Find out how frozen yogurt and ice cream stack up nutritionally.
This week I received not two, not three, but four emails from listeners with questions about frozen yogurt and ice cream. Obviously, it’s a topic I’ve been neglecting! Today, I’ll try to tackle all your questions, including whether or not frozen yogurt contains beneficial bacteria, what all those chemicals are doing in low-fat frozen desserts, and which ones might be the healthiest.
Does Freezing Kill the Beneficial Bacteria in Yogurt?
Grammar Girl has been using her ice cream maker to make frozen yogurt this summer. But she’s wondering if freezing the yogurt might affect the things that make yogurt so good for you. Kelly had the same question about making smoothies with yogurt and frozen fruit.
As you might remember from my episode on Fermented and Cultured Foods (#4), yogurt contains friendly bacteria that help keep your digestive system healthy. But these friendly flora are only helpful if they’re alive when you eat them. That’s why you should look for the words “Contains live and active cultures” on any yogurt package to be sure you’re getting the good stuff.
The good news is that freezing does not kill beneficial bacteria. In fact, it preserves them in a state of suspended animation until you eat them, at which point they warm up and resume their regular helpful activities, like fending off harmful bacteria, aiding with digestion, and producing certain vitamins. So, Kelly, you’ll get all the benefits of the yogurt in your frozen-fruit smoothies.
Does Frozen Yogurt Contain Live Cultures?
But I couldn’t answer Grammar Girl’s question about frozen yogurt for sure without seeing her recipe. Although it might seem an odd way to make a frozen dessert, many recipes start out by heating up milk, adding other ingredients, and then chilling the mixture before adding it to the ice cream maker. The bacteria in yogurt will die if they get any hotter than about 112 degrees F.
In Grammar Girl’s recipe, you heat up milk and sugar until it boils. Then you stir in the yogurt and some berries that you’ve pureed in the blender and chilled. If the yogurt is added to boiling milk, the beneficial bacteria will probably be destroyed. Grammar Girl suggested that if she adds the chilled berries first, it would cool the milk down enough that the bacteria in the yogurt would survive. She’s exactly right. As long as the mixture is cooler than 112 degrees F when the yogurt is added, she should be fine.
And that’s the problem with frozen yogurt you buy at the grocery or ice cream store. It has to contain a certain amount of actual yogurt in order to be labeled frozen yogurt. But if it’s heat-processed--and I’d assume that most commercial frozen yogurt is--you’re not going to get any beneficial bacteria in the finished product.