Co-occurrence of mycoflora, aflatoxins and fumonisins in maize and rice seeds from markets of different districts in Cairo, Egypt

Mycotoxin contamination in the Arab world: Highlighting the main knowledge gaps and the current legislation

Since the discovery of aflatoxins in the 1960s, knowledge in the mycotoxin research field has increased dramatically. Hundreds of review articles have been published summarizing many different aspects, including mycotoxin contamination per country or region. However, mycotoxin contamination in the Arab world, which includes 22 countries in Africa and Asia, has not yet been specifically reviewed. To this end, the contamination of mycotoxins in the Arab world was reviewed not only to profile the pervasiveness of the problem in this region but also to identify the main knowledge gaps imperiling the safety of food and feed in the future. To the best of our knowledge, 306 (non-)indexed publications in English, Arabic, or French were published from 1977 to 2021, focusing on the natural occurrence of mycotoxins in matrices of 14 different categories. Characteristic factors (e.g., detected mycotoxins, concentrations, and detection methods) were extracted, processed, and visualized. The main results are summarized as follows: (i) research on mycotoxin contamination has increased over the years. However, the accumulated data on their occurrences are scarce to non-existent in some countries; (ii) the state-of-the-art technologies on mycotoxin detection are not broadly implemented neither are contemporary multi-mycotoxin detection strategies, thus showing a need for capacity-building initiatives; and (iii) mycotoxin profiles differ among food and feed categories, as well as between human biofluids. Furthermore, the present work highlights contemporary legislation in the Arab countries and provides future perspectives to mitigate mycotoxins, enhance food and feed safety, and protect the consumer public. Concluding, research initiatives to boost mycotoxin research among Arab countries are strongly recommended.

Aflatoxins Contamination in Feed Commodities: From Occurrence and Toxicity to Recent Advances in Analytical Methods and Detoxification

Synthesized by the secondary metabolic pathway in Aspergilli, aflatoxins (AFs) cause economic and health issues and are culpable for serious harmful health and economic matters affecting consumers and global farmers. Consequently, the detection and quantification of AFs in foods/feeds are paramount from food safety and security angles. Nowadays, incessant attempts to develop sensitive and rapid approaches for AFs identification and quantification have been investigated, worldwide regulations have been established, and the safety of degrading enzymes and reaction products formed in the AF degradation process has been explored. Here, occurrences in feed commodities, innovative methods advanced for AFs detection, regulations, preventive strategies, biological detoxification, removal, and degradation methods were deeply reviewed and presented. This paper showed a state-of-the-art and comprehensive review of the recent progress on AF contamination in feed matrices with the intention of inspiring interests in both academia and industry.

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.

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.

Aflatoxin B1 in Rice: Effects of Storage Duration, Grain Type and Size, Production Site, and Season

ABSTRACT

Our study evaluated aflatoxin B1 (AFB1) levels in packed rice marketed in Lebanon and determined the exposure to this toxin from rice consumption. A total of 105 packed white, parboiled, and brown rice bags were collected. Enzyme-linked immunosorbent assay was used to measure AFB1. A comprehensive food frequency questionnaire was completed by 500 participants to determine patterns of rice consumption and, subsequently, the exposure levels to AFB1 from rice consumption in Lebanon. AFB1 was detected in all rice samples (100%). The average concentration ± standard deviation of AFB1 was 0.5 ± 0.3 μg/kg. Contamination ranged between 0.06 and 2.08 μg/kg. Moisture content in all rice samples was below the recommended percentage (14%). Only 1% of the samples had an AFB1 level above the European Union limit (2 μg/kg). Brown rice had a significantly higher AFB1 level than white and parboiled rice (P = 0.02), while a significant difference was found between both collections for the same brands (P = 0.016). Packing season, packing country, country of origin, presence of a food safety management certification, grain size, and time between packing and purchasing had no significant effect. Exposure to AFB1 from rice consumption in Lebanon was calculated as 0.1 to 2 ng/kg of body weight per day.

HIGHLIGHTS

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.

