Natural occurrence of tenuazonic acid and Phoma sorghina in Brazilian sorghum grains at different maturity stages

•This is the first study of tenuazonic acid occurrence in Brazilian sorghum grains.•A positive relationship was found between Phoma sorghina and tenuazonic acid contamination.•A high frequency of Phoma sorghina was recovered during sorghum grain development.•Tenuazonic acid was found in all sorghum maturity stages.

A survey of 100 samples of sorghum grains was carried out to determine Phoma spp. and tenuazonic acid (TA) contamination using molecular tools and LC-MS/MS. Sorghum samples were obtained at the following four grain maturity stages: milk (S1), soft dough (S2), hard dough (S3), and physiological maturity (S4). The results revealed a good correlation between Phoma and TA occurrence during grain development. The samples showed Phoma contamination with frequencies ranging from 2.4% (S1) to 87.4% (S4), and the molecular identification revealed P. sorghina as the only Phoma specie isolated. Tenuazonic acid was found in sorghum grains at all maturity stages. In S2, S3 and S4, 100% of the samples showed TA contamination with levels ranging from 20 to 1234 µg/kg. Low levels of TA were detected in 36% of the samples collected at S1 stage. This is the first report of tenuazonic acid in Brazilian sorghum grains.