Microbial Analysis of Fungi Associated with Spoilage of Sweet Potato

Abstract

Sweet potatoes (Ipomoea batatas) are a vital staple crop, but their storage and shelf life are significantly compromised by fungal spoilage, leading to substantial economic losses. This study aims to isolate and identify fungal species associated with sweet potato spoilage, characterize their morphological and microscopic features, and discuss their implications for post-harvest management. Spoiled sweet potato samples were collected from local markets and storage facilities. Five distinct fungal species were isolated and identified: Aspergillus niger, Penicillium chrysogenum, Fusarium oxysporum, Rhizopus stolonifer, and Mucor spp. The identified fungi were characterized by their colony morphology and microscopic features. Aspergillus niger and Fusarium oxysporum were noted for their potential mycotoxin production, posing significant health risks. The study underscores the importance of proper storage conditions, sanitation, regular monitoring, and biocontrol measures to mitigate fungal contamination. These findings highlight the need for improved post-harvest management practices to reduce spoilage and economic losses associated with sweet potato storage.

RESULT AND DISCUSSION

RESULT

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From the spoiled sweet potato samples, five distinct fungal species were isolated and identified:Aspergillus niger Penicillium chrysogenum Fusarium oxysporum Rhizopus stolonifer Mucor spp.

Morphological and Microscopic Characteristics:

Aspergillus niger: Black conidia and rapid colony growth. Conidial heads with biseriate phialides were observed microscopically.Penicillium chrysogenum: Greenish-blue colonies with a powdery texture. Conidiophores with metulae and phialides forming brush-like clusters were noted microscopically.Fusarium oxysporum: Whitish-pink colonies with a cottony texture. Microconidia and macroconidia were observed microscopically.

Rhizopus stolonifer: Fast-growing colonies with black sporangia and white mycelium. Sporangia on sporangiophores with rhizoids were seen under the microscope.Mucor spp.: White, fluffy colonies. Non-septate hyphae with sporangia on simple sporangiophores were observed microscopically.

DISCUSSION

Analysis of Fungal Contamination

The identified fungal species are consistent with those commonly associated with sweet potato spoilage. The presence of Aspergillus niger and Fusarium oxysporum is particularly concerning due to their potential to produce mycotoxins, which can pose significant health risks.Rhizopus stolonifer and Mucor spp. are known for their rapid growth and ability to spread quickly, leading to extensive spoilage in stored sweet potatoes. Penicillium chrysogenum, while less aggressive, can still contribute to spoilage and reduce the quality and marketability of the tubers.

CONCLUSION

This study highlights the significant fungal species associated with sweet potato spoilage and underscores the importance of effective post-harvest management practices. By implementing recommended storage and handling practices, the risk of fungal contamination and associated economic losses can be minimized.

RECOMMENDATIONS

To mitigate fungal spoilage in sweet potatoes, it is essential to:

1. Enhance Storage Conditions: Ensure storage areas are cool, dry, and well-ventilated to inhibit fungal growth.

2. Implement Regular Sanitation: Clean and disinfect storage facilities and handling equipment frequently to prevent contamination.

3. Conduct Routine Monitoring: Regularly inspect stored sweet potatoes for early signs of fungal spoilage and utilize rapid testing for mycotoxins.

4. Adopt Biocontrol Measures: Use biological control agents and natural antifungal compounds to reduce reliance on chemical fungicides and improve safety.