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Abstract
Aflatoxins (AFs) are very important mycotoxins due to their extremely high toxicity, carcinogenic activity for animals (including humans), and frequent occurrence in various foods and feedstuffs. AFB1, AFB2, AFG1, and AFG2 are especially important AFs. The AFB, is well known as one of the most carcinogenic compounds. AF-M group are metabolites of AF-B group in feeds for cattle. Ingested AFB1 is converted to AFM1 in the cow's liver.The regulations on AFs have been established in many countries, with the maximum levels ranging from 1 to 20μg kg⁻¹ for AFB1 and from 0 to 15μg kg⁻¹ for AFM1. Because AFM1 is a metabolite of AFB1, regulation on AFB1 in feed for cattle is most effective for controlling AFM1 in milk.AFs are found in nuts, cereals, spices, dairy products, and the like. The contamination levels in commercial foods vary with natural and artificial causes.Because detoxification or elimination of AFs in foods is hardly possible, efforts to avert the occurrence of AFs in foods are important.Sterigmatocystin, a precursor of AFs, is also toxic and carcinogenic, but much less toxic than AFB1.
... Upon ingestion by lactating animals the AFB toxins are converted to the AFM metabolites in the liver and ca. 0.9% of ingested AFB 1 is found in the milk as the hydroxylated metabolite AFM 1 (Tabata 2011). The occurrence of AFM 1 in milk, especially bovine milk, is of particular concern for public health because of the importance of cows' milk as a foodstuff for children and adults. ...
... In the EU, the maximum limit for AFM 1 in milk is set at 0.05 µg/Kg (Commission Regulation (EC) No 1881. Chromatographic and ELISA methods are used for the determination of the AF content of raw milk (Tabata 2011). AFs are particularly heat tolerant. ...
... There are only a few accounts of STC occurring spontaneously, despite the fact that fungi capable of making STC are ubiquitous all over the world. In a focused study by Tabata (2011), STC was not detected in harvested grains or cheese but was found to be present in preserved products. STC has been detected in oregano, up to 28.0 µg/kg from Turkey, in thyme up to 14.0 µg/kg from Poland (Reinholds et al., 2017), and in paprika, 18.0 µg/kg from South Africa (Motloung et al., 2018). ...
Spices are typically grown in climates that support the growth of toxigenic fungi and the production of mycotoxins. The Aspergilli described in this study, as well as the sterigmatocystin (STC) detected, are causes for concern due to their potential to induce food poisoning. One of the most well-known producers of the carcinogenic STC is Aspergillus nidulans . This research explores the occurrence of STC-producing fungi in Foeniculum vulgare , a spice that is marketed in India and other parts of the world. This innovative study details the mycotoxigenic potential of five Aspergilli belonging to Section Nidulantes , namely Aspergillus latus (02 isolates), Emericella quadrilineata (02 isolates), and Aspergillus nidulans (01 isolate), with respect to STC contamination. These five isolates of Aspergilli were screened to produce STC on yeast extract sucrose (YES) medium in a controlled environment with regard to light, temperature, pH, and humidity, among other variables. The expression patterns of regulatory genes, namely, aflR , laeA , pacC , fluG , flbA , pksA , and mtfA were studied on the Czapek–Dox agar (CDA) medium. STC biosynthesis by the test isolates was done in potato dextrose broth (PDB) under optimum conditions, followed by the extraction and purification of the broth using ethyl acetate. High-performance liquid chromatography (HPLC) with an ultraviolet (UV) detector was utilized to detect compounds in eluted samples. F. vulgare contains Aspergilli that have been shown to have mycotoxigenic potential, which can accumulate in the spice during its active growth and thereby cause the elaboration of mycotoxins.
... AFB1 was the most carcinogenic and it was usually produced in the highest amount among the others, while AFB2 and AFG2 were produced only one-tenth and one-third of the total number of the AFB1 and AFG1. The presence of double bonds at the furan ring terminal was the main factor determining the toxicity and carcinogenic level of aflatoxins [17]. The increase of aflatoxin was caused by some environmental factors which supported the Aspergillus flavus to produce aflatoxin. ...
