关键词: 真菌毒素, 农产品, 混合污染, 长三角地区

Abstract:

【Objective】 The purpose of this survey was to investigate the natural occurrence and contamination characteristics of 40 mycotoxins in agro-products (wheat, maize, rice, tomato and peach) from Yangtze Delta Region, so as to provide a scientific basis for the supervision of agro-products. 【Method】 A total of 720 ago-product samples, including 120 wheat samples, 150 maize samples, 150 rice samples, 150 tomato samples and 150 peach samples, were collected from supermarkets, farmers and farmers' markets in Shanghai, Anhui, Jiangsu and Zhejiang in 2019. The grain samples were extracted with water and acetonitrile containing 1% (V/V) formic acid, and fruit and vegetable samples were extracted with acetonitrile containing 1% (V/V) formic acid. The extractions were salted out with sodium chloride and anhydrous magnesium sulfate, and the concentrations of 40 kinds of important mycotoxins were determined by ultra-performance liquid chromatography-tandem mass spectrometry. Chi-square test and one-way analysis of variance (ANOVA) were utilized to investigate the mycotoxin contamination levels among different types of agro-products in different regions, while Spearman’s rank correlation coefficient was used for the analysis of the relationship between mycotoxin concentrations and temperature and humidity.【Result】In 720 samples, a total of 36 kinds of mycotoxins were detected, mainly including aflatoxins, ochratoxins, alternaria toxins, fumonisins, deoxynivalenol (DON) and its modified forms and zearalenone (ZEN). The detection rate of mycotoxins in total agro-products was 75.3%. Among the positive toxins, fumonisin B ₁ (FB₁) was the most frequently detected (49.0%), followed by tenuazonic acid (TeA) (37.5%), fumonisin B₂ (FB₂) (35.7%), tentoxin (Ten) (29.6%), fumonisin B₃ (FB₃) (29.3%), ZEN (22.6%), DON (21.4%), 3-acetyl-deoxynivalenol (3-ADON) (10.7%), ochratoxin A (OTA) (10.4%), ochratoxin B (OTB) (8.1%), deoxynivalenol-3-glucoside (D3G) (7.2%), ochratoxin C (OTC) (6.4%), aflatoxin B₂(AFB₂) (5.8%) and 15-acetyl-deoxynivalenol (15-ADON) (5.4%). Additionally, 59.5% of the agricultural products were contaminated with two or more mycotoxins, and the maximum number in one sample was 23. According to GB 2761-2017, the concentrations of AFB₁ in one maize sample, OTA in one rice sample, ZEN in 6 wheat samples and 2 maize samples exceeded the relative limit standards. The contamination levels of mycotoxins in agro-products from the Yangtze River Delta region were relatively lower, compared with other studies, which showed significant types and regional differences. The most prevalent mycotoxins were Ten, TeA, DON in wheat, fumonisins in maize, Ten, TeA, fumonisins in rice, and ochratoxins, alternaria toxins, fumonisins in fruits and vegetables, respectively. Regionally, maize samples from Zhejiang were seriously contaminated with DON and ZEN, while the highest concentrations of fumonisins were detected in Anhui maize samples. The detection rates and concentration levels of DON and ZEN in rice samples from Jiangsu were significantly higher than those from other regions. The contamination levels of Ten, TeA, FB₁, DON and ZEN in grain samples were in significant correlation with temperature and/or humidity, while no statistical relationship was found in tomato and peach samples. 【Conclusion】 Agro-products from the Yangtze River Delta region were contaminated by various mycotoxins. Although the overall contamination level was relatively low, the multi-mycotoxin co-occurrence in single sample was frequently found, which should be given enough considerations.

Key words: mycotoxins, agricultural products, co-occurrence, Yangtze Delta Region