MYCOTOXINS ARE PRODUCED BY FUNGI

MYCOTOXINS ARE PRODUCED BY FUNGI

AGUS SELAMET DUNIAJI*)

Mycotoxins are poisons or toxins produced by toxigenic fungi that live and grow on food ingredients and products, both during food in the fields and during storage. This toxin is a secondary metabolite produced by the fungus as a way to defend itself, and then excreted out. Mycotoxins affect agricultural economies in various countries, disrupt trade, reduce livestock production and affect human health. Mycotoxins are very dangerous because they are mutagenic, teratogenicity, and carcinogenic

Mycotoxins

Mycotoxins come from two words, mukes which means fungus (Greek) and toxicum which refers to poison (Latin). Mycotoxins are a term used to refer to toxins produced by fungi. More complete, mycotoxins are defined as natural products with low molecular weights produced as secondary metabolites of filamentous fungi and can cause disease and even death in humans, animals, plants, and other microorganisms.

Mycotoxins are toxins produced by toxigenic fungi that live and grow in food, both during food in the fields and during storage. This toxin is a secondary metabolite produced by the fungus as a way to defend itself, and then excreted out. Because this toxin is not a protein, heat treatment cannot inhibit its growth in food.

Mycotoxins are very dangerous because they are mutagenic, terratogenic, and carcinogenic. Some examples of important mycotoxins in foods that have been studied to date, namely aflatoxin, patulin, ochratoxin, fumonisin, and deokynivalenol (DON). Examples of food that live on mycotoxins are corn, coffee, and cereals. Although the mycotoxins produced by the fungus are dangerous, there are several types of fungus that are harmless and function for food processing.

Mycotoxins are invisible, odorless and cannot be detected by smell or taste, but can significantly reduce livestock production performance. Mycotoxins affect agricultural economies in various countries, disrupt trade, reduce livestock production and affect human health.

Types of Mycotoxins

Mycotoxins are toxic secondary metabolites produced by various types of pathogenic fungi. There are eight main types of mycotoxins that often harm humans, namely aflatoxin, ochratoxin, fumonisin, trichothecene, zearalenone, citrinin, patulin and ergot alkaloids.

Aflatoxin comes from the abbreviation Aspergillus flavus toxin. This toxin was first known to originate from the fungus Aspergillus flavus which was isolated in 1960. Mycotoxins are carcinogenic, hepatatoxic, and mutagenic so that they are of concern to the world health body (WHO) and are categorized as carcinogenic goal 1A. In addition, aflatoxin is also immunosuppressive which can reduce the immune system. In Indonesia, aflatoxin is a mycotoxin that is often found in agricultural products and processed products.

Oxytocin is a mycotoxin which is a group of 7 isocumarin derivatives that are linked through amide bonds with the amino group of L-b phenylalanine. At present, there are at least 3 types of oxytocin, namely oxytocin A (OA), oxytocin B (OB), and oxytocin C (OC), but the most widely studied is ochratoxin A because it is the most toxic among others.

Fumonisins are toxins produced by Fusarium moniliforme. Fumonisins are diester compounds with several polyhydric alcohols and tricarboxylic acids. Fumonisins also contain a major part of amines and are soluble in water and thermostable. The molecular formulas of Fumonisins B1 and B2 are C34H59O15 and C34H59O14, which distinguishes only the hydroxy groups on C-10 atoms. Based on the chemical structure and its producing fungus, trichothecene grouped into 4 types, namely A (functional groups other than ketones at position C8), B (carbonyl groups at C8), C (epoxides at C7.8 or C9.10) and D (systems microcyclic rings between C4 and C15 with 2 ester bonds). There are 37 types of natural sesquiterpenoids belonging to the trichothecene group and are usually produced by Fusarium, Stachybotrys, Myrothecium, Trichodemza, and Cephalosporium. This toxin is found in various cereals and grains in America, Asia and Europe. This toxin is stable and resistant to heating and food processing by autoclave. In addition, if it enters human digestion, the toxin will be difficult to hydrolyze because it is stable at acidic and neutral pH

Zearalenon was first isolated in 1962. This fungus grows at an optimum temperature of 20 - 250 C and humidity of 40 - 60 percent. Zearalenon is quite stable and resistant to high temperatures. Until now there are at least 6 kinds of zearalenon derivatives, among them α-zearalenol which has 3 times the estrogenic activity than the parent compound. Other derivative compounds are 6,8-dihydroxyzearalenone, 8-hydroxyzearalenone, 3-hydroxyzearalenone, 7-dehydrozearalenon, and 5- formylzearalenon.

