Is there a risk of botulism in fermented foods? Foodborne Botulism is very rare in the U.S. The environment that botulism prefers is the opposite of the environment we create when fermenting foods. The leading causes of foodborne botulism is improper canning techniques in home canned foods.
The main method of fermenting vegetables and sauerkraut on this blog is lacto-fermentation. This method creates an anaerobic environment (free of oxygen) where only lactobacillus bacteria can survive. The lactobacillus bacteria act as a preservative, keeping harmful bacteria from living in the ferment.
Will lacto-fermented pickles or sauerkraut give you botulism? No.
Fermenting foods creates an environment that botulism doesn’t like. In the article, “Debunking the Botulism Fear“, Tim Hall explains:
Fermenting foods creates an environment that is antagonistic to botulism. It’s what scientists call “competitive exclusion.” Beneficial bacteria begin to acidify the food, a condition C. botulinum doesn’t like. Adding salt to a ferment also reduces C. botulinum’s ability to grow, and encourages beneficial bacteria to take over. There are also other “competitive factors” that beneficial bacteria and fungi create in smaller quantities to exclude pathogenic varieties.
Debunking the Botulism Fear, is well researched and goes into depth on botulism and fermented foods. I highly recommend reading it.
Tips for Safe Fermentation
- Use fresh ingredients. Don’t use old, soggy cabbage or vegetables for your ferments. At this point they already started rotting on their own and could cause a ferment to go bad.
- Maintain good hygiene – Clean your vegetables. Wash your tools and hands with hot, soapy water before use.
- Use the exact amount of salt the recipe calls for. Some people are concerned about salt content, but it’s extremely important to create an environment that is inhospitable for harmful bacteria to survive. All my recipes are tested and use the right amount of salt for safe fermentation without being too salty.
- Salt distribution – Make sure salt is evenly distributed in the cabbage when making sauerkraut. When making pickles make sure salt is completely dissolved in the brine.
- Do not use iodized salt or table salt. Table salt has additives that can make the ferment go bad. I recommend fine high quality sea salt.
- Purified water – Make sure to always use either distilled or purified water when fermenting vegetables. Tap water contains chemicals like chlorine that harm good bacteria, which could lead to a bad ferment.
You don’t have to worry about botulism when fermenting foods. In fact, fermenting foods is safer than canning, because we are creating an environment where harmful bacteria, such as botulism, can’t survive.
Happy Fermenting!
Danielle
References
Botulism, MayClinic.org
Debunking the Botulism Fear
Miss Danielle,
I have a few questions on the subject of your article which is great by the way!
Some readers may fail to realize that we all have some of the botulism beast in our systems but not enough to cause a problems is how I understand thing to be…. Is this true??
Secondly, if a fermented food falls below a certain ph the beast can not grow. What if it happened to have grown in the ferment before the ferment reached the desired PH level? Also it is not the beast that causes the problem but the toxin it creates. This really bothers me when I see all the people making the garlic and honey ferments and are told to shake the jar once in a while to keep molds and stuff off by re coating the garlic floating on top of the honey. Isn’t it possible for the mold to grow really small colonies and produce toxin before they are washed off their garlic rafts by the recoating?
I ferment regularly and do not scoop mold off my ferments. I would maybe in a survival situation but I am not there yet :) But I do wonder about the unseen mold toxins like I described. Over a period of months I would think that these small unseen colonies could add up to a pretty large invasion?
Mike
Clostridium is found pretty much everywhere. In the human gut, soil, dust, on vegetables and fruits, etc. The reason these things don’t make us sick is they don’t provide a proper environment for clostridium botulinum to produce it’s toxin. It needs an anaerobic environment (less than 1% oxygen and they only require microscopic areas of low oxygen near the bacteria), at least 35% water, a PH above 4.6 and most importantly (and often overlooked) for botulinum to even produce the toxin it requires a specific bacteria parasite (called phages) to code for the toxin. The last reason is why you often don’t hear about people getting sick even from eating things that should in theory be a breeding ground for the toxin (such as badly home canned vegetables and tomato sauce, or garlic oils), it’s the reason why Botulism is rare.
So even if you have Clostridium Botulinum present in your fermenting food, the likely hood of them producing toxin is extremely small. Brine also helps to deter (though not completely prevent) bacteria growth as well. PH alone isn’t enough to deter Botulism because certain fungi can grow in PH below 4.6 (but not much below 3.8) which can raise the PH to levels to be high enough for Clostridium to thrive. This is why you have to add Citric Acid to safely can tomatoes and tomato sauce.
While fermenting is a low risk for Botulism growth, because of the dangers of the toxin and the microscopic amounts needed to make you sick (nanograms) you do need to make sure you follow the guidelines set in this article and also those set by the WHO and CDC/FDA.
Hi, I canned some jam and salsas this summer in small batches which I didn’t hot water bath. I also have kombucha and sourdough bread fermenting in my kitchen most of the time. My problem is some of my canned items have fermented. For example my green sauce (made with mostly green tomatoes and tomatillas) just fermented on me in the refrigerator. I have been eating out of this jar of salsa for a month – then pouf – it’s fermented. I this safe to eat? Is all the fermented food in my house causing thing to ferment rather than go bad?
Did you add acid to the tomatoes you canned to bring the ph down? Did you follow an authoritative canning guide? Are you sure you shouldn’t pressure can the salsa?
Absolutely- non-iodized salt. Wal-mart has some in the same type of paper canisters that the regular salt is sold in. I do believe “kosher salt” (anyone can correct me?) is also iodine free, as the reason for it BEING kosher salt is that it is USED in koshering- NO SALT IS ‘KOSHER’ IN ITSELF. Stop calling it that people, and stop calling for it in recipes- it serves no purpose whatsoever, unless the recipe is for fermenting or pickling!!!
Municipal tap water is perfectly fine for fermentation if you treat it to remove the chlorine or chroramines. I use 1/16 tsp (220 mg) of vitamin C crystals (ascorbic acid) per gallon of water, which is way more than enough to neutralize the chlorine or chloramines in a few minutes. I do this before adding salt.