Mycotoxins Detection and Fungal Contamination in Black and Green Tea by HPLC-Based Method

Area of Science:

• Food Science
• Mycology
• Analytical Chemistry

Background:

• Mycotoxin contamination in tea poses a significant food safety concern.
• Aflatoxins (AF) and Ochratoxin A (OTA) are common mycotoxins found in agricultural products.
• Tea, a globally consumed beverage, requires rigorous quality control to ensure consumer safety.

Purpose of the Study:

• To assess the levels of fungal contamination, total aflatoxins (AF), and ochratoxin A (OTA) in tea samples.
• To identify predominant fungal species associated with tea contamination.
• To evaluate compliance with regulatory limits for AF and OTA in tea.

Main Methods:

• 60 tea samples were analyzed for fungal contamination and mycotoxin content.
• Immunoaffinity columns were used for sample extraction and cleanup.
• High-performance liquid chromatography with fluorescence detection (HPLC-FD) quantified AF and OTA.
• Fungal cultures were used for identification of contaminating species.

Main Results:

• 40% of tea samples showed contamination with aflatoxins (AF), but none exceeded the acceptable limit (≥10 μg/kg).
• All tea samples were contaminated with ochratoxin A (OTA); 6.6% of black tea and 6.7% of green tea exceeded the 10 μg·kg⁻¹ limit.
• Mean OTA concentration was higher in black tea than in green tea.
• Aspergillus niger was the predominant fungus isolated from both black and green tea samples.

Conclusions:

• Widespread OTA contamination in tea necessitates attention, despite generally acceptable AF levels.
• Specific tea types, like black tea, may exhibit higher OTA levels.
• Regular monitoring of mycotoxins throughout the tea production process is crucial for quality improvement and consumer protection.