contamination

However, contamination can occur at any point along the food chain, from field to table.

然而，污染沿着食物链可能在任何的点上发生，从田地到餐桌。

There is no evidence of contamination in our lab, and we have controlled for that all along.

我们的实验室不存在污染，在整个实验过程中我们都控制的很好。

Others have said that all of Mars should be protected as a wildlife preserve where we do everything possible to avoid contamination; on the assumption Martian microbes could exist.

假设火星上可能存在微生物，其他人就认为火星应该是我们做任何事来避免污染的野生动物保护区那样来被保护着。