Natto is a fermented food, but just because it’s fermented doesn’t mean it’s safe to eat indefinitely. In this article, we’ll explore whether it’s safe to eat natto after the expiration date, how to tell if it has gone bad, and the best ways to store it.
Can You Eat Natto After the Best before date?
Natto is fermented, so it doesn’t spoil immediately after the expiration date. However, its condition changes depending on how much time has passed. Let’s look at the different stages:
1-3 Days After the best before date
If properly stored in the fridge, natto that is 1 to 3 days past the expiration date is usually still safe to eat. You may not notice significant changes in taste or texture. However, natto stored at room temperature could spoil much faster, so always be cautious.
1 Week After the best before date
Natto becomes drier and harder after about a week past the expiration date. You might notice white crystals of amino acids on the surface, which are harmless. However, if there’s a strong ammonia smell or an unusual odor, it’s best not to eat it.
1 Month After the best before date
After one month, natto should not be consumed. Bacteria other than natto bacteria may have started growing, leading to spoilage. If you detect a sharp smell or a watery, slimy texture, it’s a sign that the natto has gone bad and should be discarded.
How to Identify Spoiled Natto
To ensure your safety, here are some key signs that natto has spoiled:
- Lack of Stickiness: Fresh natto is characterized by sticky strings when stirred. Spoiled natto loses this stickiness, or it may become overly slimy or watery.
- Color Changes: Normally, natto is a dark brownish color. If the color shifts to bluish or blackish shades, it’s a sign of spoilage.
- Foul Odor: While natto has a strong natural smell, spoiled natto takes on a more unpleasant, ammonia-like odor.
- Bulging Package: If the natto package is swollen, it’s an indicator that gas has been produced inside, which usually signals bacterial activity.
The Proper Way to Store Natto
To enjoy natto safely and preserve its quality, always store it in the refrigerator at below 10°C (50°F). For longer storage, natto can also be frozen. Make sure it’s tightly sealed in a freezer bag or wrapped in plastic. When you’re ready to eat it, simply thaw it in the refrigerator or at room temperature.
The Difference Between Fermentation and Spoilage
Many people think of natto as “already spoiled” because it’s fermented. However, there’s an important difference between fermentation and spoilage. Fermentation is the process by which beneficial microbes transform food, making it safe and often more nutritious. Spoilage, on the other hand, occurs when harmful bacteria proliferate, making the food unsafe to eat. Even fermented foods like natto can spoil if not stored properly.
Conclusion
While natto can often be eaten a few days after its expiration date, it’s important to check for signs of spoilage like changes in color, smell, or texture. One week past the expiration is typically still safe, but by one month, it’s better to discard the natto. To avoid spoilage, store your natto in the fridge or freezer and always trust your senses—when in doubt, throw it out!