Co-occurrence of aflatoxins, ochratoxin A and citrinin in “egusi” melon (Colocynthis citrullusL.) seeds consumed in Ireland and the United Kingdom

Gold nanoparticle-mediated fluorescence immunoassay for rapid and sensitive detection of Ochratoxin A

In this work, a fluorescence immunoassay based on horseradish peroxidase-labeled IgG (HRP-IgG)-modified gold nanoparticle (AuNP@HRP-IgG) probe was established for detection of ochratoxin A (OTA). Through the catalysis of HRP, the dopamine (DA) and 1,5-dihydroxynaphthalene (DHA) can rapidly generate azamonardine fluorescence compound (AFC) with intense yellow fluorescence. Large amounts of AFC can be formed within 4 min, which led to fluorescence enhancement at 545 nm. This new method displayed high sensitivity with a limit of detection (LOD) of 0.18 ng/mL and a linear range of 0.78-200 ng/mL for OTA. Meanwhile, the recoveries of OTA in corn samples were 101.41% - 113.45%. Due to the universality of the probe and the rapidity of signal output, the fluorescence immunoassay allowed rapid and sensitive detection of targets.

Updates on food and feed mycotoxin contamination and safety in Africa with special reference to Nigeria

Mycotoxin contamination of food and feed is a major concern in sub-Sahara African countries, particularly Nigeria. It represents a significant limit to health of human, livestock as well as the international trade. Aflatoxins, fumonisins, ochratoxin, zearalenone, deoxynivalenol and beauvericin are the major mycotoxins recognised in the aetiology of food safety challenges that precipitated countless number of diseases. In Nigeria, aflatoxins and fumonisin found in nearly all crops are the most common mycotoxins of economic and health importance such as sorghum, maize and groundnuts. Thus, consumption of food contaminated with mycotoxins are inevitable, hence the need for adequate regulation is necessary in these frontier economies as done in many developed economies to ensure food safety for human and animals. In low and middle-income countries, especially Nigeria, there is lack of awareness and sufficient information on the risk associated with consequent of mycotoxin contamination on wellbeing of human, animals health and the economy. It is based on the foregoing that this paper summarized the status of mycotoxin present in Nigerian food and feeds relative to the global regulatory standards. This aimed at preventing consuming mycotoxin contaminated food stuff while confronting its associated challenges. Suggestions on some possible control strategies to mitigate vending mycotoxin food and feeds were made.

Amelioration of pulmonary aflatoxicosis by green tea extract: An in vivo study

Aflatoxins (AFB₁) are mycotoxins known to be associated with human and animal diseases. The lung is a at risk from AFB₁exposure either via inhalation or circulation. Green tea consumption is increasing over time due to widespread popularity as antioxidants, anti-inflammatory, and cytoprotective agents. Therefore, we attempted to study the lung toxicity caused by AFB₁ and the possible ameliorating effect of green tea extract. Forty adult male albino rats were divided into five groups; Group I: Untreated control group, Group II (vehicle): Each rat received 1 ml of olive oil, Group III (GTE): Each rat received Camellia sinensis, green tea extract (30 mg/kg/day), Group IV(AFB₁): Each rat received (50 μg/kg/day of AFB₁). Group V (AFB₁+ GTE): Each rat received the same previously mentioned doses of AFB1 in addition to GTE concomitantly. All treatments were orally gavaged for 8 weeks then rats were sacrificed. Serum levels of pro-inflammatory (IL-1β, TNF-α, IL-6) and anti-inflammatory (IL-10) cytokines were measured, lung tissues' oxidative stress indices were also measured in addition to the histopathological study which was performed by using hematoxylin & eosin and Masson trichrome stains. Morphometric and statistical analyses were also performed. Oral gavage of AFB₁ resulted in significant histopathological changes in the lung tissues, in the form of variable degrees of congestion, hemorrhage, interstitial inflammation with infiltration by chronic inflammatory cells, interstitial fibrosis, bronchitis, vasculitis and fibrous thickening of arterial walls. Inflammation was evident by elevated levels of pro-inflammatory cytokines and a declined level of anti-inflammatory cytokines. Also, oxidative stress was evident by increased levels of Malondialdehyde (MDA), Myeloperoxidase (MPO), and decreased levels of total glutathione (tGSH) and Catalase (CAT). The histopathological changes, inflammatory cytokines, and oxidative stress markers were significantly decreased during concomitant administration of green tea extract in (AFB₁+ GTE) group. Aflatoxin B₁ has deleterious effects on the lung tissue that could be minimized by concomitant administration of Green tea extract owing to its anti-inflammatory, antioxidant, and protective properties.

