LAUSR

BACKGROUND The widespread incidence of rice false smut has caused extensive contamination of ustiloxins, accumulated in rice around the world. Until now, there is a lack of knowledge on the natural occurrence of ustiloxins in paddy. Additionally, the development of efficient removal methods is still a challenge, which remains underutilized and unexplored. RESULTS In the current study, three main ustiloxins, ustiloxin A (UA), ustiloxin B (UB), and ustiloxin G (UG), were simultaneously determined by UPLC-MS/MS, in 206 paddy samples collected in 2021 from 5 rice-producing provinces in China. UA was the most predominant ustiloxin with an occurrence of 46.1% and an average concentration of 49.71 μg/kg, followed by UB (31.1%, 13.31 μg/kg) and UG (18.4%, 9.19 μg/kg). While no targeted ustiloxins were detected in white rice samples randomly collected from supermarkets in Shanghai. To reveal the causes, two approaches were tested for the removal of the ustiloxins: most of the targeted ustiloxins (>93%) were removed in brown rice by husking, and subsequently, all targeted ustiloxins (100%) were removed by whitening. CONCLUSION A wide distribution of ustiloxins was discovered in paddy samples in this study. The contaminations of UA were significantly different between origins, with the highest occurrence in paddy from Shanghai and Jiangsu, southeast coast provinces in China. UG was also found in paddy for the first time and was highly correlated with that of UA and UB. To achieve an efficient removal, the combination of husking and whitening has been verified to be a practicable and promising way to ensure food safety. This article is protected by copyright. All rights reserved.