What are Mycotoxins?
Mycotoxins are toxic secondary metabolites produced by fungi such as Aspergillus, Penicillium, and Fusarium, commonly found on food and feed products like grains, nuts, fruits, and spices. Even at low concentrations, these toxins pose significant health risks including:
- Carcinogenic
- Mutagenic
- Teratogenic
- Immunosuppressive
- Hepatotoxic
Environmental conditions such as high humidity and temperature during storage and cultivation increase the risk of contamination. As a result, food safety authorities globally emphasize rigorous monitoring, agricultural best practices, and regulatory limits to minimize health and economic impacts.
Characteristics of Mycotoxins
- Source: Mycotoxins are harmful substances that are created by specific molds that develop on food and plants.
- Chemical Properties: They are secondary metabolites with a wide range of chemical structures and low molecular weights.
- Stability: Mycotoxins are heat stable and resistant to most food processing techniques.
- Toxicity: They are extremely poisonous, causing both immediate and long-term health consequences in people and animals.
- Specificity: Particular mycotoxin kinds are produced by particular fungi.
- Occurrence: They have the potential to infect food either before the harvest or during storage in humid environments.
- Identification: Because of poor visibility, sophisticated methods like HPLC or ELISA are necessary for detection.
- Regulatory Restrictions: Mycotoxin concentrations in food and feed are subject to legal restrictions in many nations.
Routes of Mycotoxin Exposure
The route of infection (or exposure) of mycotoxins refers to how these poisonous secondary metabolites generated by fungi enter and impact an organism. Mycotoxins are not infectious in the conventional microbiological sense (like bacteria or viruses); rather, they enter the body and induce toxicity.
The main routes of exposure are listed below:
- Ingestion (Oral Route): Most Common Mycotoxin exposure’s primary route result from eating infected: Grains (wheat, corn, and rice), nuts (peanuts, almonds), Herbs milk, eggs, and meat from animals that ate contaminated feed. Examples: corn or peanuts containing aflatoxins. Coffee or grains containing ochratoxin A. Maize contains fumonisins.
- Inhalation: Grain handlers, agricultural laborers, or individuals who are exposed to moldy settings (such as humid structures) inhale dust or airborne spores that carry mycotoxins. Spores of Aspergillus, Penicillium, and Stachybotrys may include mycotoxins that can be aerosolized.
- Skin Contact: Direct contact with the skin Less prevalent, but still possible when handling infected items. Mycotoxins are able to enter the skin, especially when the barrier is breached. More applicable in professional contexts (grain handlers, farmers). May induce systemic toxicity or local irritation.
- Transplacental Transfer: Transplacental (in utero) if the mother is exposed; some mycotoxins (such as ochratoxins and aflatoxins) cross the placenta and harm the fetus, potentially resulting in birth abnormalities or developmental challenges.
Major Types of Mycotoxins
1. Aflatoxins
- Aspergillus flavus, Aspergillus parasiticus, and some Penicillium species produce it.
- Researchers find it in a variety of mold-contaminated foods. Peanuts, rice, and other foods are examples.
- There are two primary forms of toxin: B1 and G1, which emit blue and green fluorescence when exposed to UV radiation.
- The other forms of aflatoxins, B2, G2, M1, M2, and P1, are generated from B1 and G1.
- Among them, B1 is the most harmful.
- Aflatoxin binds to chromosomal DNA after swallowing. It also induces point and frameshift mutations.
- They produce liver cancer by causing mutation.
- Aflatoxin is hazardous to a wide range of animals, including cats, Chicken, cows, people, and so on.
2. Patulin
- A wide variety of fungi produce it.
- Penicillium expansum, Penicillium patulum, and Penicillium melini are examples.
- Among the fungus isolated are Penicillium equinum, Aspergillus clavatus, Aspergillus terreus, and others.
- Researchers obtained it from numerous mold-contaminated items, such as bread, sausages, and fruits.
