Mycotoxins are toxic (poisons) metabolites (wastes) produced by certain group of fungi. The word myco from Greek mykes or mukos meaning fungus and toxikon meaning ‘poison’. The fungi are saprophytic molds that grow on foodstuffs or animal feeds or on a range of crops. In other words, mycotoxns are secondary metabolite waste being chemical in nature that are produced by organisms of the fungus kingdom often referred to as molds. Hence, they are toxic chemical substances (mycotoxins) i.e. myco=fungus and toxic meaning poison. These fungi readily colonize crops. One mold species (fungus) may produce many different mycotoxins and of course, several species of molds may also produce one kind of mycotoxins.
Most fungi are aerobic in nature and are found almost everywhere in extreme small amount due to the minute size of their spores. Good environmental conditions such as favorable humidity temperature and presence of organic matter etc. promote the proliferation of fungal colonies and mycotoxin levels. The weakening effect of mycotoxins in the host encourages the utilization of this advantage for rapid growth of the fungi and increased level of mycotoxins.
The production of toxins depends on intrinsic and extrinsic environments. These toxins vary greatly in their severity of course depending on the susceptibility, metabolism and defense mechanisms of the organism infected. It was a documented fact that molds growing on foods have generally been considered to cause unaesthetic spoilage. It was also established that the fungal metabolites called mycotoxins were responsible for animal disease and death as well.
Mycotoxicoses: are the diseases caused by mycotoxins. These diseases have been responsible for major epidemics in man and animals.
MAJOR GROUPS OF MYCOTOXINS
1. Aflatoxins: are a type of mycotoxin produced by Aspergillus species of fungi such as Aspergillus flavus and Aspergillus parasiticus. Aflatoxins are of the following types, B1, B2, G1 and G2. Aflatoxin B1is the most toxic and is potent carcinogen having adverse health effect like liver cancer in most species of animals
Origin of Aflatoxins: Aflatoxins are mostly associated with crops/commodities produced in the tropics and subtropics like cotton, peanuts, spices, maize, melon, groundnuts cocoa seeds etc.
2. Ochratoxins are examples of mycotoxins that range in 3 forms namely A,B, and C.
Origin; mold producing fungus is penicillium and Aspergillus spp.
Ochratoxin A is a chlorinated form
Ochrotoxin B is a non-chlorinated form of ochratoxin A
Ochrotoxin C (OTC) is an ethyl ester form of ochtratoxin A
Aspergillus ochraceus is a major contaminant of a wide range of commodities including beverages like beer and wine.
Aspergillus carbonarius is a mold species that release a toxin in vine fruits. This toxin tends to contaminate juice during its preparation method.
Effect of Ochratoxin A (OTA). It is carcinogenic and nephrotoxic and has been linked with tumor and urinary tract infections
3. CITRININ: is another toxin isolated from penicillium citrinum.
The toxin is also present in many other penicillium and Aspergillus species.
Effect of citrinin: the toxin is linked with yellow rice disease and nephrotoxic in many farm animals in Japan.
This toxin affect many crops like wheat, rice, corn, barley, oat, ryre etc.
4. Ergot Alkaloids: are compounds produce of a toxic mixture of alkaloids.
Ingestion of the toxin from infection cereals, especially in bread made from contaminated flour, cause ergotism. Ergotism was formerly known as St Anthony’s fire in humans. The toxins affect the central nervous system and supply of blood to extremities of the body.
Ergot alkaloids have beenused significantly in pharmaceuticals
5. Patulin: is another toxin produced by patulin expansium, Aspergillus sp, penicillium and paecilomyces fungal species.
Effects: P expansum is associated with a range of moldy fruits and vegetables especially rotten apple and figs. Patulin is not carcinogenic and does not destroy immune system in animals.
6. Fusarium: Toxins produced by over 50 species of fusanium. The toxins affect grains of young cereal plants such as wheat, maize, rice etc. Effects: Toxins affect the nervous systems of horses. It may also cause cancer in rodents.
7. Mushrooms: Mushrooms constitute a source of assortment of fungal poisons which cause many health problems in animals and humans. Examples of mushroom producing poisons include Amnita Rhalloides. It is toxic having the potential to cause almost 90% of all mushroom fatalities. Other example of mycotoxin groups in mushrooms are orellanine, monomethyhydrazine, disulfiram-like, hallucinogenic indoles, muscarinic, isoxazole and gastrointestinal GI-specific irritants.
8. Indo environment: Buildings from major source of mycotoxins. People living or working in areas of high mold density suffer from the adverse effects of mycotoxins. Molds growing in buildings contain high amount of mycotoxins. These mycotin molds have been associated with allergins and respiratory infections.
MYCOTOXINS IN FOOD
Mycotoxins are present in foods as a result of fungal infection of crops. Humans eat directly the mycotoxin or indirectly being used as animal feed. In 2004, in Kenya 125 people died and 200 people were treated after eating aflatoxin contaminated maize. Spices are susceptible substrate’s for growth of mycotoxigenic fungi and mycotoxin products, e.g. dried ginger, black pepper are mostly found to be contaminated spices.
Mycotoxins in animal folder, especially silage, can decrease performance of farm animals which potentially kill them.
IN DIETARY SUPPLEMENTS
Contaminant of medicinal plants with mycotoxins can contribute adverse human health problem and therefore represent a special hazard.
