Does White Rice Have Mycotoxins? Answering the Pressing Question

November 28, 2025 •

5 min read

According to the Food and Agriculture Organization of the United Nations, up to 25% of the world's cereals, including rice, are contaminated with mycotoxins. This raises a critical question for many consumers: does white rice have mycotoxins, and what can be done to minimize the risk?

Quick Summary

Yes, white rice can have mycotoxins, but proper agricultural practices, processing, and storage significantly reduce this risk. Effective prevention focuses on controlling moisture and temperature to inhibit mold growth. Specific cooking methods can also help lower contamination levels in consumer-level products.

Key Points

Prevalence Varies: Mycotoxin contamination in rice is not guaranteed but is a known risk, particularly when grains are stored improperly in warm, humid conditions.
White vs. Brown: The milling process to create white rice removes the outer layers where mycotoxins often accumulate, generally resulting in lower concentrations than in brown rice.
Storage is Key: Proper storage in airtight containers in a cool, dry, dark place is the most effective method for consumers to prevent mold growth and mycotoxin production.
Cooking Matters: Boiling rice with excess water and discarding the water after cooking can significantly reduce mycotoxin levels, as some toxins are water-soluble.
International Standards: Regulations from bodies like the Codex Alimentarius Commission set maximum mycotoxin limits, protecting consumers by controlling contamination in the food supply chain.
Visual Inspection: Visually inspecting rice for moldy, discolored, or shriveled grains before cooking is a simple but important safety precaution.

Understanding the Threat of Mycotoxins in Rice

Mycotoxins are toxic secondary metabolites produced by various fungi, including species of Aspergillus, Penicillium, and Fusarium. While these molds can infect many crops, rice is particularly susceptible due to its high starch content and the humid, warm conditions often present during cultivation and storage in many parts of the world. The presence of mycotoxins is not an automatic outcome of rice production, but depends heavily on agricultural and post-harvest conditions.

Common Mycotoxins Found in Rice

Several types of mycotoxins can contaminate rice, with aflatoxins and ochratoxin A being the most prevalent and concerning for public health. Other mycotoxins, like fumonisins and citrinin, are also occasionally detected.

Aflatoxins (AFs): Produced mainly by Aspergillus flavus and A. parasiticus, aflatoxins, especially aflatoxin B1, are potent carcinogens and immunosuppressants. Contamination is a particular risk in tropical and subtropical climates where humidity and heat are high. The milling process that creates white rice can reduce aflatoxin levels, but proper storage remains crucial.
Ochratoxin A (OTA): Produced by Aspergillus and Penicillium species, OTA is known for its nephrotoxic (kidney-damaging) properties. Contamination often occurs during improper storage. Parboiling and cooking can help reduce OTA levels.
Citrinin (CIT): Another mycotoxin produced by certain Penicillium species, citrinin is also a nephrotoxin and has been found in rice, though less frequently reported.

How Mycotoxins Affect White Rice vs. Brown Rice

Many people wonder if the milling process that removes the outer bran layer to create white rice impacts mycotoxin levels. Studies suggest that milling can help reduce contamination, as many toxins are concentrated in the outer layers, but it does not eliminate the risk entirely.

Comparison of Mycotoxin Contamination: Brown Rice vs. White Rice


Feature	Brown Rice	White Rice	Explanation of Differences
Processing	Only the outer husk is removed, leaving the bran and germ layers intact.	Further processed to remove the bran and germ, leaving only the starchy endosperm.	This removal process can reduce contamination, but may also remove nutrients.
Mycotoxin Levels	Can contain higher concentrations, especially of aflatoxins, as the bran layer can harbor mold.	Generally has lower concentrations of mycotoxins due to the removal of the outer layers during milling.	This is a statistical trend, not a guarantee. Improper storage of white rice can still lead to contamination.
Storage Vulnerability	More susceptible to fungal growth and mycotoxin production due to higher nutrient content in the bran and germ.	Less vulnerable during storage due to the removal of nutrient-rich layers that support mold growth.	Airtight, cool, and dry storage is essential for both to prevent contamination.

Prevention and Mitigation Strategies for Consumers

For consumers, controlling mycotoxins in rice involves both careful selection and proper handling. The World Health Organization and other food safety experts offer clear guidelines.

