Assessment of mycobiota in Thai pigmented rice: Insights into ochratoxin A and citrinin production by Aspergillus and Penicillium species

Pigmented rice has gained interest for its nutritional and health benefits attributed to its bioactive compounds. Despite these advantages, the vulnerability of pigmented rice to mycotoxin contamination poses a major concern. This study examined the mycobiota of seven Thai pigmented rice varieties, with a focus on fungi capable of producing ochratoxin A (OTA) and citrinin. The study analyzed 110 pigmented rice samples and found that the Aspergillus section Aspergillus was predominant (50 - 82.35%), followed by Penicillium species (12.50 - 70.59%). One isolate of A. carbonarius from Aspergillus section Nigri (1/112) and two isolates from Aspergillus section Circumdati (2/61) - A. steynii and A. flocculosus - produced OTA. However, none of the Penicillium species produced OTA, though citrinin production was notable in P. citrinum (128/280). The study found that the Black Jasmine rice and Red Jasmine rice varieties were more susceptible to mycotoxin production, while the Luem Pua glutinous rice and Hom Nil rice varieties displayed more resistance to the accumulation of both mycotoxins. These findings should guide targeted strategies to mitigate mycotoxin risks and ensure the safety of pigmented rice in the food chain.