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Aspergillus growth and aflatoxin production on black pepper
Abstract:
Black peppercorns supported the growth of Aspergillus parasiticus (flavus) NRRL 3145. Incubation at 28 C and RH of 85% for 30 days resulted in profuse conidial production on the reticulate ridges of the peppercorns. An SEM study of these ridges showed that they were cortical eruptions, and the particulate matter present favored mycelial establishment. Hyphal anastamoses were commonly observed. Following this incubation the inoculated peppercorns were stored in the dark at room temperature and ambient humidity for 15 days. Aflatoxin was detected on minicolumn. Aflatoxin B1 was produced at levels of 60 micrograms/kg with traces of aflatoxin B2, G1 and G2. Quantitative estimation was based on a visual comparison with standards by thin-layer chromatography.
Insights
Black peppercorns can support the growth of Aspergillus parasiticus, a fungus that produces harmful aflatoxins. This study found aflatoxin B1 on inoculated peppercorns, highlighting potential food safety risks.
Area of Science:
- Food Microbiology
- Mycology
- Plant Pathology
Background:
- Black peppercorns are a globally traded commodity.
- Aspergillus parasiticus (flavus) is a known producer of toxic aflatoxins.
- Fungal growth and mycotoxin production on spices are significant food safety concerns.
Purpose of the Study:
- To investigate the potential of black peppercorns to support Aspergillus parasiticus growth.
- To determine if aflatoxin production occurs on inoculated black peppercorns.
- To characterize the surface morphology of peppercorns influencing fungal colonization.
Main Methods:
- Incubation of Aspergillus parasiticus NRRL 3145 on black peppercorns at 28°C and 85% RH for 30 days.
- Scanning Electron Microscopy (SEM) to examine peppercorn surface structures.
- Post-incubation storage under ambient conditions for 15 days.
- Aflatoxin detection and quantification using minicolumn assays and thin-layer chromatography (TLC).
Main Results:
- Profuse conidial production of Aspergillus parasiticus was observed on the reticulate ridges of peppercorns.
- SEM revealed these ridges as cortical eruptions, facilitating mycelial establishment.
- Aflatoxin B1 (60 µg/kg) was detected, along with traces of B2, G1, and G2.
- Hyphal anastamoses were commonly observed, indicating fungal network formation.
Conclusions:
- Black peppercorns provide a suitable substrate for Aspergillus parasiticus growth and conidiation.
- The surface morphology of peppercorns aids in fungal colonization and subsequent aflatoxin production.
- The presence of aflatoxins on inoculated peppercorns indicates a potential food safety risk associated with contaminated spices.