Efficient Adsorption of Deoxynivalenol by Porous Carbon Prepared from Soybean Dreg

A novel porous carbon adsorbent for the removal of deoxynivalenol was prepared from soybean dreg (SD). The new material was characterized by scanning electron microscopy equipped with energy dispersive X-ray spectroscopy (SEM-EDS), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) analysis, N2 adsorption/desorption measurement techniques, X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The specific surface area of the SDB-6-KOH was found to be 3655.95 m2 g-1, the pore volume was 1.936 cm3 g-1 and the average pore size was 2.125 nm. The high specific surface area and effective functional groups of the carbon material promoted the adsorption of deoxynivalenol. By comparing the adsorption effect of SDB-6-X prepared with different activators (X: KOH, K2CO3, KHCO3), SDB-6-KOH had the highest adsorption capacity. The maximum adsorption capacity of SDB-6-KOH to deoxynivalenol was 52.9877 µg mg-1, and the removal efficiency reached 88.31% at 318 K. The adsorption kinetic and isotherm data were suitable for pseudo-second-order and Langmuir equations, and the results of this study show that the novel carbon material has excellent adsorptive ability and, thus, offers effective practical application potential for the removal of deoxynivalenol.

A Review of the Methodology of Analyzing Aflatoxin and Fumonisin in Single Corn Kernels and the Potential Impacts of These Methods on Food Security

Current detection methods for contamination of aflatoxin and fumonisin used in the corn industry are based on bulk level. However, literature demonstrates that contamination of these mycotoxins is highly skewed and bulk samples do not always represent accurately the overall contamination in a batch of corn. Single kernel analysis can provide an insightful level of analysis of the contamination of aflatoxin and fumonisin, as well as suggest a possible remediation to the skewness present in bulk detection. Current literature describes analytical methods capable of detecting aflatoxin and fumonisin at a single kernel level, such as liquid chromatography, fluorescence imaging, and reflectance imaging. These methods could provide tools to classify mycotoxin contaminated kernels and study potential co-occurrence of aflatoxin and fumonisin. Analysis at a single kernel level could provide a solution to the skewness present in mycotoxin contamination detection and offer improved remediation methods through sorting that could impact food security and management of food waste.

Mycotoxin exposure is associated with increased risk of esophageal squamous cell carcinoma in Huaian area, China

BACKGROUND

Consumption of moldy food has previously been identified as a risk factor for esophageal squamous cell carcinoma (ESCC) in high-risk countries; however, what contributing roles these dietary carcinogenic mycotoxins play in the etiology of ESCC are largely unknown.

METHODS

A mycotoxin biomarker-incorporated, population-based case-control study was performed in Huaian area, Jiangsu Province, one of the two high-risk areas in China. Exposure biomarkers of aflatoxins (AF) and fumonisins (FN) were quantitatively analyzed using HPLC-fluorescence techniques.

RESULTS

Among the cases (n = 190), the median levels of AF biomarker, serum AFB1-lysine adduct, and FN biomarker, urinary FB1, were 1.77 pg/mg albumin and 176.13 pg/mg creatinine, respectively. Among the controls (n = 380), the median levels of AFB1-lysine adduct and urinary FB1 were 1.49 pg/mg albumin and 56.92 pg/mg creatinine, respectively. These mycotoxin exposure biomarker levels were significantly higher in cases as compared to controls (p <  0.05 and 0.01, respectively). An increased risk to ESCC was associated with exposure to both AFB1 and FB1 (p <  0.001 for both).

CONCLUSIONS

Mycotoxin exposure, especially to AFB1 and FB1, was associated with the risk of ESCC, and a greater-than-additive interaction between co-exposures to these two mycotoxins may contribute to the increased risk of ESCC in Huaian area, China.

Aflatoxins in rice: Worldwide occurrence and public health perspectives

Aflatoxins are fungal secondary metabolites that contaminate dietary staples worldwide, including maize, rice and groundnuts. Dietary exposure to aflatoxins is a public health concern due to their carcinogenic, acute and chronic effects. Rice is an important staple food consumed widely and consists of a major part of the diets for half of the world population. Human exposure to these mycotoxins is a serious problem especially in developing countries where hot and humid climates favor the fungal growth and where food storage conditions are poor and lack of regulatory limits enforcement. The recent developments of biomarkers have provided opportunities in assessing aflatoxins exposure and related health effects in the high-risk population groups. This review describes the worldwide occurrence of aflatoxins in rice during the period from 1990 to 2015 and biomarkers-based evidence for human exposure to aflatoxins and their adverse health effects. Aflatoxin is a potent hepatocarcinogen and humans may expose to it at any stage of life. Epidemiological studies reported an association between aflatoxin intake and the incidence of hepatocellular carcinoma in some sub-Saharan and Asian countries. Even daily high intake of rice with a low level of contamination is of health concern. Thus, it is necessary to implement effective strategies to prevent contamination and fungal growth in rice. A good agricultural and manufacturing practice should be applied during handling, storage and distribution of rice to ensure that aflatoxins contamination level is lower in the final product. Moreover, a regular survey for aflatoxins occurrence in rice and biomarkers-based studies is recommended to prevent and reduce the adverse health effects in the world population.

