Brown fruit is a packing problem, not a fruit problem.

That sad, browning apple slice is mostly an oxygen problem, and the bruise next to it is a “you parked it under a granola bar” problem.

Browning is a chemical reaction: cut fruit’s enzymes hit air and turn brown. Acid stops the reaction. So toss sliced apples, pears, or peaches in a squirt of lemon (or lime) juice, then seal them in an airtight container. A hard-sided one with a tight lid keeps air out and keeps them from getting smushed. Some people do the fruit-in-a-vinegar-water trick, but lemon gets the job done without making the apple taste like a salad.

Bruises are physical. Fruit in a lunch box gets beaten up by heavier stuff: yogurt, a thermos, a sandwich. The fix is separation and cushion. Put fruit in its own little compartment or a silicone cup, and if the fruit is soft — berries, sliced mango, or a peach — wrap it loosely in a paper towel inside that cup. That towel absorbs moisture and cushions jolts. Keep the fruit on top in the lunch bag, or at least not underneath the thermos.

If you’re packing whole fruit, there’s nothing to brown, and bruising mostly comes from it rolling around. Piece of folded paper towel or a bento divider stops that too.

Your kid isn’t going to eat a brown apple slice, so thirty seconds of acidity and a little TLC beats the sad side dish every time.