Does Cooking Fermented Food Kill Bacteria?

Do you like to enjoy your fermented food at warm or hot temperatures? Maybe some nice warm sauerkraut as a side to your meat and potatoes or even some hot kimchi soup?

When eating your fermented food in this way, you might have wondered what happens to the probiotics. Maybe one of the main reasons you eat fermented food is because of the good bacteria that provide some nice health benefits.

So, does cooking fermented food kill bacteria? It will, but only if you heat it to temperatures greater than 115 °F. Read on to learn more.

microscopic image of bacteria

What Is Fermented Food?

For those of you who don’t know, let me first explain what fermented food actually is.

To keep things simple, fermented food is food that’s created through microbial growth as well as enzymatic action. While that might sound odd, if you’ve ever taken a sip of beer or wine, you’ve already had a taste of what fermented food is like.

In addition to alcohol, here are some other popular foods that are fermented:

We see these products all the time. Yet most of us probably don’t think about what’s actually in these foods or how they can affect our health.

When we hear the word “bacteria,” our mind usually associates it with something negative, like an infection. Certain types of bacteria can make us sick, and we make a point to use cleaning products to kill bacteria and avoid contact with it. However, the kinds of bacteria found in fermented food are different than you might think.

Fermented foods contain “good bacteria” (referred to as probiotics), which can help our bodies balance out the number of bad bacteria we’ve got and have benefits like improving our digestive health and preventing disease.

kimchi on a white plate

Bacteria in Fermented Food

Fermented foods are becoming increasingly popular, and consuming some of these products has become a sort of new health craze.

The amount of living microorganisms can vary between different fermented foods, and some fermented foods don’t even have them.

You’ve probably heard of the benefits of eating yogurt containing probiotics. Probiotics, like those in yogurt, are made up of two things: good bacteria and yeast.

The most common types of good bacteria in probiotics are lactobacillus and bifidobacterium, and the most common type of yeast in probiotics is Saccharomyces boulardii. These types of good bacteria can live in different parts of your body, such as your gut, urinary tract and skin. They help perform essential tasks like aiding in digestion, fighting off bad bacteria, and keeping harmful bacteria out of your bloodstream.

We all love to reap the benefits of eating foods that contain these helpful additions to enhance our health. However, when we cook these foods, are we killing the probiotics?

Does Cooking Fermented Foods Kill the Probiotics?

When we ferment foods or buy them from the store, they’re usually at room temperature or are refrigerated, and these are the temperatures at which we typically eat them.

But if you like to heat up your sauerkraut or eat your kimchi in a soup, you might have wondered what happens to the probiotics if you’re heating or cooking the foods that contain them. The answer is that you would be killing these probiotics but only at a certain threshold.

dish of sauerkraut potatoes and roasted pork leg

Cooking or heating fermented foods kills off the good bacteria that make up the probiotics, making them lose their potential gut health benefits. However, this only happens at temperatures above 115 °F (more on this in the next section).

Many of us consume our meals in a hurry or on-the-go. Often, we turn to our microwaves to prepare our meals or even to heat leftovers for convenience. So, if you’re microwaving your probiotic-containing foods, you’re killing off those good bacteria.

When you buy fermented foods that are canned, they’ve been heated before canning to kill off any bacteria that would cause them to spoil while on the shelf (a process referred to pasteurization, often done in the food industry to prolong the shelf-life of foods). Because of this, they’ll typically have fewer probiotics compared to fermented foods that are refrigerated.

If you’re a person who eats fermented food for the probiotic benefits, the best things you can do are to:

  • Buy refrigerated fermented foods (which you’ll usually find jarred)
  • Better yet, ferment food yourself at home

Furthermore, if you’re fermenting your own food at home, you should know that heat isn’t the only thing that stops fermentation. Acids like vinegar will halt the fermentation process too. Click here to learn more.

What Temperature Kills Probiotics?

While it may be tempting to use some of these foods containing probiotics while cooking your meals, cooking them at high temperatures or for an extended period can kill those good gut bacteria.

One study found that foods cooked at 140°F for fifteen minutes kill off over 95% of bacterial cultures.

When fermented foods reach a temperature of 115°F, probiotics begin to get killed. So when cooking dishes containing these kinds of foods, make sure that you pay attention to your recipe’s details.

Since fermented foods like miso, kimchi, and sauerkraut are already safe to eat when you purchase them from the store, none of these products need to be cooked to any designated internal temperature when you get them home. You can consume them as-is.

If you do want to consume or serve these foods warm, you can always heat them for a short time on a low setting on your stovetop. It is recommended that the cooking time is minimal so you don’t lose out on those good bacteria in your food prep process.

Following these easy tips can make or break the health benefits you get from your fermented foods.

Cooking Fermented Food FAQ

Does Cooking Kimchi Kill Probiotics?

Cooking kimchi can kill its probiotics if the kimchi reaches a temperature of 115°F or over. Remember, kimchi is safe to eat as is and doesn’t have to be cooked.

If you do want to heat it up, use a low temperature and don’t heat it for too long. If you really want to get probiotics benefits from dishes like kimchi soup or kimchi fried rice, throw in the kimchi at the end. Or, you can divide the amount of kimchi you need for the dish in half, and throw in the second half at the end.

Does Cooking Miso Kill Probiotics?

Cooking miso can kill its probiotics if the miso reaches a temperature of 115°F or over.

If you’re making miso soup, don’t throw it in with the boiling water too early because the boiling water will kill the probiotics. Instead, wait until the soup is done, take it off the heat, then mix it in. The soup should be hot enough at this stage to dissolve the miso into it but not hot enough to kill off the probiotics.

Does Cooking Sauerkraut Kill Probiotics?

Cooking sauerkraut can kill its probiotics if the sauerkraut reaches a temperature of 115°F or over. Remember, sauerkraut is safe to eat as is and doesn’t have to be cooked.

If you do want to heat it up, use a low temperature and don’t heat it for too long. Another tip is to add the sauerkraut at the end, which will make sure it isn’t cooked for too long.

Does Cooking Tempeh Kill Probiotics?

Cooking tempeh can kill its probiotics if the tempeh reaches a temperature of 115°F or over.

Tempeh is tricky because some say you can’t eat it raw while others eat it raw without any problems. My recommendation is to first check the packaging to see if it should be cooked, and follow the instructions for preparation.

Does Heat Kill Probiotics in Yogurt?

Heating yogurt that contains probiotics will kill the probiotics if the temperature reaches 115°F or over.

Also, if the heat it too high, the yogurt will likely start to curdle. If you need to heat yogurt, keep the heat on low or add it into the dish at the end.

In Summary

If you’re looking for a change from eating your fermented foods cold or at room temperature and want to heat them up, it’s essential to be careful with how much time you spend heating them on your stovetop. Doing so will ensure you get the most nutritional benefits from them.

Expanding your understanding of the health benefits associated with eating fermented foods is a good idea. And by learning how to prepare fermented foods properly, you’ll be able to preserve and reap the benefits of the probiotics in your food!

So next time you’re in the grocery store, remember to avoid the canned sauerkraut and try to find it in the refrigerated section instead. Or even better, make your own sauerkraut at home. And when it comes time to heating it up, be sure to watch the temperature you use.