Buy from reputable sources: Purchase rice from trusted retailers and brands known for good quality control. Countries with strong food safety regulations often have lower contamination rates.
Inspect and discard: Before cooking, visually inspect rice for signs of mold, discoloration, or shriveled grains and discard any contaminated grains. This is a crucial step, especially for grains that may have been stored improperly.
Proper storage: Keep rice in a cool, dry place and in an airtight container to prevent moisture and insects from getting in. Glass or BPA-free plastic containers with secure lids are ideal. For long-term storage, freezing is an excellent option.
Washing and cooking: While mycotoxins are heat-stable, cooking with excess water (like boiling) can help reduce levels as some toxins leach into the water. Always discard the water after cooking. Washing rice thoroughly beforehand can also help remove some surface toxins.
Rotate stock: Use older rice first to prevent long-term storage issues that can lead to contamination. Buying smaller quantities is also advisable if you don't use rice frequently.

Conclusion

Does white rice have mycotoxins? The answer is yes, it can, but it is not an inevitability. The level of risk is heavily dependent on pre- and post-harvest handling, and significantly impacted by storage conditions. While the milling process for white rice removes some of the risk by taking away the toxin-prone bran layer, consumers must still take responsibility for proper storage at home. By following best practices for inspection, storage, and cooking, individuals can minimize their exposure to these potentially harmful compounds. Staying informed and proactive is the most effective defense against mycotoxin contamination in rice and other grains. For further details on food safety standards and mycotoxins, consult the official guidelines from organizations like the FDA.

The Role of Global Standards in Mycotoxin Control

International bodies like the Codex Alimentarius Commission set standards for mycotoxins in food to protect consumer health and facilitate fair trade. These standards, based on evaluations from experts convened by the WHO and FAO, guide national regulations and influence agricultural practices globally. For rice, these regulations enforce maximum permissible limits for specific mycotoxins, such as aflatoxins. This provides a critical layer of protection for consumers worldwide.

The Impact of Processing on Mycotoxin Levels

Different processing methods can have varying effects on mycotoxin concentrations. For white rice, the milling process is known to be effective at removing some contaminants. Studies have shown that mycotoxins are often concentrated in the outer parts of the grain, so their removal during polishing helps. For example, parboiling rice, which involves soaking and steaming paddy rice before milling, has been shown to reduce mycotoxin levels through leaching and thermal degradation. However, these methods are not foolproof. Some heat-stable mycotoxins, like certain ochratoxins, can survive normal cooking temperatures. This is why post-processing handling and consumer-level practices are so important.

Consumer Responsibility: Beyond Storage

In addition to proper storage, consumers can take other steps to further reduce mycotoxin exposure. Cooking rice with excess water and draining it can reduce mycotoxin content, particularly for aflatoxins, which have some solubility in water. A study showed that cooking rice at 100°C for 12 minutes reduced aflatoxins, with brown rice showing a higher reduction percentage than white rice, though washing white rice was still beneficial. Being mindful of the source and freshness of the rice is also key. Buying grains and nuts as fresh as possible and avoiding long-term storage can mitigate the risk of contamination. Lastly, maintaining a diverse diet is a good strategy to avoid overexposure to any single potential contaminant.

Frequently Asked Questions

Mycotoxins are toxic compounds produced by certain fungi or molds, such as Aspergillus and Penicillium. They are found in rice due to fungal infection that can occur both in the field and during post-harvest storage, especially under warm, humid conditions.

Brown rice is generally more susceptible to mycotoxin contamination because the mycotoxins tend to concentrate in the outer bran layers of the grain. In contrast, the milling process that produces white rice removes these outer layers, typically resulting in lower concentrations.

Cooking methods like boiling can help reduce mycotoxin levels, but they don't completely destroy them, as many mycotoxins are heat-stable. Boiling rice in excess water and then draining the water is most effective, as some of the water-soluble toxins are removed during the process.

The best way is to store rice in a cool, dark, and dry location using an airtight container. This prevents moisture from promoting mold growth and keeps out pests that can introduce contamination. Refrigeration or freezing is also a great option for long-term storage.

You cannot reliably detect mycotoxins by simply looking at the rice, as contamination can occur even without visible mold. However, you should always discard any rice that shows obvious signs of mold, discoloration, or smells musty.

Washing rice can help reduce some of the surface-level contamination. However, because mycotoxins can penetrate deep into the grain, washing alone is not enough to guarantee safety.

Yes, many countries and international bodies, such as the Codex Alimentarius Commission, have set maximum permissible limits for mycotoxins like aflatoxins in rice and other cereals to ensure food safety.