- It is a white, crystalline substance.
- It is susceptible to SO2 and alkali, yet resistant to acid.
- Patulin interacts with the NH2 and SH functional groups of biomolecules, causing chromosomal abnormalities.
- It has an impact on a wide range of animals and plants; Bacterial cells, such as coli and Staphylococcus Aureus are examples of prokaryotic creatures.
- As a result, it was first classified as an antibiotic.
- Patulin-induced tissue damage includes edema of the brain, lung, and blood capillary, as well as spleen and kidney damage.
3. Penicillic acid
- Penicillium roqueforti, Penicillium Cyclopium, Penicillium morteneii, Aspergillus flavus, and Aspergillus ochraceus produce it.
- Many molds that contaminate food, such as tobacco, isolate it.
- Penicillic acid binds to biomolecule’s -SH and -NH2 groups, resulting in the formation of Covalent bond.
- It is carcinogenic and has a diverse effect on animals, including rats.
4. Citrinin
- Penicillium citrinum, Penicillium viridicatum, and other species make it.
- It is distinct from many mold-contaminated foods, such as polished rice, Bread, meat, and meat products.
- It is deadly to a broad range of animals.
5. Ochratoxin
- At least seven structurally related ochratoxins exist. The most prevalent and harmful form is type A.
- Many Aspergillus and Penicillium species, including Ochraceus, A. alliaceus, A. mellis, P. viridicatum, and P. cycloplum.
- Like other mycotoxins, it is heat stable and unaffected by cooking.
- When consumed, ochratoxin promotes cell division, leading to cancer of the Kidney. Peptide Hormones (Basidiomycetes): Basidiomycetes, a family of fungus that contains mushrooms, create peptide hormones. These hormones control a variety of biological activities, including growth, development, and responses to environmental inputs.
6. Sterigmatocystin
- Aspergillus versicolor, Aspergillus nidulus, Aspergillus regulosus, and other species produce it.
- It induces liver cancer by inhibiting DNA synthesis.
Prevention Strategies for Mycotoxin Contamination
Integrated control methods are necessary to minimize risk:
Pre-Harvest
- Crop rotation and resistant varieties.
- Proper timing of planting and harvesting.
- Pest and weed control.
Post-Harvest
- Immediate drying to safe moisture levels.
- Dry, cool storage conditions.
- Routine inspection and cleaning.
- Removal of visibly moldy grains.
- Use of biological control agents or natural antifungals.
- Application of mycotoxin binders in animal feeds.
Mycohormones
Fungi produce mycohormones, which are hormone-like chemicals that control their growth, development, and interactions with plants.
Types of mycohormones
- Sirenin (Allomyces): Allomyces produces Sirenin, a pheromone that is a water mold. It acts as a mating hormone attracting other cells or organisms for sexual reproduction. Sirenin participates in the mating process of Allomyces. This process causes the fusion of gametes during sexual reproduction.
- Sterols (Achlya): Sterols are lipids that it contains chemicals like as ergosterol. Achlya, a Water mold is well known for its sterol production. Ergosterol is the fungal counterpart of cholesterol and an important component of the fungal cell membrane, contributing to its structural integrity and function.
- Trisporic Acid (Ascomycetes): Trisporic acid is a sexual hormone or pheromone secreted by some types of Ascomycetes fungi. It plays an important part in the mating process by regulating sexual development and the fusion of compatible mating forms.
- Peptide Hormones (Basidiomycetes): Basidiomycetes, a family of fungus that contains mushrooms, create peptide hormones. These hormones control a variety of biological activities, including growth, development, and responses to environmental inputs.
Conclusion
Mycotoxins and mycohormones represent two critical yet contrasting aspects of fungal biology. While mycotoxins threaten food safety and public health, mycohormones contribute to the ecological roles and life cycles of fungi. Understanding their nature, effects, and prevention strategies is essential for sustainable agriculture, public health, and safe food systems.
