Abstract: An utra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established using quick, easy, cheap, effective, rugged, and safe (QuEChERS) pre-treatment to investigate the production and distribution of five Alternaria mycotoxins including tentoxin (Ten), alternariol (AOH), alternariol monomethyl ether (AME), altenuene (ALT) and tenuazonic acid (TeA) in whole fruits, healthy pulp and healthy peel of citrus inoculated with Alternaria alternate. The results demonstrated that the contents of various Alternaria mycotoxins produced in whole fruits, healthy pulp and healthy peel changed differently with increasing lesion diameter. TeA, Ten, AME and AOH were detected in all tested parts of the fruit. Among these, the average concentration of TeA was the highest, ranging from 3.05 × 103 to 55.88 × 103 μg/kg and from 65.35 to 40.68 × 103 μg/kg in lesion and non-lesion areas, respectively. The concentrations of Ten, AME and AOH in the infected location were in the range of 69.16?373.94, 22.63?1 395.82 and 8.18?689.19 μg/kg, respectively, while in the health location, the values were in the range of 0?67.56, 0?195.96 and 0?301.91 μg/kg, respectively. ALT was detected in both healthy peel and infected whole fruits (up to 16.61 μg/kg) rather than healthy pulp. These results indicate that Alternaria mycotoxins produced in infected citrus can rapidly spread from the infected to the healthy parts, resulting in the accumulation of a large amount of mycotoxins in citrus. Therefore, we should pay more attention to this problem in fresh food processing and risk assessment to ensure consumer safety.

Key words: Satsuma mandarin, Alternaria mycotoxins, ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), distribution pattern