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Ochratoxins are a group of mycotoxins produced by some Aspergillus species (mainly A. ochraceus and A. carbonarius, but also by 33% of A. niger industrial strains) and some Penicillium species, especially P. verrucosum. Ochratoxin A is the most prevalent and relevant fungal toxin of this group, while ochratoxins B and C are of lesser importance.
Ochratoxin A is known to occur in commodities such as cereals, coffee, dried fruit, and red wine. It is possibly a human carcinogen and is of special interest as it can be accumulated in the meat of animals. Exposure to ochratoxins through diet can cause acute toxicity in mammalian kidneys. Exposure to ochratoxin A has been associated with Balkan endemic nephropathy, a kidney disease with high mortality in people living near tributaries of the Danube River in Eastern Europe. [1]
It has been suggested that carriers of alleles associated with phenylketonuria may have been protected from spontaneous abortion caused by ochratoxin exposure, providing a heterozygous advantage for the alleles despite the possibility of severe intellectual disability in the more rare instance of inheritance from both parents. [2] [3]
A mold or mould is one of the structures that certain fungi can form. The dust-like, colored appearance of molds is due to the formation of spores containing fungal secondary metabolites. The spores are the dispersal units of the fungi. Not all fungi form molds. Some fungi form mushrooms; others grow as single cells and are called microfungi.
Aflatoxins are various poisonous carcinogens and mutagens that are produced by certain molds, particularly Aspergillus species. The fungi grow in soil, decaying vegetation and various staple foodstuffs and commodities such as hay, sweetcorn, wheat, millet, sorghum, cassava, rice, chili peppers, cottonseed, peanuts, tree nuts, sesame seeds, sunflower seeds, and various spices. In short, the relevant fungi grow on almost any crop or food. When such contaminated food is processed or consumed, the aflatoxins enter the general food supply. They have been found in both pet and human foods, as well as in feedstocks for agricultural animals. Animals fed contaminated food can pass aflatoxin transformation products into eggs, milk products, and meat. For example, contaminated poultry feed is the suspected source of aflatoxin-contaminated chicken meat and eggs in Pakistan.
Mothballs are small balls of chemical pesticide and deodorant, sometimes used when storing clothing and other materials susceptible to damage from silverfish, mold or moth larvae.
A mycotoxin is a toxic secondary metabolite produced by fungi and is capable of causing disease and death in both humans and other animals. The term 'mycotoxin' is usually reserved for the toxic chemical products produced by fungi that readily colonize crops.
T-2 mycotoxin is a trichothecene mycotoxin. It is a naturally occurring mold byproduct of Fusarium spp. fungus which is toxic to humans and animals. The clinical condition it causes is alimentary toxic aleukia and a host of symptoms related to organs as diverse as the skin, airway, and stomach. Ingestion may come from consumption of moldy whole grains. T-2 can be absorbed through human skin. Although no significant systemic effects are expected after dermal contact in normal agricultural or residential environments, local skin effects can not be excluded. Hence, skin contact with T-2 should be limited.
Fumonisin B1 is the most prevalent member of a family of toxins, known as fumonisins, produced by several species of Fusarium molds, such as Fusarium verticillioides, which occur mainly in maize (corn), wheat and other cereals. Fumonisin B1 contamination of maize has been reported worldwide at mg/kg levels. Human exposure occurs at levels of micrograms to milligrams per day and is greatest in regions where maize products are the dietary staple.
The trichothecenes are a large family of chemically related mycotoxins. They are produced by various species of Fusarium, Myrothecium, Trichoderma/Podostroma, Trichothecium, Cephalosporium, Verticimonosporium, and Stachybotrys. Chemically, trichothecenes are a class of sesquiterpenes.
Ochratoxin A—a toxin produced by different Aspergillus and Penicillium species — is one of the most-abundant food-contaminating mycotoxins. It is also a frequent contaminant of water-damaged houses and of heating ducts. Human exposure can occur through consumption of contaminated food products, particularly contaminated grain and pork products, as well as coffee, wine grapes, and dried grapes. The toxin has been found in the tissues and organs of animals, including human blood and breast milk. Ochratoxin A, like most toxic substances, has large species- and sex-specific toxicological differences.
Citrinin is a mycotoxin which is often found in food. It is a secondary metabolite produced by fungi that contaminates long-stored food and it causes different toxic effects, like nephrotoxic, hepatotoxic and cytotoxic effects. Citrinin is mainly found in stored grains, but sometimes also in fruits and other plant products.
Mycotoxicology is the branch of mycology that focuses on analyzing and studying the toxins produced by fungi, known as mycotoxins. In the food industry it is important to adopt measures that keep mycotoxin levels as low as practicable, especially those that are heat-stable. These chemical compounds are the result of secondary metabolism initiated in response to specific developmental or environmental signals. This includes biological stress from the environment, such as lower nutrients or competition for those available. Under this secondary path the fungus produces a wide array of compounds in order to gain some level of advantage, such as incrementing the efficiency of metabolic processes to gain more energy from less food, or attacking other microorganisms and being able to use their remains as a food source.
Sterigmatocystin is a polyketide mycotoxin produced by certain species of Aspergillus. The toxin is naturally found in some cheeses.
