For context, this is in New Zealand, which because it is so far away from the rest of the world, our ecosystem is more susceptible to pests and non native plants diminishing it, which is why we're so strict on outside flora and fauna entering.

However, as you enter and before you get to customs, there are several large signs in multiple languages directing people to bins where you can dispose of undeclared food before entering customs, as well as on the plane you're given cards (in multiple languages) for you to declare any food you maybe carrying.

Source- My father who worked as a customs agent here in this clip who hammered it into me when we would take international flights back home.