Experimental aflatoxin production in commercial yoghurt

Area of Science:

• Food Microbiology
• Mycotoxicology

Background:

• Aflatoxins are toxic secondary metabolites produced by certain fungi, posing a significant risk to food safety.
• Yoghurt, a widely consumed fermented dairy product, can potentially support fungal growth and mycotoxin production.

Purpose of the Study:

• To investigate the influence of varying incubation conditions on aflatoxin production in commercial yoghurt.
• To determine the optimal conditions for aflatoxin biosynthesis by Aspergillus parasiticus in a yoghurt matrix.

Main Methods:

• Commercial yoghurt was inoculated with Aspergillus parasiticus NRRL 2999.
• Incubation was performed under different temperature conditions (10°C, 15°C, 28°C) and container types (intact vs. damaged) to simulate varying microaerophilic levels.
• Fungal growth and aflatoxin concentrations (B and G) were quantified throughout the incubation period.

Main Results:

• Aflatoxin production was significantly higher at 28°C compared to 15°C.
• Microaerophilic conditions (damaged containers) resulted in increased aflatoxin levels compared to intact containers.
• No fungal growth or aflatoxin production was observed at 10°C.
• Fungal growth and aflatoxin concentration fluctuated during incubation rather than showing a consistent increase.
• The ratio of aflatoxin B to G varied with temperature, with a near 1:1 ratio at 28°C and a higher proportion of aflatoxin G at 15°C.

Conclusions:

• Temperature and oxygen availability are critical factors regulating aflatoxin biosynthesis in yoghurt.
• Specific incubation conditions can modulate the type and quantity of aflatoxins produced.
• Understanding these parameters is crucial for developing strategies to prevent mycotoxin contamination in fermented dairy products.