Water activity influence on aflatoxin accumulation in corn

Area of Science:

• Agricultural Science
• Mycology
• Food Safety

Background:

• Aflatoxins are toxic secondary metabolites produced by Aspergillus species.
• Contamination of food crops like corn with aflatoxins poses a significant risk to human and animal health.
• Water activity is a critical environmental factor influencing fungal growth and mycotoxin production.

Purpose of the Study:

• To investigate the effect of different water activity levels on the production of four major aflatoxins (B1, B2, G1, G2) in corn.
• To determine the optimal water activity for aflatoxin accumulation by Aspergillus parasiticus in corn kernels.

Main Methods:

• Viable corn kernels were conditioned to specific water activity levels (0.87, 0.90, and 0.97).
• Kernels were inoculated with Aspergillus parasiticus and incubated at 30°C.
• Aflatoxin concentrations were quantified over time using thin-layer chromatography.

Main Results:

• Total aflatoxin accumulation varied significantly across the tested water activity levels.
• The highest accumulation of total aflatoxins was observed at a water activity of 0.90.
• Aflatoxin production was lower at water activities of 0.87 and 0.97 compared to 0.90.

Conclusions:

• Water activity is a key determinant of aflatoxin production in corn by Aspergillus parasiticus.
• A water activity of 0.90 appears to be most favorable for total aflatoxin accumulation under the studied conditions.
• These findings are crucial for developing strategies to control aflatoxin contamination in corn.