In the long term, fungi attacks will cause a decrease in the quality of corn during storage. In this case, Aspergillus flavus and Aspergillus parasiticus have become a serious concern related to food safety because of their ability to produce aflatoxins which are toxic to humans and animals. Nowadays, feed industries use fungicides to control fungal infections before the storage period due to their affordability, but the chemical residues are detrimental to our health. Therefore, an alternative method was needed to prevent and control fungi and aflatoxin formation in corn. One of the potential methods to apply is the gaseous ozonization. This research was conducted to investigate the potential of ozone in preventing fungal attacks and aflatoxin formation in corn, assuring that the corn quality can be maintained during the storage period. The objective of this study was to determine the effect of ozone on maintaining the quality of corn during storage, especially to reduce fungi colonies and aflatoxin formation. The experimental design used in this study was a completely randomized design with two treatment factors, namely temperature (20, 30, and 40°C) and exposure time (30 and 60 minutes). Corn quality parameters observed include moisture content, total fungal, moldy kernels, damaged kernels, and aflatoxin (AFB1, AFB2, AFG1, AFG2) contamination. The results showed that ozone treatment had an effect on reducing total fungal and aflatoxin contamination in corn, however, it had no effect on the moisture content, moldy kernels, and damaged kernels of corn. The optimum effect was obtained when the ozonization was conducted at a temperature of 20°C for 60 minutes exposure time, which results in the highest reduction in total fungal and total aflatoxin contamination of 36.77% and 92.45% respectively.
... It has been noted that A. versicolor is the major ST producer (Tabata, 2011). Zhao et al. (2018) determined the occurrence of ST in 178 food samples (32 wheat samples and 146 wheat products) purchased from Chinese supermarkets. ...
Aspergillus strains were isolated from Hungarian mills in order to get information on the appearance of sterigmatocystin (ST) producing moulds, whose presence has never been demonstrated in Hungary. Fungal isolates were classified into nine morphotypes, sections Nigri , Nidulantes , Versicolores (two morphotypes), Circumdati , Flavi (two morphotypes), Clavati and Terrei by classical mycological assays. ST producing strains could be classified into section Versicolores . ST production of the isolates was assessed by liquid and solid phase growth experiments and compared to ST producing reference strains: Aspergillus pepii SzMC 22332, Aspergillus versicolor SzMC 22333, Aspergillus griseoaurantiacus SzMC 22334 and Aspergillus nidulans RDIT9.32. Four of our isolates marked as Km11, Km14, Km26 and Km31 showed ST production in liquid medium. ST production on solid phase corn grit substrate was measured after three weeks of incubation, and Km26 isolate proved to be the most prominent with a toxin concentration of 277.1 μg g ⁻¹ , surpassing all reference strains. The toxin-producing ability of Km26 isolate was also tested in a field experiment, where corn was infected. By the end of the experiment, ST level of 19.56 μg kg ⁻¹ was measured in infected corn.
Molecular taxonomic identification of the Km26 strain was performed using internal transcribed spacer (ITS), calmodulin and tubulin sequence analyses. Based on these studies, strain Km26 was identified as Aspergillus creber .
Here we report that an ST-producing A. creber strain has appeared in Hungary, and the Km26 strain is the first known extreme ST-producing mould in this country. As a result of climate change, aflatoxin B1 producing Aspergillus flavus strains have appeared in Hungary in the last decade. As strain Km26 is the only A. creber isolate in Hungary so far, there is no sign of mass prevalence, and due to the lower temperature optimum of the species compared to A. flavus , its appearance is probably not related to climate change.
... The consumption of mycotoxins can cause pathologies, such as kidney damage, gastrointestinal and reproductive disorders, carcinogenic effects, suppression of the immune system, and even death in fishes (Anater et al. 2016). Aflatoxins represent one of the most important types of mycotoxins due to their high toxicity and carcinogenic activity in animals (Tabata 2011). These are produced, to a greater extent, by fungi belonging to the Flavi group of the genus Aspergillus, such as Aspergillus flavus, A. parasiticus, and A. nomius, which have been isolated from peanuts, corn, spices, nuts, beans, and sugarcane (Fujimoto 2011). ...
