Certain foods should never be stored in plastic containers because heat, acidity, fat, and fermentation can draw chemicals out of the plastic and into your food.
Acidic ingredients like tomato sauce and citrus can cause chemical leaching, hot foods accelerate the breakdown of plastics, oily foods pull out plasticizers, and fermented foods are too acidic and salty for long-term plastic storage. Glass or ceramic is safest for these items.

Most of us reach for plastic containers without a second thought. They’re convenient, lightweight, and practically overflowing from every kitchen cabinet in America. But not all foods play nicely with plastic, and some can actually break down the container itself. As a food science consultant and owner of Cape Crystal Brands, I’m often asked about best practices for storing ingredients safely. The truth is that certain foods can pull chemicals out of plastic far more easily than people realize.

Acid, heat, fat, and fermentation all change how plastics behave, sometimes increasing the risk of chemical migration. For readers who want to handle food with confidence, and for home cooks trying to protect both flavor and safety, here’s what to know about the foods that should never go into plastic containers and why choosing the right storage material matters.

What about acid foods?

Don’t keep tomato sauce or citrus in plastic as the acidity can leach chemicals out of the container and into your food.

What about hot foods?

You don’t want to put hot soups or stews into plastic as any type of heat is a cause for greater risk of chemical leaching. Heat breaks down the plastics faster.

What about fatty foods? 

Oily foods such as curry or cheese sauces seem to act like magnets for plasticizers, sucking them out over time into the food itself that you are trying to protect.

What about fermented foods?

Fermented foods need to go into glass or ceramic as the acids and salts of fermentation will eat through plastic over time, as well as compromise safety.”

FAQs

Why shouldn’t I store acidic foods like tomato sauce or citrus in plastic?

Acidic foods can weaken plastic over time, especially lower-grade containers. The acids attack the polymer structure, increasing the chances that chemicals—including dyes, stabilizers, and plasticizers—migrate into your food. Tomato sauce, lemon juice, and vinaigrettes are the top offenders. Glass is always the safest choice for acidic foods.

Can hot foods safely go into plastic containers?

Not recommended. Heat speeds up chemical leaching because it softens the plastic and increases molecular movement on both sides of the container wall. Hot soups, stews, or freshly cooked leftovers can cause significantly higher chemical transfer than cooled foods. Allow food to cool for 20–30 minutes before transferring—or use glass or stainless steel.

Why do oily foods pull chemicals out of plastic more easily?

Fats are excellent solvents. Sauces, curries, melted cheese, and oily leftovers can dissolve lipophilic (fat-loving) plasticizers found in many containers. Over time, this can affect both flavor and food safety. If the food is oily or fatty, switch to glass, ceramic, or high-quality stainless steel.

Credits

This article was inspired by questions from Lauren Thomann at Real Simple. 

More Food Questions America Is Asking

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🔶 Coming in Early 2026:

This topic — along with dozens of others — is explored in my upcoming book,
The Food Questions America Is Asking: How Journalists and Scientists Are Redefining What We Eat.