Because of spam, I personally moderate all comments left on my blog. However, because of health issues, I will not be able to do so in the future.

If you have a personal question about LI or any related topic you can send me an email at I will try to respond.

Otherwise, this blog is now a legacy site, meaning that I am not updating it any longer. The basic information about LI is still sound. However, product information and weblinks may be out of date.

In addition, my old website, Planet Lactose, has been taken down because of the age of the information. Unfortunately, that means links to the site on this blog will no longer work.

For quick offline reference, you can purchase Planet Lactose: The Best of the Blog as an ebook on or Almost 100,000 words on LI, allergies, milk products, milk-free products, and the genetics of intolerance, along with large helpings of the weirdness that is the Net.

Sunday, July 12, 2009

Milk-Based Cultures in Stonyfield Soy Yogurt

I've seen several questions pop up about Stonyfield's O'Soy Soy Yogurt. Although it's a soy yogurt and none of the ingredients contain milk, the packaging contains a "CONTAINS SOY AND MILK" warning. Why? Because two of the six cultures that they use to make the yogurt are milk-based.

Michelle Civalier went the extra step and called the company in concern.

The representative informed me that this specific product has six probiotic cultures, two of which are grown in milk. (The details are proprietary, however, the spokeswoman did say there is no alternative method of growing those two cultures at this time.) The cultures ingest lactose, casein, and milk protein, meaning that those three things should not be present in the final product. What’s left of the milk after those parts are removed is present in the yogurt in amounts no greater than 5 ppm (parts per million). Stonyfield does not believe that these levels are high enough to cause a reaction in most sensitive or allergic people, but if there is concern, please consult a doctor before eating any of the product.
It's true that I've never heard of a documented reaction from anyone eating an O'Soy product. From the description given only the most extremely allergic would have even the possibility of a reaction. I'm sure most parents of allergic children would be concerned deposit this.

Civalier was. She asked:
Stonyfield promised to send my complaint to product development, though that didn’t provide me with any satisfaction as to why cultures that require milk to grow are being used in soy yogurt.

That's an interesting question. I haven't found any other soy yogurt to use milk-based cultures. They all claim to be dairy free. The Nancy's Yogurt FAQ page even explicitly states:
My son is allergic to dairy. Which of your products are completely casein-free?

All of our Organic Cultured Soy products are completely casein and dairy-free. We use nondairy cultures to culture our soy yogurt.

So it's not necessary to use milk-based cultures in soy yogurt. It's a choice that Stonyfield makes. Thus far it's been a successful choice, but it's one you need to think about.

You can find soy yogurts on the Nondairy Milk Alternatives - Other Nondairy Products of my Product Clearinghouse. I've made a note to the O'Soy Yogurt listing that states that it's made from milk-based cultures.

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Stephanie said...

FWIW, I'm lactose intolerant and I ate one of those yogurts under the assumption it was milk free. It was not pleasant.

ABryson said...

I'm disappointed with Stoneyfield as I avoid milk products because I'm vegan. If I wanted to consume milk based cultures I would eat milk based yogurt!

Laura said...

I'm lactose intolerant, and Stonyfield Soy yogurt doesn't bother me at all. Plus it tastes good, one of my favorite (mostly) soy yogurts. There's a clear warning on the package saying it contains milk-based cultures - if the milk is in small enough amounts to not bother most people who are sensitive or allergic, and it tastes better, why not use them?

If you don't want to consume yogurt with milk-based cultures, then just buy another brand.

Debbie said...

I agree with Laura, I am also lactose intolerant, I have read the packaging and it does say the cultures are made from milk. It is clearly labeled. Being lactose intolerant I read labels. If it is in small amounts I try it. O'Soy doesn't bother me either. I suggest if you have a problem with dairy then READ your labels. IF you don't want the dairy, THEN BUY SOMETHING ELSE! O'Soy is very good, and would like it to continue.

Debbie said...

I am lactose intolerant also, but I read all labels. I am aware of the milk based cultures in O'Soy, it is a small amount and doesn't bother me. Some people are quite sensitive to it, then reading of all labels is necessary for them. If you have a problem with it, then don't eat it, buy something else.

Anonymous said...

Recent update: O'Soy now is labeled as certified vegan, so should not affect anyone with dairy issues. :)