Mycotoxins have the potential for acute and chronic health effects through ingestion, skin contact, and inhalation. These mycotoxins can enter blood and lymphatic system, thereb inhibiting protein synthesis and damaging macrophases acute liver damage, liver cirrhosis, induction of tumors and teratogenic and other genetic effects.
Acute toxicity of aflatoin causing hepatitis, and liver cancer
Ochratoxin: Causes nephritis (kidney inflammation). Death rate may be high as a result of kidney failure due to ochratoxin. The toxic effect of mycotoxins on animals and humans is enormous. The severity which depends on the toxicity of the mycotoxin, the extent of exposure, age and nutritional status.
Molds are ubiquitous and universally found where environmental conditions are conducive to their growth. Aflatoxin in humans are acutely toxic, immunosuppressive, mutagenic, tetragenic and carcinogenic compounds. In poultry production, feed is the key vector for introducing mycotoxin into flocks. Mycotoxin xposure is more common where poor methods of food handling and storage are common. The contamination of food and feed by mycotoxin fishery products by phycotoxin and edible plant species has been documented.
IMPACT OF AFLATOXIN ON CHILDREN
Aflatoin causes acute poisoning with fatal result in children. Chronic exposure to aflatoxin is associated with stunting and immune suppression. Studies carried out in Benin and Togo have shown that elevated levels of aflatoxin in the blood are associated with stunting and underweight in children (Gong etal; 2002)
ESTABLISHMENT OF MINISTERIAL TECHNICAL COMMITTEE ON MYCOTOXIN
Owing to a wide range impact on health, trade, agriculture, market limitation and food, prevention and control of aflatoxin requires a comprehensive integrated multidimensional approach, thus, in response to the adverse effect and threats of aflatoxins to consumers of agricultural products and trade limitation, the Federal Government and development partners identifies the need to set up an interministerial mycotoxin technical committee with the sole aim of creating aflatoxin awareness in food and other products and adapt a wide scale approach towards the prevention and control of aflatoxin Prevalence of mycotoxins (afflatoxin) is promoted by droughts, pests, delayed harvest, insufficient drying conditios and poor post-harvest handling. These factors are all common in Nigeria. Poor people are particularly at risk because of their dependence on staple food crops. Aflatoxin contaminated food cannot be detected visually or by smell or taste, making it difficult for consumers to avoid eating contaminated food. Therefore exposure of high levels of aflatoxins through consumption of contaminated food leads to death (Shepherd, 2008).
OBJECTIVES OF THE COMMITTEE
• The technical committee is to harness collective experience and knowledge of the stakeholders to generate information to develop a strategy for the control of aflatoxin nationwide.
• To embark on a strong campaign that would create significant contributions to reduce the irreversible harm of aflatoxin among children
• To create awareness of the harmful effects of aflatoxin contamination and impacts among consumers and farmers, extension workers; professionals and decision makers
• To create awareness for all stakeholders as well as comprehensive capacity value chain.
• To fashion out a way of making our consumable crops and export products free.
• To establish technologies such as post-harvest drying techniques that can be adapted for use in different contexts.
The committee was inaugurated with the view to fostering a partnership initiative that seeks to Marshall all efforts across Nigeria and coordinating all plans to effectively create needed awareness for the prevention and control of aflatoxins in Nigeria.
Membership of the committee cuts across the different technical departments of FMARD and other stakeholders and Mrs.Maimuna A Habib, PhD was appointed the coordinator of the committee. The committee secretariat is domiciled in Nigeria Agricultural Quarantine Service (NAQS).
MYCOTOXICOSES: are the diseases caused by mycotoxins. Death, identifiable diseases, health problems, weakened immune systems, act as allergins and irritants. Mycotoxins are harmful to microorganism such as bacteria and fungi. Mycotoxins can be acutely or chronically toxic or both depending on the kind of toxin and the dose.
i. In Animals, acute diseases including liver and kidney damage
ii. Attack on centra nervous system
iii. Skin disorder which may be necrotic lesion and photosensitivity
iv. Hormonal effects including abortion in cattle, swollen genitals in pigs, feed refusal and failure to thrive.
v. Carcinogenic effect
vi. Acute mycotoxicoses
vii. Ergotism causes contusion in blood vessels leading to hands and feet ergotism in extreme cases causes necrosis (death of cells).
viii. Alimentary toxic aleukia. ATA causes death of people in USSR. ATA causes fever, bleeding from the skin, nose, throat and gum, necrosis and suppression of immune system. The toxin responsible for ATA was the Trichothecane toxin known as T-2. It was produced by the growth of Fusarium species when grains are allowed to remain in the field unharvested. Trichothecane maybe involved in the high incidence of oesophagal cancer in South Africa.
ix. Acute Cardiac beriberi: is another human mytoxicoses of significance. The disease is characterized by difficulties in breathing, nausea and vomiting, severe pain and distress. Respiratory and death may occur. Acute beriberi is caused by citreoviridin, a mycotoxin produced by penicillium citreonigrum
x. Onyalai: is an acute disease characterized by hemorrhaging lesions in the mouth. The mycotoxin is produced by molds that infect millets.
xi. Aflatoxins were discovered in 1960 following the death of 100,000 young turkeys in England and high incidences of liver disease in ducklings in Kenya.
Effects of Aflatoxins: Aflatoxins have acute and chronic toxicity in animals causing death.