In the aquaculture industry, the selection and quality of feed are highly relevant because their integrity and management have an impact on the health and development of organisms. In general, feeds contamination depends on storage conditions and formulation. Furthermore, it has been recognized that filamentous fungi are among the most important contaminating agent in formulated feeds. Therefore, the purpose of this research was to identify saprophytic fungi capable of proliferating in commercial feeds, as well as determining their prevalence, extracellular enzymes profile, ability to assimilate carbon sources, and finally their ability to produce aflatoxins. In order to do that, twenty-two fungi were isolated from commercial fish feeds. After, the species Aspergillus chevalieri, A. cristatus, A. sydowii, A. versicolor, A. flavus, A. creber, and Lichtheimia ramosa were identified. These fungi were able to produce extracellular enzymes, such as phosphatases, esterases, proteases, β-glucosidase, and N-acetyl-β-glucosaminidase. The isolated fungi showed no selective behavior in the assimilation of the different carbon sources, showing a strong metabolic diversity. Prevalence percentages above 85% were recorded. Among all fungi studied, A. flavus M3-C1 had the highest production of aflatoxins when this strain was inoculated directly in the feeds (295 ppb). The aflatoxin production by this strain under the experimental setting is above the permitted levels, and it has been established that high levels of aflatoxins in feeds can cause alterations in fish growth as well as the development of cancerous tumors in the liver, in addition to enhancing mortality.
... Aflatoxins (AFs) are produced mainly by Aspergillus flavus and A. parasiticus (Tabata, 2011). As highly toxic secondary metabolites, AFs are carcinogenic, teratogenic and hepatotoxic to both humans and animals (Marin, Ramos, Cano-Sancho, & Sanchis, 2013). ...
... This was when 100,000 turkeys died as a result of toxin contamination caused by Aspergillus flavus (Quadri et al., 2013). The AFs are predominantly produced by two Aspergillus species, i.e A. parasiticus and A. flavus (Tabata, 2011). Aflatoxins are bis-furan metabolites and 18 different types have been identified (Marin et al., 2013) exhibited by the AFM groups is due to the steric hindrances, chirality and resonance energy of the cyclopentenone ring of the B series, as compared to the six-membered lactone ring of the G series (Haschek and Voss, 2013). ...
Aflatoxin (AF) contamination presents one of the most insidious challenges to combat, in food safety. Its adulteration of agricultural commodities presents an important safety concern as evident in the incidences of its health implication and economic losses reported widely. Due to the overarching challenges presented by the contamination of aflatoxins (AFs) in foods and feeds, there is an urgent need to evolve cost-effective and competent strategies to combat this menace. In our review, we tried to appraise the cost-effective methods for decontamination of aflatoxins AFs. We identified the missing links in adopting microbial degradation as a palliative to decontamination of aflatoxins AFs and its commercialization in food industries. Cogent areas of further research were also highlighted in the review paper.
The term “emerging mycotoxins” was coined in 2008 for lesser-known Fusarium metabolites, fusaproliferin, enniatins, beauvericin, and moniliformin. The emerging mycotoxins and their derivatives can occur in high concentrations and high frequency in cereals, cereal-based products, fruits, processed and unprocessed/raw food, animal feed, and feeding stuffs. Some of them are carried over in animal-derived products. Notwithstanding the high prevalence, determination and legislative regulations of emerging mycotoxins are confined to Europe and the Mediterranean. Since many emerging mycotoxins are more or less toxic to the consumers, their importance to food safety is not addressed properly. In view of this, the present chapter focuses on some emerging or minor mycotoxins produced by Aspergillus spp., Penicillium spp., Fusarium spp., and Alternaria spp.
The aim of this study was to evaluate the influence of combining extrusion and fermentation processes on the chemical and biosafety of wheat processing by-products (WPBP). Extrusion experiments were performed by testing two different temperatures (115 and 130°C) and three different speeds of extruder screw (16, 20, and 25 rpm). The lactic acid bacteria (LAB) L. casei and L. paracasei were used for WPBP fermentation. A high-performance liquid chromatograph coupled to a triple quadrupole mass spectrometer was used for mycotoxin analysis and a high-performance liquid chromatograph with a ultraviolet detector was used for biogenic amine (BA) determination in WPBP. A significant effect of the type of LAB on the acidity of fermented WPBP was found. Although lower pH was observed for non-extruded fermented WPBP samples, they contained higher concentrations of D(-)-lactic acid. In extruded and extruded/fermented WPBP, the total BA content was two times lower than that in controls. The lowest mycotoxin concentration was found in fermented WPBP extruded at 130°C using a screw speed of 20 and 25 rpm. Finally, the combination of extrusion and fermentation can be confirmed as a promising innovative pre-treatment for WPBP, potentially capable of reducing the content of BAs and mycotoxins.
