Can soy sauce still be consumed after being opened and stored for a year?

Generally, soy sauce that has been opened and stored for a year is not recommended for consumption, even if it appears normal, as there may still be potential safety risks. If in doubt, it's safer to discard it outright. The detailed explanation is as follows:

Once opened, soy sauce is exposed to air and microorganisms such as bacteria. Even when refrigerated, one year is sufficient time for microbes to grow and multiply. Although the high salt content in some soy sauces provides a certain preservative effect, this protection gradually diminishes over prolonged periods after opening, potentially leading to microbial levels exceeding safety limits—though this contamination is usually invisible to the naked eye.

If opened soy sauce is not properly stored—for example, kept at room temperature or left unsealed—it may develop signs of spoilage more quickly, such as off odors, cloudiness, sediment, or mold. Consuming spoiled soy sauce may lead to gastrointestinal discomfort, including symptoms like abdominal pain, diarrhea, and vomiting, and in severe cases, could pose serious health risks.

It is recommended to consume soy sauce within 3 to 6 months after opening. Storing it sealed and refrigerated can help extend its shelf life. Always check for abnormalities such as unusual smell or cloudiness before use, and immediately discard if any signs of spoilage are detected. Avoid consuming soy sauce that has been open for an extended period to prevent health risks associated with microbial contamination.