Improved method of screening for aflatoxin with a coconut agar medium

Area of Science:

• Mycology
• Food Safety
• Analytical Chemistry

Background:

• Aspergillus flavus and Aspergillus parasiticus are significant sources of aflatoxins, potent carcinogens found in various food products.
• Accurate and efficient detection methods are crucial for ensuring food safety and preventing mycotoxin contamination.
• Current detection methods can be complex and time-consuming, necessitating simpler screening tools.

Purpose of the Study:

• To develop and validate a novel screening method for detecting aflatoxin production by Aspergillus species.
• To evaluate the efficacy of coconut extract agar as a growth medium for identifying aflatoxigenic fungi.
• To assess the suitability of readily available shredded coconut for use in this diagnostic test.

Main Methods:

• Nine Aspergillus flavus and Aspergillus parasiticus isolates were cultured on coconut extract agar medium.
• Aflatoxin production was initially screened by observing blue fluorescence under long-wave UV light (365 nm) on the reverse of colonies after 2-5 days.
• Positive results were confirmed using chemical analysis, and various types of shredded coconut were tested for medium suitability.

Main Results:

• The coconut extract agar medium successfully supported the growth of Aspergillus isolates.
• Blue fluorescence indicative of aflatoxin production was observed under UV light in producing colonies.
• Several commercially available shredded coconut types proved satisfactory for medium preparation, requiring no additives.

Conclusions:

• Coconut extract agar is a viable and effective medium for the presumptive detection of aflatoxin-producing Aspergillus species.
• The UV fluorescence method provides a rapid and simple screening tool for identifying toxigenic fungi in food matrices.
• This method offers a practical approach for routine testing and monitoring of aflatoxin contamination in food products.