Q.15 Aflatoxins are produced by:
- Aspergillus flavus
- Penicillium rubrum
- Cordyceps purpurea
- Claviceps purpurea
Aspergillus flavus produces aflatoxins, potent hepatocarcinogenic mycotoxins contaminating grains, nuts, and feeds under warm, humid conditions.
Question Breakdown
Aflatoxins (B1, B2, G1, G2) are polyketide toxins causing acute liver failure and chronic cancer. This mycology question distinguishes aflatoxin producers (Aspergillus section Flavi) from other fungal toxin producers.
Option Analysis
Aspergillus flavus
Correct. Primary aflatoxin producer on maize, peanuts, cottonseed. Sclerotia-forming strains produce AFB1/AFB2; L-strain (large sclerotia) most toxigenic. Global food safety concern.
Penicillium rubrum
Incorrect. No aflatoxin production. Penicillium spp. produce ochratoxin, patulin, citrinin (e.g., P. verrucosum). Red-spored saprophyte on grains.
Cordyceps purpurea
Incorrect. Entomopathogenic ascomycete (purple Cordyceps). Parasitizes insect larvae; no plant mycotoxins or aflatoxins. Medicinal (cordycepin).
Claviceps purpurea
Incorrect. Ergot fungus produces ergot alkaloids (ergotamine, LSD precursors) causing ergotism. Rye sclerotia (ergots); no aflatoxins.
Correct Answer: Aspergillus flavus – Dominant aflatoxin producer.
Aflatoxins produced by Aspergillus flavus pose severe food safety risks, causing hepatotoxicity and cancer via contaminated staples. This mycotoxin dominates your microbiology studies on fungal pathogenesis.
Aflatoxin Biosynthesis & Impact
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Cluster: 30+ genes (aflR regulator, polyketide synthase).
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Pathway: Acetate → Norsolorinic acid → Versicolorin → AFB1 (most potent).
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Conditions: >25°C, >85% RH, drought-stressed crops.
Public Health Crisis
AFB1 IARC Group 1 carcinogen; 4.5 billion exposed annually. Indian peanut butter recalls frequent. Limits: 20 ppb (US), 15 µg/kg (EU).
Fungus Toxin Produced Crop Targets Aspergillus flavus Aflatoxins B1/B2 Maize, peanuts, cotton Penicillium rubrum Ochratoxin, patulin Stored grains Cordyceps purpurea None (insect parasite) Insects Claviceps purpurea Ergot alkaloids Rye ergot Prevention: Biocontrol (Atoxigenic A. flavus strains), storage <13% moisture.
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