BRC英文版第七版4.10.3.4条款中有一条：Tests carried outusing separate test pieces containing ferrous metal, stainless steel andtypicallynon-ferrousmetal, unless the product is within a foil container where ferrous only may beapplicable.我们公司的物料是放在不锈钢储罐的，金属探测器的标准测试卡是否可以只用铁和不锈钢两种？一定要有非铁的测试卡吗？