Occurrence, toxicity, dietary exposure, and management of Alternaria mycotoxins in food and feed: A systematic literature review

Alternaria mycotoxins are emerging contaminants frequently detected in food products and threaten human health. This systematic review aims to provide an up-to-date overview of scientific data and knowledge and gaps therein of natural occurrence, toxicological effects, dietary exposure, and prevention and control management of Alternaria mycotoxins in food and feed. A systematic review has been performed, using the databases Scopus and PubMed, retrieving relevant scientific papers published in English from 2011 to 2024. Alternaria mycotoxins are widely present in various food and feed products, with tomatoes and cereals being the most contaminated products. From the Alternaria mycotoxins, tenuazonic acid (TeA) and alternariol were reported with the highest detection rate and concentrations. Identified toxicological effects vary between the different Alternaria mycotoxins and include carcinogenicity, immune toxicity, cytotoxicity, and genotoxicity. Dietary exposure assessments for Alternaria mycotoxins have been conducted in several countries but vary in their scope. The calculations and risk values suggest that exposure of children to TeA via their diet is close to their tolerable daily intake. A similar finding has been reported for exposure of adults to alternariol and alternariol monomethyl ether via food consumption. Most Alternaria mycotoxins are heat-stable and cannot easily be removed during food processing; therefore, prevention and control measures for Alternaria mycotoxin contamination in food and feed are crucial. Fungicide and biocontrol applications have been shown effective in reducing Alternaria fungal growth and toxin production, and the development of predictive models may be promising. Collectively, they can contribute to mitigating the impact of Alternaria mycotoxins on human health.

Several secondary metabolite gene clusters in the genomes of ten Penicillium spp. raise the risk of multiple mycotoxin occurrence in chestnuts

Penicillium spp. produce a great variety of secondary metabolites, including several mycotoxins, on food substrates. Chestnuts represent a favorable substrate for Penicillium spp. development. In this study, the genomes of ten Penicillium species, virulent on chestnuts, were sequenced and annotated: P. bialowiezense. P. pancosmium, P. manginii, P. discolor, P. crustosum, P. palitans, P. viridicatum, P. glandicola, P. taurinense and P. terrarumae. Assembly size ranges from 27.5 to 36.8 Mb and the number of encoded genes ranges from 9,867 to 12,520. The total number of predicted biosynthetic gene clusters (BGCs) in the ten species is 551. The most represented families of BGCs are non ribosomal peptide synthase (191) and polyketide synthase (175), followed by terpene synthases (87). Genome-wide collections of gene phylogenies (phylomes) were reconstructed for each of the newly sequenced Penicillium species allowing for the prediction of orthologous relationships among our species, as well as other 20 annotated Penicillium species available in the public domain. We investigated in silico the presence of BGCs for 10 secondary metabolites, including 5 mycotoxins, whose production was validated in vivo through chemical analyses. Among the clusters present in this set of species we found andrastin A and its related cluster atlantinone A, mycophenolic acid, patulin, penitrem A and the cluster responsible for the synthesis of roquefortine C/glandicoline A/glandicoline B/meleagrin. We confirmed the presence of these clusters in several of the Penicillium species conforming our dataset and verified their capacity to synthesize them in a chestnut-based medium with chemical analysis. Interestingly, we identified mycotoxin clusters in some species for the first time, such as the andrastin A cluster in P. flavigenum and P. taurinense, and the roquefortine C cluster in P. nalgiovense and P. taurinense. Chestnuts proved to be an optimal substrate for species of Penicillium with different mycotoxigenic potential, opening the door to risks related to the occurrence of multiple mycotoxins in the same food matrix.

Mycological and Multiple Mycotoxin Surveillance of Sorghum and Pearl Millet Produced by Smallholder Farmers in Namibia

Mycological (mycotoxigenic Fusarium and aflatoxigenic Aspergillus spp.) and multiple mycotoxins [aflatoxin B₁ (AFB₁), fumonisin B (FB), deoxynivalenol and zearalenone] surveillance was conducted on raw whole grain sorghum (Sorghum bicolor) and pearl millet (Pennisetum glaucum) produced on smallholder farms, and processed products sold at open markets in northern Namibia. Fungal contamination was determined with morphological methods as well as with quantitative Real-Time PCR (qPCR). The concentrations of multiple mycotoxins in samples were determined with liquid chromatography tandem mass spectrometry. The incidence of mycotoxigenic Fusarium spp., Aspergillus flavus and A. parasiticus, as well as the concentrations of AFB₁ and FB were significantly (P < 0.001) higher in the malts as compared to the raw whole grains, with Aspergillus spp. and AFB₁ exhibiting the highest contamination (P < 0.001). None of the analysed mycotoxins were detected in the raw whole grains. Aflatoxin B₁ above the regulatory maximum level set by the European Commission was detected in sorghum (2 of 10 samples; 20%; 3-11 µg/kg) and pearl millet (6 of 11 samples; 55%; 4-14 µg/kg) malts. Low levels of FB₁ (6 of 10 samples; 60%; 15-245 µg/kg) were detected in sorghum malts and no FB was detected in pearl millet malts. Contamination possibly occurred postharvest, during storage, and/or transportation and processing. By critically monitoring the complete production process, the sources of contamination and critical control points could be identified and managed. Mycotoxin awareness and sustainable education will contribute to reducing mycotoxin contamination. This could ultimately contribute to food safety and security in northern Namibia where communities are exposed to carcinogenic mycotoxins in their staple diet.

