Is Custard a Probiotic? The Truth About This Comfort Food

November 8, 2025 •

3 min read

Many people assume that because some dairy products are fermented and contain probiotics, all dairy-based desserts are equally beneficial, but is custard a probiotic? The truth is that traditional custard recipes, which involve high heat, effectively eliminate any potential live bacteria, unlike other fermented dairy foods.

Quick Summary

Traditional custard is not a probiotic source because the heat used during preparation kills beneficial live cultures. Specialized or modified versions can contain probiotics if live cultures are added post-cooking.

Key Points

Not Probiotic by Default: Traditional custard is not a probiotic food because its cooking process involves heat that kills any live cultures present in the ingredients.
Heating Kills Bacteria: The pasteurization of milk and the subsequent cooking or baking of the custard mixture eliminate the beneficial microorganisms required for a food to be considered probiotic.
Easily Made Probiotic: You can create a probiotic custard by adding live-culture ingredients like Greek yogurt or kefir after the cooked base has cooled down.
Live Cultures Are Key: For a product to be probiotic, it must contain live and active microorganisms in adequate amounts that provide a health benefit to the host.
Check Labels and Temperature: Always look for "live and active cultures" on labels and remember that refrigerated, unheated foods are the most reliable source of probiotics.
Prebiotics vs. Probiotics: Prebiotics are non-digestible fibers that feed good bacteria, while probiotics are the live bacteria themselves.

What Exactly Are Probiotics?

Probiotics are defined as "live microorganisms that, when administered in adequate amounts, confer a health benefit on the host". These beneficial bacteria live in your digestive system and contribute to a balanced gut microbiome. They help improve digestion, enhance immune function, and protect against harmful bacteria. Some well-known probiotic-rich foods include yogurt, kefir, kimchi, and kombucha.

How Probiotics Work

Probiotics function in several ways in the gut:

They compete with harmful bacteria for resources.
They can strengthen the immune system.
They help maintain the gut lining.
They produce beneficial compounds like short-chain fatty acids.

Is Traditional Custard Probiotic?

No, traditional custard is not a probiotic food. Standard preparation involves heating milk, eggs, and sugar, which kills any live bacterial cultures, including those that might have been in the milk. Pasteurized milk, a common ingredient, already has most bacteria killed during processing. Therefore, cooked custard does not contain the live microorganisms needed to be probiotic. While custard's smooth texture is easy to digest, its benefits are not due to probiotics.

Creating a Probiotic Custard

To make a custard with beneficial bacteria, add live cultures after cooking and cooling.

Methods to Add Probiotics After Cooking

Use Fermented Ingredients: Stir in probiotic-rich ingredients like Greek yogurt or kefir once the custard base is cool. Heat destroys these cultures, so cooling is essential. Recipes exist for blending probiotic yogurt into chilled custard.
Add Probiotic Supplements: Tasteless probiotic powders or drops can be mixed into cooled custard to add specific strains and doses.
Include Prebiotics: Consider adding prebiotics, fibers that feed good gut bacteria, like chicory root, which is sometimes found in commercial dairy-free custards.

Probiotic Custard vs. Traditional Custard: A Comparison


Feature	Traditional Custard	Probiotic Custard (Modified)
Probiotic Content	None	High (added post-cooking)
Preparation Method	Cooked/Baked	Cooked base, cultures added after cooling
Key Ingredients	Milk, eggs, sugar	Milk, eggs, sugar + yogurt/kefir/probiotic
Digestive Benefit	Easy texture, no live cultures	Supports gut microbiome
Best For	Classic dessert	Healthier dessert alternative

What to Look for When Seeking Probiotic Foods

Not all fermented foods are probiotic. Heat processing can kill the beneficial microbes.

Identifying Probiotic Products

Check the Label: Look for "live and active cultures" or "contains probiotics".
Consider Storage: Probiotic foods are often refrigerated to keep cultures alive.
Processing Matters: High heat processing, like baking or pasteurization, destroys live bacteria.

The Difference Between Probiotics and Prebiotics

Probiotics are live beneficial microorganisms, while prebiotics are fibers that feed these bacteria. Eating both can create a healthier gut environment.

Conclusion

Traditional custard is not probiotic due to the cooking process. However, adding probiotic ingredients like yogurt or kefir after cooling can create a gut-friendly version. For consistent probiotic intake, rely on known sources like yogurt and kefir. Consult a healthcare professional before making dietary changes, especially with health conditions.

Common Probiotic Foods List:

Yogurt with live cultures
Kefir
Kimchi
Sauerkraut (unpasteurized)
Kombucha
Miso
Certain aged cheeses
Tempeh
Sourdough bread (some)

For more information on gut health and nutrition, consider visiting the Cleveland Clinic's Health Essentials website.

Frequently Asked Questions

No, baked custard does not contain probiotics. The high heat used during baking, which is necessary to set the eggs and milk, kills any live bacterial cultures that might have been in the ingredients.

Custard is not a probiotic food like yogurt primarily because of the way it's prepared. While both are dairy-based, custard is cooked, which destroys live cultures, whereas yogurt production involves controlled fermentation where live cultures are maintained and not cooked afterward.

When custard is cooked, the heat effectively pasteurizes the mixture, killing all the live bacterial cultures. For a food to be probiotic, the microorganisms must remain alive when consumed.

Yes, you can make a probiotic custard at home. The best way is to prepare a traditional cooked custard base, let it cool completely, and then stir in a probiotic-rich ingredient like plain Greek yogurt or kefir.

The main difference is the addition of live, active cultures. A probiotic custard has live microorganisms added after cooking, offering gut health benefits, while a regular custard is a classic dessert with no live cultures.

No, the presence of milk in custard does not guarantee probiotics. Unless the custard is made from a fermented milk product or has live cultures added after cooking, it will not be probiotic.

A prebiotic custard is one that contains prebiotic fibers, such as chicory root, which serve as food for the beneficial bacteria already in your gut. This is different from a probiotic custard, which contains the live bacteria themselves.