Aflatoxin levels in maize and peanut and blood in women and children: The case of Timor-Leste

Aflatoxins are toxic fungal metabolites produced by Aspergillus sp. with carcinogenic properties that are a common food contaminant of many crops including maize and peanuts. In Timor-Leste malnutrition and children's stunting are frequent and maize and peanuts are staple foods. This study aimed to provide information on aflatoxin exposure nationally. The study measured levels of aflatoxin in locally-produced maize and peanuts (296 samples) and of aflatoxin-albumin conjugate in blood samples of women and young children (514 and 620 respectively) across all municipalities. The average concentration of aflatoxin in the grain samples was low with most maize (88%) and peanut (92%) samples - lower than European Commission tolerated aflatoxin level. Although aflatoxin-albumin conjugate was detected in more than 80% of blood samples, the average concentration in children and adults of 0.64 and 0.98 pg mg^-1 alb, respectively, is much lower than in other similar rural-based countries. Although low in concentration, blood aflatoxin levels and aflatoxin contamination levels in maize across municipalities were correlated significantly for mothers (R² = 37%, n = 495) but not for children (R² = 10%). It is unlikely that the consumption of aflatoxin contaminated grain is a causative factor in the current level of malnutrition and stunting affecting Timor-Leste children.

The Complex Essential Oils Highly Control the Toxigenic Fungal Microbiome and Major Mycotoxins During Storage of Maize

The contamination of maize with fungi and subsequent mycotoxins is a pivotal and long-standing safety concern in the maize industry. In this study, the inhibitory effects of the complex essential oils (cinnamaldehyde, citral, eugenol, and menthol, 3:3:2:2, v/v) on fungal growth and mycotoxins production in stored maize were evaluated using traditional plate counting, internal transcribed spacer 2 (ITS2) sequencing and liquid chromatography-tandem mass spectrometry. Complex essential oils (0.02%) significantly (p < 0.05) reduced the total fungi counts and the content of aflatoxin B₁, zearalenone, and deoxynivalenol in stored maize during 12 months of storage, and were more effective than propionic acid (0.2%). The fungal diversity of the control group was the highest with 113 operational taxonomic units. During storage of maize kernels, Aspergillus, Fusarium, Wallemia, Sarocladium, and Penicillium were main genera. At 0-6 months, the fungal diversity was high and Fusarium was predominant genus. However, at 7-11 months, the fungal diversity was low and Aspergillus was predominant genus. During the later stages of storage, the prevalence of Aspergillus in maize treated with essential oils was significantly lower than (p < 0.05) that observed in the propionic acid treated and control samples. The results of this study suggest that the complex essential oils may be employed successfully to control toxigenic fungi and subsequent contamination with mycotoxins in maize.

Mycotoxin Detection in Maize, Commercial Feed, and Raw Dairy Milk Samples from Assiut City, Egypt

This survey was conducted to investigate the contamination by multiple mycotoxins, aflatoxins (AFB₁, AFB₂, AFG₁, and AFG₂), ochratoxin A (OTA), and zearalenone (ZEA) in 61 samples of maize and 17 commercial animal feed samples, and of aflatoxin M₁ (AFM₁) in raw dairy milk samples (n = 20) collected from Assiut City in Upper Egypt. Multi-mycotoxin immunoaffinity columns were used for samples cleanup and mycotoxin purification. An HPLC–FLD system with an on-line post-column photochemical derivatization was used for the detection of the target toxins. AFB₁ was detected in both maize (n = 15) and feed (n = 8), with only one maize sample presenting a concentration above the maximum permissible level set by the Egyptian authorities. AFB₂ was observed in six maize samples and in one feed sample, with a maximum value of 0.5 μg/kg. ZEA was detected only in feed samples (n = 4), with a maximum value of 3.5 μg/kg, while OTA, AFG₁, and AFG₂ were under the limits of detection. For milk, all the analyzed samples (100%) were contaminated with AFM₁, and 14 samples (70%) presented concentrations above the maximum permissible level in the European Union (EU) (0.05 μg/kg). The concentrations ranged from 0.02 μg/kg to 0.19 μg/kg, except that of one sample, which was under the limit of quantification. The contamination rates in maize and animal feeds are not alarming. In contrast, the consumption of dairy milk samples in Assiut City may pose public health hazards, as AFM₁ levels were found to exceed the international permissible limits. Further surveys are highly recommended in order to establish a database for mycotoxin occurrence in Egypt to minimize the possible health risks in animals and humans.

