食品接触用不锈钢材料中镍、铅元素的迁移规律

Migration law of nickel and lead from food-contact stainless steel to food

以食品接触用304、316不锈钢为研究对象,探究不锈钢中Ni、Pb在20、40、70℃恒温条件,以及加热煮沸、高压蒸汽灭菌特殊条件和组合工况3类常用食品加工条件下的迁移行为规律。实验采用全浸没法,利用电感耦合等离子体质谱检测法监测重金属迁移量随时间的变化情况。结果表明,不同工况条件对Pb迁移量变化趋势影响较小,不锈钢与食品模拟液接触后Pb立即少量迁出,后期迁移量几乎不随时间变化,最终迁移量维持在15μg/L左右。不锈钢主要组成元素Ni迁移量随时间延长而不断增加,且316不锈钢中Ni迁移量高于304不锈钢;Ni迁移量、迁移速率均随加工工况温度升高而增加;由于前期30 min特殊工况预处理时,Ni迁移量较快增长,组合工况条件下后期恒温长时间迁移过程中,其迁移速率减缓,且最终迁移量基本相等。为预测不锈钢中Ni迁移变化情况,研究对实验数据进行拟合,发现在恒温迁移过程中,其迁移规律符合溶出动力学经验公式。

In this study, 304 and 316 stainless steels were used as the research object to explore the migration behavior of nickel and lead in stainless steel under three common food processing conditions, namely 20, 40 and 70 ℃ constant temperature conditions, heating boiling and high-pressure steam sterilization severe conditions and combined conditions. Total immersion method and inductively coupled plasma mass spectrometry(ICP-MS) were used to monitor the change of heavy metal migration. The result showed that different working conditions had little effect on the variation trend of Pb migration. After the stainless-steel contacted with the food simulation solution, a small amount of Pb immediately migrated, and the migration almost did not change with time. The final migration amount of Pb was maintained at about 15 μg/L. The migration amount of Ni increased with time, and it was higher in 316 steel than that in 304 steel. Moreover, the migration amount and migration rate of Ni increased with the rising temperature in processing conditions. Due to the rapid increase of Ni migration during 30 min pretreatment under special conditions in the early stage, the migration rate slowed down in the late constant temperature and longtime migration under combined conditions, and the final migration amount was basically the same. In order to predict the migration of Ni in stainless steel, the experimental data were fitted and it was found that the migration law was consistent with the empirical formula of stripping kinetics during the process of constant temperature migration.