News Details

On 10 June 2026, renewed concerns over food safety have emerged in Taiwan as reports of the illegal presence of boric acid and borax in traditional foods such as alkaline rice dumplings have resurfaced ahead of the Dragon Boat Festival. Health experts warn that these substances, which are not approved as food additives, may pose serious health risks including metabolic acidosis in severe cases. Despite long-standing bans, some food producers continue to use them to the improve texture, elasticity, and shelf life of products such as rice cakes, noodles, fish balls, and shrimp-based items. 

Health Authorities Warn of Toxic Risks from Boric Acid Exposure 

Medical professionals emphasize that ingesting boric acid, especially through repeated exposure, can accumulate in the human body and lead to systemic toxicity. 

Key health concerns include: 

• Potential metabolic acidosis in severe cases of poisoning.  

• Disruption of digestive enzyme activity.  

• Reduced appetite and impaired nutrient absorption.  

• Possible weight loss due to altered fat metabolism.  

• Reproductive toxicity, including testicular damage in male subjects, observed in animal studies. 

• Acute poisoning symptoms such as vomiting, diarrhoea, skin redness, and, in extreme cases, shock or coma.  

Health data indicates: 

• Adults may experience symptoms of poisoning after consuming approximately 1–3 grams.  

• Fatal doses are estimated at 15–20 grams for adults.  

• Children and infants are significantly more vulnerable, with much lower lethal thresholds.  

The International Agency for Research on Cancer (IARC) has not classified boric acid as a carcinogenic substance, however, toxicological concerns remain due to its cumulative effects in the body. 

Why Borax and Boric Acid Are Still Illegally Used in Food 

Borax (sodium tetraborate, chemical formula Na₂B₄O₇, CAS No 1330-43-4) is a boron-containing compound that can convert into boric acid in aqueous or acidic environments, including within the human stomach. 

Illegal use in food is mainly driven by its functional properties: 

• Enhances elasticity and chewy texture in food products.  

• Inhibits yeast and mould growth, acting as a preservative.  

• Prevents enzymatic browning in seafood, maintaining appearance.  

• Helps maintain the firmness and appearance of processed foods.  

However, both borax and boric acid are not included in Taiwan’s approved positive list of food additives and are strictly prohibited for use in food. 

Chemical Transformation Between Borax and Boric Acid 

Borax dissolves in water and undergoes chemical reactions to form boric acid and hydroxide ions. This process is central to its physical and functional behaviour. 

Key chemical insights: 

• Borax dissociates into sodium ions and tetraborate ions in water.  

• Tetraborate ions react with water to produce boric acid and hydroxide ions.  

• In acidic conditions, borax is fully converted into boric acid.  

• Boric acid can further interact with hydroxyl groups in food molecules to form cross-linked network structures that increase firmness and elasticity.  

In short, boric acid is often the final form present in food or the human digestive system after exposure to borax. 

Natural Occurrence and Industrial Uses of Boric Acid 

Boric acid is a weak inorganic acid that occurs naturally in the environment, including in seawater and in volcanic regions such as Tuscany in Italy, the Lipari Islands, and Nevada in the United States. 

Beyond its environmental presence, boric acid has multiple industrial and medical applications: 

• Used as a mild antiseptic for minor wounds and fungal infections.  

• Applied in diluted solutions for eye wash formulations under controlled concentrations.  

• Functions as an insect control agent. The United States Environmental Protection Agency (USEPA) has historically approved boric acid for controlling pests such as cockroaches, termites, ants, and fleas. 

• Used in wood preservation due to antimicrobial properties.  

• Plays a role in nuclear industry applications to control fission reaction rates.  

• Used in borosilicate glass production and buffer solutions in swimming pools.  

Despite its usefulness, its toxicity profile makes it unsuitable for use in food. 

Regulatory Position and Global Safety Standards 

International regulatory bodies have consistently prohibited the use of borax and boric acid as food additives due to safety concerns. 

Key regulatory positions: 

• The Joint Food and Agriculture Organization of the United Nations and World Health Organization Expert Committee on Food Additives (FAO/WHO JECFA) classifies borax and boric acid as unsuitable for food use.  

• World Health Organization (WHO) has established a tolerable daily intake (TDI) of 0.16 mg/kg body weight per day.  

• Many countries have banned their use in food processing.  

• The European Union allows extremely limited use in specific cases such as caviar preservation under strict conditions.  

• Taiwan enforces a positive list system for food additives, and borax is not approved.  

Ongoing Food Safety Monitoring Remains Essential 

Authorities continue to emphasize routine inspection and consumer awareness as key measures to prevent illegal borax usage in food products. 

Recommended precautions include: 

• Prefer packaged foods with clear ingredient labeling.  

• Avoid unverified street or informal food sources.  

• Support regulatory inspections and reporting mechanisms.  

• Be cautious of foods with unusually elastic or overly “Q” textures.  

As food safety concerns re-emerge during traditional festivals, experts stress that awareness and enforcement remain critical to reducing public health risks associated with illegal chemical additives.