Occurrence of multiple mycotoxins and other fungal metabolites in animal feed and maize samples from Egypt using LC-MS/MS

BACKGROUND

The present study aimed to investigate the occurrence of multiple toxic fungal and bacterial metabolites in 156 animal feed (n = 77) and maize (n = 79) samples collected from three regions in Upper Egypt. The target analytes were quantified using the 'dilute and shoot' approach, followed by a liquid chromatography tandem mass spectrometry analysis.

RESULTS

In total, 115 fungal and bacterial metabolites were detected in both matrices, including the regulated mycotoxins in the European Union, in addition to the modified forms such as deoxynivalenol-3-glucosid. Furthermore, some Fusarium, Alternaria, Aspergillus and Penicillum metabolites beside other fungal and bacterial metabolites were detected for the first time in Egypt. All of the samples were contaminated with at least four toxins. On average, 26 different metabolites were detected per sample with a trend of more metabolites in feed than in maize. The maximum number of analytes observed per samples was 54 analytes at maximum concentrations ranging from 0.04 µg kg^-1 for tentoxin to 25 040 µg kg^-1 for kojic acid.

CONCLUSION

According to the international standards, the contamination rates in the investigated regions were not alarming, except for AFB1 in maize. The necessity of further and continuous monitoring is highly recommended to establish a database for mycotoxin occurrence. © 2017 Society of Chemical Industry.

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.

Prevalence of aflatoxin and fumonisins (B1 + B2) in maize consumed in rural Malawi

A study was carried out to assess levels of contamination of aflatoxins and fumonisins (B₁ + B₂) in maize produced, stored and consumed in rural households in Malawi. A total of 9 districts were selected across the country representing 3 districts from each of the Northern, Central and Southern regions respectively. Households were selected at random in each district where 10 maize samples were collected for laboratory analysis. Aflatoxins and fumonisins were analyzed using a single step lateral flow immunochromatographic assay based on a competitive immunoassay format. The detection limit for aflatoxins was 2 μg/kg with a quantitation range of 2–150 μg/kg and that for fumonisins was 1 mg/kg with a quantitation range of 1–7 mg/kg. It was found that samples in the Southern region were highly contaminated, with the Chikhwawa district having high levels of both aflatoxins and fumonisins in maize. The Northern region had the least contamination. The maximum detected amount of aflatoxins was 140 μg/kg. The maximum detected amounts of fumonisins was 7 mg/kg. About 20% of maize samples exceeded the tolerable maximum limit for aflatoxins in Malawi. Aflatoxins and fumonisins were found to co-occur with contamination levels exceeding 100 μg/kg for both aflatoxins and fumonisins.

Multi-mycotoxin screening reveals separate occurrence of aflatoxins and ochratoxin a in Asian rice

The determination of important regulated mycotoxins in rice has been reported previously but not in the individual matrix of white, brown, red, and basmati rice with respect to the matrix effect, recovery, and stability. A total of 190 Asian rices were examined for regulated mycotoxin contamination by the LC-ESI-MS/MS method. Significant variation (p < 0.05) in the matrix effect was observed for fumonisins. Methanol improved the limits of detection (LOD) for HT-2 from 50 μg/kg to 2.3 μg/kg by promoting ionization efficiency of the ammonium-adduct. LOD and limits of quantitation ranged from 0.1 to 18 μg/kg and 0.2-31 μg/kg, respectively. All analytes degraded by more than 50% on storage, except fumonisins. Acetic acid (1%) provided significant improvement (p < 0.05) in recovery for all analytes in selected white rice from Thailand and China. Mean recovery ranged from 70 to 120%. RSD values were lower than 15% for all analytes. Five AFB1 and single OTA positive samples were detected. No correlation between mycotoxin contamination and rice species (r = 0) exists.