You may have heard rumors on blogs or social media that mixing pineapple and milk can be toxic — or even deadly.

On its own, pineapple (Ananas comosus) is a tropical fruit famous for its characteristic sweet but acidic flavor. In fact, it’s the world’s third most popular tropical fruit after bananas and citrus (1).

Milk alone is a highly nutritious drink that provides all three macronutrients — fat, protein, and carbs — as well as multiple vitamins and minerals (2).

If you’ve ever needed to mix these two ingredients in recipes, the longstanding rumor about combining pineapple and milk may have come to mind.

This article explains whether mixing pineapple and milk is safe.

chunks of pineapple next to a glass of milkShare on Pinterest
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Certain rumors claim that mixing pineapple and milk leads to stomachache, nausea, and diarrhea. A few more drastic myths imply that this combination may even be poisonous.

However, no scientific evidence supports this myth.

A study in rats even suggests that consuming both foods at the same time is perfectly safe. The rats received either a pineapple juice and milk solution at different concentrations, a toxic solution, or a nontoxic solution (3).

Those given the pineapple and milk mixture were just as healthy as those in the control group (3).

Thus, this mixture of ingredients won’t harm your health.

All the same, pineapple can curdle milk and turn it sour. As such, this combination might taste unpleasant if you eat these two ingredients on their own, but you shouldn’t worry about combining them in treats like smoothies or pineapple upside-down cake.

Summary

An animal study busts the myth that pineapple and milk harm your health when combined. These foods are completely safe to eat together.

Mixing pineapple and milk may result in milk curdling, which is often confused with spoiling.

The difference is that an overgrowth of spoilage bacteria causes spoiled milk, while in the case of curdled milk, the enzyme bromelain in pineapple is the cause.

Bromelain belongs to a group of enzymes known as proteases, which break proteins apart by cutting their amino acid chains. Bromelain acts upon casein, the main protein in milk (2, 4, 5).

While spoiled milk can be unsafe to drink, curdled milk is not unsafe — just sour.

In fact, mixing pineapple juice with milk is common in Indonesian cheesemaking, which counts on milk curd formation to produce soft cheeses (6).

Yet, this practice often creates a bitter taste due to an increase in bitter amino acids, such as tryptophan and proline, when bromelain breaks casein apart (6, 7).

Summary

Mixing pineapple and milk may lead to curdled, bitter-tasting milk due to the effect of pineapple’s bromelain on milk’s casein.

If you don’t want to risk curdling your milk with pineapple, you can try a few tips to get the most out of your recipe.

First, heat or cook the pineapple beforehand to denature the bromelain. Since this enzyme is heat-sensitive, high temperatures may inactivate it, preventing it from breaking casein apart and curdling the milk (8).

You can also opt for canned pineapple or pasteurized pineapple juice, as these products have already gone through a heating process. Just be mindful that they may contain added sugar.

Finally, you can swap cow’s milk out for a plant-based product like coconut, almond, or oat milks, which have significantly lower protein contents and aren’t as likely to curdle.

Summary

To prevent milk from curdling, cook pineapple before mixing it into your recipe. Otherwise, you can swap in canned pineapple or pasteurized pineapple juice, or use nondairy milk instead.

Mixing pineapple and milk is not toxic or dangerous.

However, it may result in curdled milk due to the effect of pineapple’s bromelain enzyme on milk’s casein protein.

If you want to avoid this reaction when following a recipe, cook the pineapple beforehand, use pineapple juice or canned pineapple, or try a nondairy milk.