants in dairy products in sub-Saharan Africa

Animal milk types in sub-Saharan Africa (SSA) are processed into varieties of products using different traditional methods and are widely consumed by households to support nutritional intake and diet. Dairy products contain several microorganisms, their metabolites, and other chemical compounds, some with health benefits and many others considered as potential health hazards. Consumption of contaminated milk products could have serious health implications for consumers. To access the safety of milk products across SSA, studies in the region investigating the occurrences of pathogens as well as chemical compounds such as heat stable toxins and veterinary drug residues in animal milk and its products were reviewed. This is done with a holistic view in light of the emerging exposome paradigm for improving food safety and consumer health in the region. Herein, we showed that several published studies in SSA applied conventional and/or less sensitive methods in detecting microbial species and chemical contaminants. This has serious implications in food safety because the correct identity of a microbial species and accurate screening for chemical contaminants is crucial for predicting the potential human health effects that undermine the benefits from consumption of these foods. Furthermore, we highlighted gaps in determining the extent of viral and parasitic contamination of milk products across SSA as well as investigating multiple classes of chemical contaminants. Consequently, robust studies should be conducted in this regard. Also, efforts such as development cooperation projects should be initiated by all stakeholders including scientists, regulatory agencies, and policy makers to improve the dairy product chain in SSA in view of safeguarding consumer health.

Aflatoxin M1 in Africa: Exposure Assessment, Regulations, and Prevention Strategies - A Review

Aflatoxins are the most harmful mycotoxins causing health problems to human and animal. Many acute aflatoxin outbreaks have been reported in Africa, especially in Kenya and Tanzania. When ingested, aflatoxin B1 is converted by hydroxylation in the liver into aflatoxin M1, which is excreted in milk of dairy females and in urine of exposed populations. This review aims to highlight the AFM1 studies carried out in African regions (North Africa, East Africa, West Africa, Central Africa, and Southern Africa), particularly AFM1 occurrence in milk and dairy products, and in human biological fluids (breast milk, serum, and urine) of the populations exposed. Strategies for AFM1 detoxification will be considered, as well as AFM1 regulations as compared to the legislation adopted worldwide and the assessment of AFM1 exposure of some African populations. Egypt, Kenya, and Nigeria have the highest number of investigations on AFM1 in the continent. Indeed, some reports showed that 100% of the samples analyzed exceeded the EU regulations (50 ng/kg), especially in Zimbabwe, Nigeria, Sudan, and Egypt. Furthermore, AFM1 levels up to 8,000, 6,999, 6,900, and 2040 ng/kg have been reported in milk from Egypt, Kenya, Sudan, and Nigeria, respectively. Data on AFM1 occurrence in human biological fluids have also shown that exposure of African populations is mainly due to milk intake and breastfeeding, with 85-100% of children being exposed to high levels. Food fermentation in Africa has been tried for AFM1 detoxification strategies. Few African countries have set regulations for AFM1 in milk and derivatives, generally similar to those of the Codex alimentarius, the US or the EU standards.

A Review of the Impact of Mycotoxins on Dairy Cattle Health: Challenges for Food Safety and Dairy Production in Sub-Saharan Africa

Mycotoxins are secondary metabolites of fungi that contaminate food and feed and have a significant negative impact on human and animal health and productivity. The tropical condition in Sub-Saharan Africa (SSA) together with poor storage of feed promotes fungal growth and subsequent mycotoxin production. Aflatoxins (AF) produced by Aspergillus species, fumonisins (FUM), zearalenone (ZEN), T-2 toxin (T-2), and deoxynivalenol (DON) produced by Fusarium species, and ochratoxin A (OTA) produced by Penicillium and Aspergillus species are well-known mycotoxins of agricultural importance. Consumption of feed contaminated with these toxins may cause mycotoxicoses in animals, characterized by a range of clinical signs depending on the toxin, and losses in the animal industry. In SSA, contamination of dairy feed with mycotoxins has been frequently reported, which poses a serious constraint to animal health and productivity, and is also a hazard to human health since some mycotoxins and their metabolites are excreted in milk, especially aflatoxin M1. This review describes the major mycotoxins, their occurrence, and impact in dairy cattle diets in SSA highlighting the problems related to animal health, productivity, and food safety and the up-to-date post-harvest mitigation strategies for the prevention and reduction of contamination of dairy feed.

Inhibitory Effect of Volatiles Emitted From Alcaligenes faecalis N1-4 on Aspergillus flavus and Aflatoxins in Storage

Controlling aflatoxigenic Aspergillus flavus and aflatoxins (AFs) in grains and food during storage is a great challenge to humans worldwide. Alcaligenes faecalis N1-4 isolated from tea rhizosphere soil can produce abundant antifungal volatiles, and greatly inhibited the growth of A. flavus in un-contacted face-to-face dual culture testing. Gas chromatography tandem mass spectrometry revealed that dimethyl disulfide (DMDS) and methyl isovalerate (MI) were two abundant compounds in the volatile profiles of N1-4. DMDS was found to have the highest relative abundance (69.90%, to the total peak area) in N1-4, which prevented the conidia germination and mycelial growth of A. flavus at 50 and 100 μL/L, respectively. The effective concentration for MI against A. flavus is 200 μL/L. Additionally, Real-time quantitative PCR analysis proved that the expression of 12 important genes in aflatoxin biosynthesis pathway was reduced by these volatiles, and eight genes were down regulated by 4.39 to 32.25-folds compared to control treatment with significant differences. And the A. flavus infection and AFs contamination in groundnut, maize, rice and soybean of high water activity were completely inhibited by volatiles from N1-4 in storage. Scanning electron microscope further proved that A. flavus conidia inoculated on peanuts surface were severely damaged by volatiles from N1-4. Furthermore, strain N1-4 showed broad and antifungal activity to other six important plant pathogens including Fusarium graminearum, F. equiseti, Alternaria alternata, Botrytis cinerea, Aspergillus niger, and Colletotrichum graminicola. Thus, A. faecalis N1-4 and volatile DMDS and MI may have potential to be used as biocontrol agents to control A. flavus and AFs during storage.

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

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