Occurrence of multi-mycotoxin in paddy rice in Guangdong Province

Objective To understand the contamination pattern of mycotoxin in paddy rice in the main rice-growing regions of Guangdong Province, and analyze the distribution difference of mycotoxin in different areas, so as to provide basis for the implementation of precise prevention and control measures. Methods A total of 120 paddy rice samples were collected from eight cities in the Pearl River Delta, northern, eastern and western Guangdong during 2018 and 2019, and were analyzed for 16 mycotoxins by multiple reaction monitoring mode of ultra performance liquid chromatography-tandem mass spectrometer. Results Among the 120 paddy rice samples, 19.17% (23/120) were positive for mycotoxins, and the main polluants were aflatoxins and fumonisins. FB1 were detected in 9.17% (11/120) of the samples, followed by 8.33% (10/120) for AFB1. Two samples had the AFB1 concentrations above the tolerance limit of 10 μg/kg. The detection values were 73.90 and 18.80 μg/kg, respectively. Among 6 trichothecene mycotoxins, only deoxynivalenol (1.67%, 2/120) and its acetyl derivatives[0.83% (1/120) for 3-Ac-DON and 0.83% (1/120) for 15-Ac-DON] were found. ZEN was found in 3.33% (4/120) of the samples. Additionally, 1.67% (2/120) of the paddy rice samples were positive for sterigmatocystin. The ochratoxin A, nivalenol, T-2 and HT-2 mycotoxins were not found in the paddy rice samples. The co-occurrence of two or more mycotoxins was confirmed in 8.33% (10/120) of the paddy rice samples, mainly combination was AFB1 and other mycotoxins. The contamination patterns were different in the eight cities. The paddy rice samples from Zhanjiang was mainly contaminated by FB1, FB2, DON and 3-Ac-DON. Samples from Heyuan were mainly contaminated by AFB1, AFB2, sterigmatocystin, FB1 and FB2. The concentration levels of ZEN, DON and 3-Ac-DON were relatively higher in samples from Shaoguan. Conclusion The paddy rice samples from Guangdong Province were contaminated by multiple mycotoxins, and the pollution patterns were different in different areas. In terms of the co-occurence of mycotoxins, some measures should be conducted to assess the exposure risk, reduce the damage, and protect the consumers food safety