Three Harmful Rice Washing Habits That Seem Harmless but Can Affect Your Health

Many people think that washing rice is a simple, even beneficial task—enhancing flavor and preserving nutrients. That’s why even experienced homemakers continue to make these common mistakes for decades without realizing the potential harm.

According to Dr. Tan Dunci (Taiwan, China), small actions like rinsing or soaking rice can have serious health impacts if done incorrectly. Below are three common mistakes that should be avoided as soon as possible:

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1. Washing Rice Directly in the Inner Pot of a Rice Cooker

Many households pour rice directly into the rice cooker’s inner pot and rinse it there for convenience. However, this seemingly harmless habit can be highly damaging.

Associate Professor Leung Ka-sing (Hong Kong Polytechnic University) warns that rubbing rice inside the inner pot can scratch its non-stick coating. Once this layer is damaged, the exposed metal underneath can oxidize and release harmful substances like PFOA—a compound that can remain in the human body for up to 3 years. PFOA has been linked to thyroid disorders, hormonal imbalances, high cholesterol, and even cancer. The U.S. Environmental Protection Agency (EPA) classifies PFOA as a possible carcinogen and notes its harmful effects on the immune system when accumulated over time.

Better alternative: Wash rice in a clean plastic bowl or colander before transferring it to the rice cooker pot for cooking.

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2. Skipping the Rice Washing Step Entirely

Some people believe that pre-packaged rice is clean enough or worry that rinsing will wash away nutrients, so they skip the washing step altogether. However, this can be a serious mistake.

Dr. Tan Dunci points out that the outer layer of rice grains can still carry dust, pesticide residues, bacteria, or even heavy metals like arsenic. If not washed off, these contaminants go straight into your body with the cooked rice. The World Health Organization (WHO) has warned that inorganic arsenic—often found in rice—is a known carcinogen that can affect the liver, kidneys, and nervous system if consumed over time.

Tip: Regardless of how “clean” the rice appears, always rinse it gently 1–2 times to remove surface impurities. No need to scrub hard—but don’t skip this crucial step.

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3. Soaking Rice for Too Long

To make rice softer or shorten cooking time, some people soak it before or after rinsing. While this can improve texture, excessive soaking—especially in warm weather—can cause health issues.

Dr. Tan Dunci warns that soaking rice too long at room temperature, especially in hot and humid conditions, encourages the growth of bacteria, mold, and toxins. One of the main concerns is bonkrekic acid, a toxin that can form during rice fermentation and cause severe digestive issues and metabolic problems. Long soaking periods also turn rice water into a breeding ground for bacteria, especially if it sits for over an hour at room temperature.

Safe soaking guidelines:

• For regular white rice, soak no more than 5 to 30 minutes.

• For brown rice, soak for up to 60 minutes max.

• If soaking is necessary, store rice in the fridge in a sealed container to limit bacterial growth.

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Conclusion:
Rice is a staple in many households, but even small missteps in handling it can have a big impact on your health. Avoid washing rice in the rice cooker pot, never skip rinsing, and don’t soak rice too long—especially at room temperature. With just a few mindful habits, you can keep your meals both delicious and safe.