How long do onigiri last in the refrigerator? How do you keep them safe to eat?
This mainly depends on the filling as well as how much salt you use on the surface when you make the onigiri. If you use tuna with mayonnaise or any filling with mayonnaise in it, do not keep more than a day to be safe. If you use traditional fillings, especially umeboshi (pickled salty plums) they will last a lot longer, but no more than a couple of days. Umeboshi has natural antibacterial qualities, so is the ideal filling for onigiri that have to be held for some time – say, made the evening before to be eating or lunch on the road the next day. In any case, you should make onigiri with adequate salt on the outside, completely cooked fillings (never ever used raw/uncured fish or rare meat) and always use freshly cooked (ideal) or defrosted/reheated rice. If the weather is very warm and humid and you have used spoilable fillings such as tuna/mayo, consider packing your onigiri with an icepack (see Summer Bento Safety). You shouldn’t eat onigiri that has been around outside of proper
