The food is spoiled(rotten).

食物变质了

This milk went sour.

牛奶变质了。

This milk has gone bad.

牛奶变质了。

This milk tastes strange.

牛奶有股怪怪的味道。

The expiration date has passed.

过期了。

Food spoil easily during the summer.

食物在夏天很容易变质。

食物变质怎么说

Spoil还可以这样用：

He's always sending flowers.

他总是送花给我。

He absolutely spoils me!

他快宠坏我了。

Spoil the rod,spoil the child.

不打不成器。

Don't spoil the mood!

不要破坏气氛。

I don't want to spoil the fun, but could you turn the music down a bit?

我不想扫你兴，但你可以把音乐调小声点吗？

Too many cooks spoil the broth.

人多手杂，人多误事。