Distribution of fungi and their toxic metabolites in melon and sesame seeds marketed in two major producing states in Nigeria

In this study, melon (n = 60) and sesame (n = 60) seeds purchased from markets within Benue and Nasarawa states, respectively, in Nigeria, during two seasons (dry and wet), were analysed for fungal and mycotoxin contamination in order to determine the safety of these foods for human consumption. Molecular analysis revealed the following seven fungal taxonomic groups in the foods: Aspergillus section Candidi, Aspergillus section Flavi, Aspergillus section Nigri, Cladosporium, Fusarium fujikuroi species group, Penicillium, and Pleosporales/Didymellaceae. A total of 78 microbial metabolites, including several mycotoxins, occurred in the foods. The most frequent mycotoxins in melon and sesame were aflatoxin B1 (occurrence: 76%) and alternariol monomethyl ether (occurrence: 59%), respectively. However, higher mean total aflatoxin levels occurred in sesame (17 μg kg-1) than in melon (11 μg kg-1). About 28 and 5% of melon and sesame, respectively, exceeded the 4 μg kg-1 total aflatoxin limit for oilseeds intended for direct human consumption in the European Union. Additionally, fumonisin B1 and moniliformin occurred only in sesame, whilst ochratoxins A and B occurred only in melon; ochratoxin B being reported for the first time in this food. Our data indicated seasonal variations in the fungal and mycotoxin contamination levels in both foods.

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.

Aflatoxins in sunflower seeds and unrefined sunflower oils from Singida, Tanzania

A total of 61 samples comprising sunflower seeds (40) and unrefined sunflower oils (21) samples collected randomly from Singida, Tanzania were analysed by Reverse Phase-high performance liquid chromatography (RP-HPLC). 15% (6/40) of the seed samples were contaminated with aflatoxin B₁ ranging from limit of detection (LOD) to 218 ng g^-1 with three of them exceeding the European Commission/European Union (EC/EU) and Tanzania Bureau of Standards (TBS)/Tanzania Food and Drug Authority (TFDA) maximum limits of 2 ng g^-1 for AFB₁ in oilseeds. The levels of total aflatoxins (AFT) in seeds ranged from LOD to 243 ng g^-1. Other aflatoxins, except AFG₂, were also detected. For the unrefined sunflower oils, the levels of AFB₁ ranged from LOD to 2.56 ng mL^-1. About 80.9% (17/21) of the analysed oil samples contained AFB₁ of which 17.65% (3/17) exceeded the EC/EU and TBS/TFDA maximum limits of 2 ng mL^-1. Other aflatoxins were also detected in the oils. The measured levels indicate there is a need for food quality education among food processors.

Engaging One Health for Non-Communicable Diseases in Africa: Perspective for Mycotoxins

The role of mycotoxins-e.g., aflatoxins, ochratoxins, trichothecenes, zearalenone, fumonisins, tremorgenic toxins, and ergot alkaloids-has been recognized in the etiology of a number of diseases. In many African countries, the public health impact of chronic (indoor) and/or repeated (dietary) mycotoxin exposure is largely ignored hitherto, with impact on human health, food security, and export of African agricultural food products. Notwithstanding, African scientific research reached milestones that, when linked to findings gained by the international scientific community, make the design and implementation of science-driven governance schemes feasible. Starting from Nigeria as leading African Country, this article (i) overviews available data on mycotoxins exposure in Africa; (ii) discusses new food safety issues, such as the environment-feed-food chain and toxic exposures of food producing animals in risk assessment and management; (iii) identifies milestones for mycotoxins risk management already reached in West Africa; and (iv) points out preliminary operationalization aspects for shielding communities from direct (on health) and indirect (on trade, economies, and livelihoods) effects of mycotoxins. An African science-driven engaging of scientific knowledge by development actors is expected therefore. In particular, One health/One prevention is suggested, as it proved to be a strategic and sustainable development framework.

Comparative Transcriptome Analysis of Penicillium citrinum Cultured with Different Carbon Sources Identifies Genes Involved in Citrinin Biosynthesis

Citrinin is a toxic secondary metabolite of Penicillium citrinum and its contamination in many food items has been widely reported. However, research on the citrinin biosynthesis pathway and its regulation mechanism in P. citrinum is rarely reported. In this study, we investigated the effect of different carbon sources on citrinin production by P. citrinum and used transcriptome analysis to study the underlying molecular mechanism. Our results indicated that glucose, used as the sole carbon source, could significantly promote citrinin production by P. citrinum in Czapek’s broth medium compared with sucrose. A total of 19,967 unigenes were annotated by BLAST in Nr, Nt, Swiss-Prot and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Transcriptome comparison between P. citrinum cultured with sucrose and glucose revealed 1085 differentially expressed unigenes. Among them, 610 were upregulated while 475 were downregulated under glucose as compared to sucrose. KEGG pathway and Gene ontology (GO) analysis indicated that many metabolic processes (e.g., carbohydrate, secondary metabolism, fatty acid and amino acid metabolism) were affected, and potentially interesting genes that encoded putative components of signal transduction, stress response and transcription factor were identified. These genes obviously had important impacts on their regulation in citrinin biosynthesis, which provides a better understanding of the molecular mechanism of citrinin biosynthesis by P. citrinum.

Survey of Penicillia associated with Italian grana cheese

The present work aimed to contribute information on the mycobiota associated with ripening grana cheese, with focus on the genus Penicillium as potential mycotoxin producers. Eighteen wheels of grana cheese, aged in different storehouses situated in Northern Italy, were sampled to isolate associated fungi. Penicillium spp. were commonly dominant; morphological observation and gene sequencing were applied to identify Penicillium at species level. P. crustosum and P. solitum were the dominant species. Citrinin and ochratoxin A mycotoxins were analysed and the latter was found in all grana cheese samples. These results confirmed that a polyphasic approach is mandatory for Penicillium identification at species level.

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.