在准备食物时，生熟食材要分开处理以防止交叉污染。

Always keep raw and cooked food separate during preparation to prevent ___cross-contamination.

厨房里应该用不同的砧板来避免生肉和蔬菜的交叉污染。

Different cutting boards should be used in the kitchen to prevent ___cross-contamination between raw meat and vegetables.