Give cut fruit a citrus bath before packing it

The simplest fix for cut fruit browning is a quick dunk in cold water with a little lemon juice or vinegar before you pack it.

Browning is just oxidation — an enzyme reaction that triggers when the fruit cells get sliced. Acid slows that enzyme way down. Use about a tablespoon of lemon juice or white vinegar per cup of water, soak the cut fruit for two to three minutes, then drain and pat it dry. Vinegar sounds scary but you won’t taste it at that dilution.

If you’re packing apples or pears, this works better than squeezing lemon straight onto the slices because it coats the whole cut surface evenly. You can also use a commercial product like Fruit Fresh (it’s just ascorbic acid) if you want zero flavor change. Or skip the hassle and pack fruits that don’t brown: grapes, berries, melon, orange segments, mango.

The five minutes of prep saves you from sad brown apples at lunch.