Vomitoxin, also known as deoxynivalenol (DON), is a type B trichothecene, an epoxy-sesquiterpenoid. This mycotoxin occurs predominantly in grains such as wheat, barley, oats, rye, and corn, and less often in rice, sorghum, and triticale. The occurrence of deoxynivalenol is associated primarily with Fusarium graminearum and F. culmorum, both of which are important plant pathogens which cause fusarium head blight in wheat and gibberella or fusarium ear blight in corn. The incidence of fusarium head blight is strongly associated with moisture at the time of flowering (anthesis), and the timing of rainfall, rather than the amount, is the most critical factor. However, increased amount of moisture towards harvest time has been associated with lower amount of vomitoxin in wheat grain due to leaching of toxins. Furthermore, deoxynivalenol contents are significantly affected by the susceptibility of cultivars towards Fusarium species, previous crop, tillage practices, and fungicide use. It occurs abundantly in grains in Norway due to heavy rainfall.
Microbial toxins are toxins produced by micro-organisms, including bacteria, fungi, protozoa, dinoflagellates, and viruses. Many microbial toxins promote infection and disease by directly damaging host tissues and by disabling the immune system. Endotoxins most commonly refer to the lipopolysaccharide (LPS) or lipooligosaccharide (LOS) that are in the outer plasma membrane of Gram-negative bacteria. The botulinum toxin, which is primarily produced by Clostridium botulinum and less frequently by other Clostridium species, is the most toxic substance known in the world. However, microbial toxins also have important uses in medical science and research. Currently, new methods of detecting bacterial toxins are being developed to better isolate and understand these toxins. Potential applications of toxin research include combating microbial virulence, the development of novel anticancer drugs and other medicines, and the use of toxins as tools in neurobiology and cellular biology.
Aflatoxin B1 is an aflatoxin produced by Aspergillus flavus and A. parasiticus. It is a very potent carcinogen with a TD50 3.2 μg/kg/day in rats. This carcinogenic potency varies across species with some, such as rats and monkeys, seemingly much more susceptible than others. Aflatoxin B1 is a common contaminant in a variety of foods including peanuts, cottonseed meal, corn, and other grains; as well as animal feeds. Aflatoxin B1 is considered the most toxic aflatoxin and it is highly implicated in hepatocellular carcinoma (HCC) in humans. In animals, aflatoxin B1 has also been shown to be mutagenic, teratogenic, and to cause immunosuppression. Several sampling and analytical methods including thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), mass spectrometry, and enzyme-linked immunosorbent assay (ELISA), among others, have been used to test for aflatoxin B1 contamination in foods. According to the Food and Agriculture Organization (FAO), a division of the United Nations, the worldwide maximum tolerated levels of aflatoxin B1 was reported to be in the range of 1–20 μg/kg (or .001 ppm - 1 part-per-billion) in food, and 5–50 μg/kg (.005 ppm) in dietary cattle feed in 2003.
Riddelliine is a chemical compound classified as a pyrrolizidine alkaloid. It was first isolated from Senecio riddellii and is also found in a variety of plants including Jacobaea vulgaris, Senecio vulgaris, and others plants in the genus Senecio.
Many species of fungi produce secondary metabolites called mycotoxins. These toxins can be very detrimental to both humans and animals. The side-effects of ingesting these toxic substances are called mycotoxicosis, which can be a variety of medical conditions. The most common fungi that produce mycotoxins include Fusarium, Aspergillus, and Penicillium.
Aspergillus ochraceus is a mold species in the genus Aspergillus known to produce the toxin ochratoxin A, one of the most abundant food-contaminating mycotoxins, and citrinin. It also produces the dihydroisocoumarin mellein. It is a filamentous fungus in nature and has characteristic biseriate conidiophores. Traditionally a soil fungus, has now began to adapt to varied ecological niches, like agricultural commodities, farmed animal and marine species. In humans and animals the consumption of this fungus produces chronic neurotoxic, immunosuppressive, genotoxic, carcinogenic and teratogenic effects. Its airborne spores are one of the potential causes of asthma in children and lung diseases in humans. The pig and chicken populations in the farms are the most affected by this fungus and its mycotoxins. Certain fungicides like mancozeb, copper oxychloride, and sulfur have inhibitory effects on the growth of this fungus and its mycotoxin producing capacities.
2-Aminofluorene (2-AF) is a synthetic arylamine. It is a white to tan solid with a melting point of 125-132 °C. 2-AF has only been tested in controlled laboratory settings thus far. There is no indication that it will be tested in industrialized settings. There is evidence that 2-aminofluorene is a carcinogen and an intercalating agent that is extremely dangerous to genomic DNA that potentially can lead to mutation if not death. Furthermore, it has been suggested that 2-aminofluorene can undergo acetylation reactions that causes these reactive species to undergo such reactions in cells. Several experiments have been conducted that have suggested 2-aminofluorene be treated with care and with an overall awareness of the toxicity of this compound.
Penicillium verrucosum is a psychrophilic fungus which was discovered in Belgium and introduced by Dierckx in 1901. Six varieties of this species have been recognized based primarily on differences in colony colour: P. verrucosum var. album, P. verrucosum var. corymbiferum, P. verrucosum var. cyclopium, P. verrucosum var. ochraceum, P. verrucosum var. melanochlorum and P. verrucosum var. verrucosum. This fungus has important implications in food, specifically for grains and other cereal crops on which it grows. Its growth is carefully regulated in order to reduce food spoilage by this fungi and its toxic products. The genome of P. verrucosum has been sequenced and the gene clusters for the biosyntheses of its mycotoxins have been identified.
Nivalenol (NIV) is a mycotoxin of the trichothecene group. In nature it is mainly found in fungi of the Fusarium species. The Fusarium species belongs to the most prevalent mycotoxin producing fungi in the temperate regions of the northern hemisphere, therefore making them a considerable risk for the food crop production industry.