Acid stops browning. Packing stops bruising.

The best fix for brown apple slices is citrus acid in some form, and the bruise problem is mostly a packing problem. A 30-second dunk in lemon juice or a quick spritz will keep sliced apples and pears looking fresh for hours.

The browning is oxidation, and acid slows the enzyme that does it. Lemon, lime, pineapple juice, even orange juice all work. Don’t overthink it — a splash in a bowl of water, dunk the slices, shake off the excess. If you’re out of citrus, half a teaspoon of salt in a cup of water does the same trick; just rinse the fruit after or it’ll taste like a pretzel. Honey-water (about 2 tablespoons honey per cup of water) also works and adds a little sweetness.

For bananas, don’t cut them. The peel is the best anti-browning device ever invented. Pack the banana whole and slice it at lunch. If you absolutely must pre-slice, citrus will help, but bananas get mushy anyway, so it’s a losing game.

Bruising is simpler: it’s physical. Fruit gets beat up when it rattles around. Pack the lunch box so everything fits snugly — small containers instead of one big one, a napkin folded on top to fill empty space, that kind of thing. Also keep cut fruit away from bananas in the same box. Bananas pump out ethylene gas, which makes other fruit ripen faster and brown sooner. Whole apples take a beating fine, so if bruising is a real problem, just pack the whole apple. Cutting it at the table takes ten seconds.

Future you gets crisp fruit, which is the whole point of packing it.