Research – Effects of oilseed substrates (ground nyjer and flax seeds) on the growth and Ochratoxin A production by Aspergillus carbonarius

Wiley Online

kswfoodworld

Image CDC

Aspergillus carbonarius is one of the major Ochratoxin A (OTA) producing fungus. Nyjer and flax seeds are important oilseeds that are used for both human and animal consumption, but they are highly susceptible to fungal growth and mycotoxin contamination. The objectives of this study were to determine the growth and OTA production by A. carbonarius on ground nyjer and flax seeds with water activity levels ranging from 0.82 to 0.98 aw at three incubation temperatures (20, 30, 37°C). It was found that A. carbonarius was not able to grow on the two types of oilseeds with 0.82 or 0.86 aw. Also, the fungus was not able to grow on flax seeds with high water activity (0.98 aw). The OTA was only detected on flax seed samples with 0.94 aw at 20°C. On nyjer seeds, the highest concentration of OTA (271 μg/kg) was detected from samples with 0.98 aw incubated at 20°C for 5 days, while on flax seeds the highest OTA (146 μg/kg) was found on the seed samples with 0.94 aw incubated at 20°C for 15 days. Linear regression models also indicated that 0.98 aw was optimal for both fungal growth and OTA production on nyjer seeds. Overall, ground nyjer seed is better than flax seed to support growth and OTA production by A. carbonarius.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s