Do probiotic cultures withstand freezing? Should you freeze your beloved dairy?

Last week, I shared our updated Shelf Life Guide for Farm Fresh Food with you. And, gee, that sparked some wonderful conversations with readers. Great feedback. 

Multiple people were surprised that I did NOT recommend freezing yogurt and kefir. Their anecdotal stories told a different tale, one where you can freeze yogurt and kefir at home with varying success.

For example, some said that they freeze both yogurt and kefir with good results. Some said that they don’t notice a difference between fresh vs. frozen kefir, but freezing yogurt didn’t work well. Some said that freezing Greek yogurt works because it’s thick, but thinner yogurts get clumpy when thawed. 

The stories were a little inconsistent, but it showed me that freezing yogurt and kefir is possible. 

It’s not an issue of safety; it’s an issue of quality. Frozen foods are technically safe to eat indefinitely. But, they will degrade depending on the type of food, storage conditions, and time.

There was one BIG outstanding question from these conversations - what about microbiology? Can probiotic cultures survive freezing? I did some research.

I looked closely at a few studies about probiotics and frozen yogurt and kefir (1) (2) (3) (4). I saw a trend. All the charts and graphs looked something like this:

So… it seems that probiotic bacteria can survive when frozen. 

However, the population decreases over time. The longer yogurt or kefir is frozen, the less probiotic health benefits. At 2 months in the freezer, probiotic populations can decrease 15-50%. 

The amount of probiotic decrease depends on a variety of factors. Here are a few:

• The type of dairy product matters. One study showed that traditionally fermented dairy maintains its cultures the best over time (compared to those fortified with probiotics). 
• Adding an ingredient to the yogurt, natural or artificial, can increase or decrease probiotics. 
• The storage conditions and methods of thawing make a difference with quality loss.

So… if you want to freeze yogurt or kefir, you can certainly do so. Convenience and health benefits can be challenging to balance. This is a personal choice. 

Where do you get your probiotics? Would you give freezing yogurt or kefir a try? Do you make any compromises when it comes to food and health? 

I’d love to hear from you. Comment below (no account required) or contact us.