This is a global pest, one of the species of grain beetles. They infest stored grains, seeds, flour, etc., all over the world. You should see the little larvae in your seed collection....they are what feed on the seeds.

Commercially, seed warehouses are treated with horticultural or food grade diatomaceous earth (DE). Non food seeds will be chemically treated in storage.

Consumers can bring flours, pasta, bird seed, etc., home and store them in the freezer or fridge (after a freezer treatment). Can't recommend that with viable seed. DE is the way to go when you collect and store seeds in the future.

Food/horticultural grade DE is edible, by the way, and can be used to protect coriander seeds even if you use them as a personal culinary spice.