Food expires at the same rate regardless of its country of origin. That said, foods commonly used in Japanese cuisine, such as sushi rice, tare and ramen, expire at different rates, and each have different “best by,” or best eaten by, dates. For example, sushi rice might keep four to six days before spoilage occurs, but it’s best eaten the of preparation for best taste. Expiration dates, on the other hand, are a different story. If you eat food past its expiration date, you risk contracting foodborne illnesses, which affect 48 million people each year, according to the Centers for Disease Control and Prevention. You can’t overestimate the importance of food safety.
Cooked rice and sushi rice
Cooked rice lasts four to six days in the refrigerator. Whether it’s sushi rice or plain white rice, you should eat it within four days to six days. An unpleasant, acidic odor, far different than that of vinegar, tells you it has turned. To minimize the chances of spoilage, only reheat rice once; multiple reheatings and coolings put food in the temperature danger zone, or the temperature gradient between 40F and 140F where bacteria thrive. Store leftover rice in the refrigerator an airtight container (after it has cooled).
Miso soup
Miso soup lasts three to four days in the refrigerator. Although miso paste keeps for about one year in the refrigerator due to its high salt content, miso soup does not due to the introduction of water, which causes bacteria to multiply rapidly. Store miso soup in an airtight container in the refrigerator. You can keep miso soup indefinitely in the freezer, but it will start to lose quality after about three months. Turned miso soup has a sour, vegetative odor and, in some cases, pools of bacterial spores on its surface.
Dashi broth
Dashi broth lasts about one week in the refrigerator. Like all seafood-based stocks, broths and fumet, you have about a week to use dashi. Similar to miso paste, the ingredients used in dashi — katsuobushi (dried and smoked bonito tuna flakes) and kombu (dried kelp) — have near-indefinite shelf lives, but when you add water, you introduce bacteria, which shortens the shelf life of the overall dish. You can store dashi in the freezer indefinitely. For convenience, freeze dashi in ice cube trays and, when frozen, store the cubes in a freezer bag. Then, when you need an extra shot of umami in dishes like okonomiyaki (to boost the flavor of the batter) and takoyaki (also to boost the flavor of the batter), simply grab a cube, defrost it and add it in.
Tare
Tare keeps three to four days in the refrigerator. Despite its high sodium and sugar content, tare doesn’t stay fresh longer due to the chicken stock and scallions it contains, or its “weak links.” Tare’s other ingredients, soy sauce, brown sugar, sake, mirin, and garlic have relatively long shelf lives on their own, but the perishable ingredients bring the shelf life of the preparation down to the lowest common denominator — three to four days. Tare freezes well, and will hold its flavor for up to six months without any noticeable changes in its flavor profile. Like with dashi, freeze tare in ice cube trays and store it in freezer bags so you can add a cube or two to your ramen as needed.
The takeaway
- Refrigerate all the foods listed here within two hours of cooking them.
- Never reheat foods more than once to keep them out of the temperature danger zone.
- If you have doubts about a food’s freshness, don’t risk it — toss it.
- Store all food in airtight containers in the refrigerator.
- Rice of all types is best eaten the day of cooking it for best taste and texture.
- Always reheat food to 165F or, if you can’t measure a food’s temperature using a thermometer, reheat it until it’s hot and steaming.