Citrinin was first isolated from Penicillium citrinum Thom in 1931. Mycotoxins were found as natural contaminants in corn, rice, wheat, barley, and rye. Citrinin is taken from the name of the microorganism that produces this mycotoxin, namely Penicillium citrinum. Citrinin was first isolated from contaminated wheat, rice and corn (Richard, 2016). Citrinin is a secondary metabolite of P. citrinum and citrinin is usually found together with okratoxin A because usually microorganisms that produce octratoxin A will also produce citrinin. The characteristics of citrinin are optically active, yellow crystalline, and thermostable dissolved in 95% ethanol or n-hexane (Park et al., 2000). The molecular formula of citrinin is C13H14O5.

Patulin is a toxin produced by several species from the Penicillium, Aspergillus, and Byssochlamys groups. Patulin (PAT) was discovered in 1943 in connection with P. griseofulvum and P. expansum. The molecule was first studied as a potential antibiotic, but subsequent studies showed its toxicological properties. It is toxic to almost all living things, from bacteria, higher plants, animals, to mammalian cells. Patulin has properties that are thought to be similar to carcinogenic compounds that are of concern to the public. The characteristics of patulin are colorless, crystalline compounds, and able to dissolve in water and organic polar solutions. The structure of patulin is highly reactive unsaturated lactone, C7H6O4 or 4-hydroxy-4H-furo [3,2-c] pyran-2 (6H) -one. This toxin can also bind sulfhydryl groups such as cysteine, thioglycolic acid, and glutathione

Ergot alkaloids are produced by various types of fungi from the Clavicipitaceae group. contamination of these compounds in food can cause epidemic poisoning of ergot (ergotism) which can be found in two forms, namely the form of gangrene (gangrenous) and convulsions (convulsive).

Fungus and Mycotoxin Contamination

Aflatoxin is a toxin produced by several types of fungi produced in hot and humid environments. This type of fungus is from the Aspergillus sp. Group, and the toxin is produced when they succeed in infecting a commodity, growing and developing, and subsequently finding suitable conditions for them to produce the toxin. Species that are identified to produce aflatoxin in particular are A. flavus, A. parasiticus, and A. nomius. One such species, namely A. flavus, is a microorganism that is often found in soil and air in almost all parts of the earth. A. flavus is also often found in storage of commodities or materials such as wheat, rice, coffee beans, and flour. A. flavus as the main producer of aflatoxin generally only produces aflatoxin B1 and B2 (AFB1 and AFB2) while A. parasiticus produces AFB1, AFB2, AFG1, and AFG2. A. flavus and A. parasiticus grow in a far temperature range, which ranges from 10-120C to 42-430C with an optimum temperature of 320-330C and an optimum pH of 6. Among these four aflatoxin AFB1 has the highest toxic effect.

Ochratoxin is produced by fungi from the genus Aspergillus, Fusarium, and Penicillium and is found in a variety of foods, ranging from cereals, pigs, chickens, coffee, beer, wine, grape juice, and milk. Oxytocin A is the most toxic and most commonly found in nature. OA can be found widely in agricultural commodities such as wheat, coffee and grains both before harvest, at harvest time, transportation (transportation) and in storage Fumonisins are produced by certain Fusarium spp. including F. verticillioides (Sacc.) Nirenberg, F. proliferatum (Matsushima) Nirenberg and F. nygamai Burgess and Trimboli. The dominant fungus was isolated from maize contaminated with fumonisin, related to the outbreak of Equine Leukoencephalomalacia (ELEM) in South Africa in 1970 and Lung Porcine Edema (PPE) in Iowa, Illinois, and Georgia in 1989, was F. Verticillioides. Fumonisin is a type of fusarium toxin, which is produced by the fungus Fusarium sp, especially F. moniliforme, and F. proliferatum. This Fusarium fungus grows and is spread in various countries in the world, especially in tropical and sub-tropical countries. This toxin is dangerous because it can become a contaminant in agricultural commodities. Agricultural commodities that are often contaminated with this fungus are corn, wheat, sorghum, and various other agricultural products. This type of toxin is stable and resistant to various corn processing processes so that it can cause the spread of toxins in bran, sprouts, and corn flour. Fumonisin concentration can decrease in the process of making corn starch by wet grinding because this compound is water-soluble

