济南市售小米和玉米中赭曲霉素A污染状况研究

Contamination of ochratoxin A in millet and maize sold in Jinan

目的了解济南市售小米和玉米中赭曲霉毒素A的污染情况。方法采用竞争抑制酶联免疫吸附测定(ELISA)法检测小米和玉米中赭曲霉毒素A的提取溶剂、检测条件、回收率等,并对其进行优化研究,并利用优化出的条件对济南市5个区市售小米和玉米中赭曲霉毒素A含量进行检测并评价。结果含有5%氯化钠的60%甲醇水溶液对谷物中赭曲霉毒素A的提取效果较为理想,检测的所有样品中,小米、玉米赭曲霉毒素A检出率分别为41%和38%,其中,超市小米赭曲霉毒素A检出率(56%)明显高于集市小米(26%)(P<0.05)。赭曲霉毒素A污染水平在0.40～4.45μg/kg之间,中位数为1.67μg/kg,集市和超市出售的小米、玉米中赭曲霉毒素A污染水平均无统计学意义(P>0.05)。本次检测所有样品中的赭曲霉毒素A含量均未超过国家规定的粮食中赭曲霉毒素A的限量标准。结论济南市售的小米和玉米中均不同程度地存在赭曲霉毒素A污染,但污染水平均未超过国家标准。

Objective To determine the contamination of ochratoxin A in millet and maize commercially available in Jinan. Methods An optimization study of the extraction solvent,testing conditions and recovery rates in detection of ochratoxin A in millet and maize by ELISA was carried out. M illet and maize samples collected from 5 districts of Jinan were analyzed under optimum conditions. Results Optimal ochratoxin A extraction was obtained when the extracting agent contained 5% sodium chloride and 60% methanol. For all the samples,the ochratoxin A detectable rate in millet was 41% ,while in maize it was 38% . The ochratoxin A detectable rate in millet from supermarkets was 56% ,which was significantly higher than that in the millet samples from markets （ 26% ） （ P 〈 0. 05） . The ochratoxin A concentration level ranged between 0. 40 and 4. 45 μg /kg,and the median was 1. 67 μg /kg. No significant difference in the ochratoxin A pollution level between millet and maize was found （ P 〉 0. 05） . Ochratoxin A contents in all samples were below the tolerance limit set by the state for ochratoxin A in grain. Conclusions The millet and maize commercially available in Jinan are contaminated by ochratoxin A to some extent,but the ochratoxin A content in the detected samples is below the tolerance limit.