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.

Fungal diversity of "solom" a Ghanaian traditional beverage of millet (Pennisetum glaucum)

The association of cereals with fungi cannot be disregarded as their manifestation in our foods poses serious health risks. The aim of this study was to investigate the mycofloral (fungal) and chemical (pH) qualities of the "solom" (beverage of millet) available for consumption from their respective sales points in Ho. "Solom" a cereal beverage of millet was sampled from ten (10) different locations in the Ho Municipality of Ghana and evaluated for their pH, fungal counts, and species diversity. Mycological analyses were done on Oxytetracycline Glucose Yeast Extract (OGYE) and Dichloran Rose Bengal Chloramphenicol (DRBC) media from three (3) points per location using serial dilution. A total of fourteen (14) fungal species belonging to eight (8) genera were isolated on both media; Aspergillus (A. niger, A. flavus, A. fumigatus, A. parasiticus, A. alutaceaus, A. terreus), Rhizopus (R. stolonifer), Mucor (M. racemosus), Fusarium (F. oxysporum), Penicillium (P. digitatum, P. verucosum), Cladosporium (C. cladosporoides), Curvularia (C. lunata), and Rhodotorula sp. were recorded. Fungal counts on both media ranged between 1.68 ± 0.8 and 4.11 ± 0.9 log10 CFU/ml. There were statistically significant (p < .05) differences observed in the samples from different locations. The values of pH recorded were in the range of 3.03 ± 0.09-4.03 ± 0.23 and showed no significant differences (p > .05) among them. All samples were found to be in the acceptable range of values prescribed by the International Commission for Microbiological Specification of Foods (ICMSF, 1998). Good Manufacturing Practices (GMP) and Good Hygiene Practices (GHP) should be employed to enhance food safety.

Current Functionality and Potential Improvements of Non-Alcoholic Fermented Cereal Beverages

Fermentation continues to be the most common biotechnological tool to be used in cereal-based beverages, as it is relatively simple and economical. Fermented beverages hold a long tradition and have become known for their sensory and health-promoting attributes. Considering the attractive sensory traits and due to increased consumer awareness of the importance of healthy nutrition, the market for functional, natural, and non-alcoholic beverages is steadily increasing all over the world. This paper outlines the current achievements and technological development employed to enhance the qualitative and nutritional status of non-alcoholic fermented cereal beverages (NFCBs). Following an in-depth review of various scientific publications, current production methods are discussed as having the potential to enhance the functional properties of NFCBs and their safety, as a promising approach to help consumers in their efforts to improve their nutrition and health status. Moreover, key aspects concerning production techniques, fermentation methods, and the nutritional value of NFCBs are highlighted, together with their potential health benefits and current consumption trends. Further research efforts are required in the segment of traditional fermented cereal beverages to identify new potentially probiotic microorganisms and starter cultures, novel ingredients as fermentation substrates, and to finally elucidate the contributions of microorganisms and enzymes in the fermentation process.

Variation of Fungal Metabolites in Sorghum Malts Used to Prepare Namibian Traditional Fermented Beverages Omalodu and Otombo

Sorghum malts, which are important ingredients in traditional fermented beverages, are commonly infected by mycotoxigenic fungi and mycotoxins may transfer into the beverages, risking consumers’ health. Liquid chromatography–tandem mass spectrometry was used to determine variation of fungal metabolites in 81 sorghum malts processed for brewing of Namibian beverages, otombo (n = 45) and omalodu (n = 36). Co-occurrence of European Union (EU)-regulated mycotoxins, such as patulin, aflatoxins (B₁, B₂, and G₂), and fumonisins (B₁, B₂, and B₃) was detected in both malts with a prevalence range of 2–84%. Aflatoxin B₁ was quantified in omalodu (44%) and otombo malts (14%), with 20% of omalodu malts and 40% of otombo malts having levels above the EU allowable limit. Fumonisin B₁ was quantified in both omalodu (84%) and otombo (42%) malts. Emerging mycotoxins, aflatoxin precursors, and ergot alkaloids were quantified in both malts. Notably, 102 metabolites were quantified in both malts, with 96% in omalodu malts and 93% in otombo malts. An average of 48 metabolites were quantified in otombo malts while an average of 67 metabolites were quantified in omalodu malts. The study accentuates the need to monitor mycotoxins in sorghum malts intended for brewing and to determine their fate in the beverages.

Mycotoxin Contamination of Beverages Obtained from Tropical Crops

This review is mainly centered on beverages obtained from tropical crops, including tea, nut milk, coffee, cocoa, and those prepared from fruits. After considering the epidemiological data found on the matrices above, the focus was given to recent methodological approaches to assess the most relevant mycotoxins. Aspects such as singularities among the mycotoxin and the beverage in which their were found, and the economic effects and repercussions that the mycotoxin-tainted ingredients have on the beverage industry were pointed out. Finally, the burden of their consumption through beverages, including risk and health effects on humans, was addressed as well.