Trichothecenes belong to the main class of mycotoxins produced by a number of fungi from the order Hypocreales, including those from the genus Fusarium, Myrothecium, Verticimonosporium, Stachybotrys, Trichoderma, Trichodecium, Trichothecium, and Cindra. Trichotene is a mycotoxin produced by the fungus Fusarium spp. which is commonly found in grains, such as wheat, oats, and corn. The toxin has a heavy influence on human and animal health, which is causing immunosuppressive. According to Bennet et al. (2003) that trichotene is usually found as contaminants in food and feed, and if consumed, mycotoxins will cause bleeding in digestion and vomiting, if there is direct contact it will cause dermatitis

Zearalenon is an estrogenic toxin produced by the fungus Fusarium graminearum, F.tricinctum, and F. moniliforme. Zearalenone (ZEA) is a mycotoxin that is produced as a secondary metabolite by several species of fungi in the Fusarium group - specifically F. culmorum, F. roseum, F. graminearum. These three types can be found all over the world and can attack commodities both pre-harvest and post-harvest. Commodities that can be contaminated with ZEA are usually rice, corn, barley, wheat, and several other types of agricultural products that can later contaminate human food and animal feed. The molecular formula of ZEA is C18H22O5.

The commodities that are heavily tainted with zearalenon are corn, wheat, soybeans, rice, and other cereals. Zearalenone is a mycotoxin which is also produced by Fusarium spp. Besides trichotene and zeara lenon, Fusarium spp. Also produces fumonisin toxin. Zearalenone can be found as a contaminant of cereal plants (grains) throughout the world

Citrinin is also known to be produced by various Monascus species and this is of particular concern to the Asian community who use Monascus as a source of additional food substances. Monascus is widely used to extract pigments (especially red) and in its growth process, the formation of the citrinin toxin by Monascus needs to be prevented.

Citrinin is a type of mycoxin produced by the fungus Penicilium citrinum. This fungus species can contaminate various kinds of food ingredients, especially grains that have been damaged, such as wrinkles, hollow seeds, and peeling so they are easily contaminated with fungus spores. Wang et al. (2004) states that Citrinin is a mycotoxin that is nephrotoxic and hepatoxic, because it causes damage to the function and structure of the kidneys as well as function and metabolic changes in the liver. Citrinin is a type of mycoxin produced by the fungus Penicilium citrinum. This fungus species can contaminate various kinds of food ingredients, especially grains that have been damaged, such as wrinkles, hollow seeds, and peeling so that it is easily contaminated with fungus spores

Patulin is produced by Penicillium, Aspergillus, Byssochlamys, and the most important species in producing this compound is Penicillium expansum. This toxin causes contamination in fruits, vegetables, cereals, and especially apples and processed apple products so certain treatments are needed to remove patulin from plant tissues. An example is washing apples with ozone to control patulin pollution. In addition, alcoholic fermentation of fruit juices is known to destroy patulin.

Patulin can be found in a variety of food products and raw materials, but apples and byproducts are the biggest concern regarding PAT accumulation: the frequency of contamination in resources and other food products is much lower than in apple processing.  PAT has been reported to be mutagenic and causes neurotoxic, immunotoxic, genotoxic and gastrointestinal effects in rats; therefore, there are some concerns that similar effects can occur in humans as a consequence of long-term consumption of contaminated food or drinks.

Ergot alkaloids are produced by various types of fungi, but the main group is Clavicipitaceae. Formerly contamination of this compound in food can cause epidemic poisoning of ergot (ergotism) which can be found in two forms, namely the form of gangrene (gangrenous) and convulsions (convulsive). In livestock, ergot alkaloid can cause tall fescue toxicities which is characterized by a decrease in milk production, loss of body weight, and decreased fertility. Mechanical cereal cleansing does not fully protect against contamination of this compound because some types of wheat are still attacked by ergot because the seed varieties used are not resistant to Claviceps purpurea, an alkaloid-producing ergot.

*). The author is a teaching staff at the Food Science and Technology Study Program Faculty of Agricultural Technology, Udayana University, Bali