Multiple mycotoxins were tested in milled rice samples (n = 200) from traders at different milling points within the Mwea Irrigation Scheme in Kenya. Traders provided the names of the cultivar, village where paddy was cultivated, sampling locality, miller, and month of paddy harvest between 2018 and 2019. Aflatoxin, citrinin, fumonisin, ochratoxin A, diacetoxyscirpenol, T2, HT2, and sterigmatocystin were analyzed using ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS). Deoxynivalenol was tested using enzyme-linked immunosorbent assay (ELISA). Mycotoxins occurred in ranges and frequencies in the following order: sterigmatocystin (0–7 ppb; 74.5%), aflatoxin (0–993 ppb; 55.5%), citrinin (0–9 ppb; 55.5%), ochratoxin A (0–110 ppb; 30%), fumonisin (0–76 ppb; 26%), diacetoxyscirpenol (0–24 ppb; 20.5%), and combined HT2 + T2 (0–62 ppb; 14.5%), and deoxynivalenol was detected in only one sample at 510 ppb. Overall, low amounts of toxins were observed in rice with a low frequency of samples above the regulatory limits for aflatoxin, 13.5%; ochratoxin A, 6%; and HT2 + T2, 0.5%. The maximum co-contamination was for 3.5% samples with six toxins in different combinations. The rice cultivar, paddy environment, time of harvest, and millers influenced the occurrence of different mycotoxins. There is a need to establish integrated approaches for the mitigation of mycotoxin accumulation in the Kenyan rice.
Mycotoxins are a group of toxins of low molecular weight. They are natural toxins produced as secondary fungal metabolites. It is estimated that about 400 mycotoxins exist and about 20 classes of them are known to cause health concerns in both humans and animals worldwide. Major food commodities affected by mycotoxins are cereals, nuts, dried fruits, coffee, cocoa, spices, oilseeds, and some derived products such as beer, wine, and fruit juices. Mycotoxins also enter the human food chain via meat or other animal products such as milk and cheese as a result of livestock eating contaminated feed. Among the most important mycotoxins are the aflatoxins (AFs) which are produced mainly by Aspergillus flavus, Aspergillus parasiticus, and Aspergillus nomius. AFs consist of a group of ~20 related fungal metabolites, although only AFB1, AFB2, AFG1, and AFG2 are normally found in foods; the metabolites M1 from AFB1 and M2 from AFB2 are found in animal products. AFB1 can be found at the highest concentrations in some food crops and is a genotoxic carcinogen that may cause serious health effects in both humans and animals. This article will provide basic information on AFs and their occurrence, toxicity, analytical techniques, regulation, and detoxification.
Subsamples of a given lot of peanuts may vary greatly in aflatoxin content due to extreme variability in the degree of contamination
of individual kernels. A micro method, adapted from the aqueous acetone procedure recently proposed by Pons and Goldblatt
for the determination of aflatoxins in cottonseed products, was developed to permit accurate determination of aflatoxins in
individual kernels and kernel sections.
Use of this procedure permitted the topographic distribution of aflatoxins within single kernels to be mapped and indicated
that the toxins are not uniformly distributed within contaminated kernels, even when the kernel contains a high level of aflatoxins.
Although wrinkling or discoloration sometimes indicated that a kernel was contaminated, this type of physical damage was not
found to be a reliable indication of aflatoxin content. Also it was noted that a few apparently sound and mature kernels contained
high levels of aflatoxins.
Aflatoxins are highly toxic and carcinogenic substances mainly produced by Aspergillus flavus
and Aspergillus parasiticus. Sterigmatocystin is a penultimate precursor of aflatoxins and also a toxic and carcinogenic substance produced by many species, including Aspergillus nidulans. Recently, the majority of the enzyme reactions involved in aflatoxin/sterigmatocystin biosynthesis have been clarified, and the genes encoding the enzymes have been isolated. Most of the genes constitute a large gene cluster in the fungal genome, and their expression is mostly regulated by a product of the regulatory gene aflR. This review will summarize the enzymatic steps and the genes in aflatoxin/sterigmatocystin biosynthesis.