Detection of ochratoxin A and assessment of human exposure risk in Rasa roxburghii by SPE-UHPLC-MS/MS

Solid-phase extraction ultrahigh-performance liquid chromatography-tandem mass spectrometry (SPE-UHPLC-MS/MS) was used to evaluate the contamination of ochratoxin A (OTA) and assessed the human exposure risk of OTA in Rasa roxburghii. A more suitable method for OTA extraction and purification of R. roxburghii was obtained. Treated 25 mL of R. roxburghii juice with enzymatic hydrolysis at a concentration of 0.06 mg/mL, filtered the resulting mixture and concentrated the filtrate to dry, then redissolved with 0.2 mL of methanol and diluted with 0.4 mL of ultra-pure water. Added sample solution to the activated hydrophilic-lipophilic balance (HLB) column, washed with 6 mL of ultra-pure water and purified by eluting with 6 mL of methanol. The eluent was collected and dried using nitrogen at 40 ℃, then redissolved in 1 mL of methanol and filtered for detection. The hazard quotient (HQ) values of all R. roxburghii fruit and juice, which were storage at room temperature, 4 and −20 ℃ from 0 day to 63 days, ranged from 0.077% to 35.792%, which were within the allowable limits for human consumption. From the perspective of OTA contamination, the results indicated that the maximal storage time of R. roxburghii fruit were 14 days at room temperature, 35 days at 4 ℃ and 63 days at −20 ℃. And the maximal storage time of R. roxburghii juice were 7 days for sealed storage and the same-day for open storage at room temperature, 14 days for sealed storage and 7 days for open storage at 4 ℃, and 63 days for sealed storage and 56 days for open storage at −20 ℃ during the experiment period. And all thirty samples randomly sampled from the market were OTA negative. The results of this study can lay a foundation for the formulation of OTA limit standards in fruits and juice in the future, and provide a reference for consumers to consume R. roxburghii more healthily.