Zucchini

Zucchini keeps about 1–2 weeks refrigerated. Store it unwashed and dry in the crisper, loosely bagged or wrapped in a paper towel.

Moisture is the enemy. Zucchini has very thin, unprotected skin, and any water sitting on it turns into a soft slimy patch within a day or two. Do not wash it until you cook it.

Handle it gently — the skin bruises easily and every bruise becomes a soft spot.

Smaller zucchini keep better than very large ones and taste better too; oversized specimens are watery and seedy.

Zucchini does not freeze well raw — it thaws limp and watery. Grated and squeezed dry, it freezes well for baking, and that is the best use for a glut.

Zucchini is a summer squash, which means it is harvested immature, before the skin has hardened and the seeds have developed. That immaturity is exactly why it is tender and edible skin and all — and exactly why it does not keep.

A winter squash such as butternut has a thick lignified rind and stores for months at room temperature. Zucchini has a thin, delicate cuticle a fraction of that thickness, offering little protection against moisture loss or microbial entry. It is essentially a young, growing tissue that was picked before it developed any defenses.

It is also around 95% water, so it both dehydrates readily — going rubbery and bendy — and collapses readily once cell walls are breached.

The typical failure is soft rot at one end or at a bruise: bacteria producing pectin-degrading enzymes turn the flesh mushy and slimy. It spreads through the fruit quickly once established.

A soft spot on an otherwise firm zucchini can be cut generously away. A zucchini that is limp throughout, slimy, weeping liquid, or moldy should be discarded.

Bitter zucchini is worth knowing about: rarely, squash produce cucurbitacins, which are intensely bitter and can cause gastrointestinal illness. If a zucchini tastes bitter, do not eat it.