When purchasing cauliflower, look for a clean, creamy white, compact curd in which the bud clusters are not separated. Spotted or dull-colored cauliflower should be avoided.
A bucket of salty water is the best way to get rid of bugs that could be found in such a compact vegetable. You need to completely submerge the head in water, so a bucket that can fit the whole head is best. Add about 2 Tbsp salt per quart warm water to get it nice and salty. Submerge the head, florets down (they float, so a weight to keep it submerged will help). Let sit 5-10 minutes, remove, and rinse very thoroughly.
The salt in the water helps to kill the bugs and encourage them to let go. You should see bugs either floating or at the bottom when you remove the cauliflower.
If you don’t need the head whole when cooking, core and cut into desired size prior to soaking.
Store uncooked cauliflower in a plastic bag in the refrigerator where it will keep for up to a week. To prevent moisture from developing in the floret clusters, store it with the stem side down. If you purchase pre-cut cauliflower florets, consume them within one or two days as they will lose their freshness after that. Since cooking causes cauliflower to spoil quicker, consume it within two to three days of placing in the refrigerator after cooking.