Tuesday, July 13, 2010

Science and Hysteria in Lacto-Fermenting

Over the next few days I will be posting several methods of making lacto-fermented vegetables. One question which always arises is the 'safety' of eating home ferments. I know, because I myself threw away what was probably a perfectly good 2 gallon crock of garlic dills just because I 'assumed' they might be bad, based on the kahm yeast on top!

In my nearly 70 years of existence in this lifetime, I have watched the increasing media-induced hysteria about sanitation in foods. You see ads for hand-sanitizers everywhere, and there are chemical wipes for hands and cart handles at most grocery store entrances (for cold and flu germs, not food germs). Some doctors suggest we may be too clean, giving rise to the inability to fight off normal bacterial infections. Today even most of the foods we buy are sanitized, irradiated, or cooked until all life, good and bad, in them is dead.

When I was a kid in school, we were taught the average human in this country eats more than a cup of dirt over a lifetime. I suspect that figure is much lower now, and few farmers even know how to taste the dirt to see if it is sweet, much less actually do it!

Most of us who home can foods wouldn't touch a jar of another's home-canned vegetables with a 10-foot pole if we don't know the person who made them, lest they contain odorless and tasteless botulism and kill us.

Don't get me wrong... I absolutely believe in cleanliness, and especially in the kitchen and my foods. But because of our learned fear of potentially contaminated food, it is hard for us to accept the safety of food made in a jar and left at room temperatures for several days, then weeks or months more in somewhat cooler room temps, all without any refrigeration. 

Most people freak if they even see butter sitting out on a counter. My mother always kept butter in a covered dish in a cabinet; summer temps rarely exceeded 75ºF and if they did, the butter merely got a little bit softer. I keep my butter in a butter bell (on the counter) which has water in it; the water keeps the butter soft at higher temps than my mother's home had.

Leaving foods unrefrigerated for 2 weeks or more can be very disturbing to people who were not raised with a crock of pickles in a hall closet, basement or garage. USDA Research Microbiologist Fred Breidt (who works at a lab at NC State University where they have been studying fermented foods since the 1930's) says properly fermented foods are actually safer than raw vegetables that may have been exposed to pathogens like E. coli on a farm across the nation or world somewhere.

So, what makes lacto-fermented foods safe?
Breidt said that there are no documented cases of food-borne illness from fermented vegetables, and they are much safer for novices to make than home-canned vegetables. Pressurized canning creates an anaerobic environment that increases the risk of deadly botulism, particularly with low-acid foods. "With fermented products there is no safety concern. The reason is the lactic acid bacteria that carry out the fermentation are the world's best killers of other bacteria."

While the lactic acid keeps the bad bacteria from growing during the fermentation process, the salt and oxygen in the jar or crock initially create an environment where botulism cannot live (aerobic). As the lactic acid begins to form it creates a gas which slowly pushes out the oxygen, but by then enough lactic acid has been produced to lower the pH to an acidic environment where bad bacteria will not survive.

So... take a deep breath, turn off the media warnings in your head, and take the plunge. Your grandma would be proud!


  1. I like this post a lot. I am curious, too. I have this musty basement and I want to ferment down there, but I've always avoided it because it is so musty. Do you think I could do it? I mean, all the action does happen under the surface of the crock.

  2. I don't see why not, but later this week I have 2 posts on fermenting with closed jars (1 with Fido jars, and 1 with Ball canning jars), either of which might make you less worried...


I'd love to hear what you think about my posts! We all learn together.