Chlorate formation and disinfection: what about it?

Recently, Coca-Cola recalled a number of products, including cola, iced tea and Fanta, due to excessive concentrations of chlorate. This incident highlights the importance of controlled and responsible disinfection methods, especially in the food and beverage industry. But what exactly is chlorate, how does it form, and why is it a concern? And how can alternative technologies help minimize risks?

What is chlorate and how is it formed?

Chlorates (ClO₃-) are chemical compounds that can form as byproducts during production, use and storage of chlorine-based disinfectants, such as sodium hypochlorite (NaOCl) or chlorine dioxide (ClO₂). Both agents are widely used because of their strong antimicrobial activity, but under certain conditions they can form chlorate. The formation of chlorate is affected by:

• Temperature: Higher temperatures accelerate the chemical breakdown of disinfectants, which promotes chlorate formation ⁽¹⁾.
• Storage time: The longer a disinfectant is stored, the more chlorate accumulates, especially with sodium hypochlorite ⁽²⁾.
• Concentration: Higher concentrations of chlorinated agents increase the risk of byproduct formation such as chlorate ⁽³⁾.

In industrial processes, such as the disinfection of machinery, packaging and process water in the food industry, these factors are very important. When used carelessly, elevated chlorate residues can form in water or food products, posing a risk to public health ⁽⁴⁾.

Why is chlorate an area of concern?

Chlorate can interfere with thyroid uptake of iodine, which is especially risky for vulnerable groups such as children, pregnant women and people with low iodine intake ⁽⁵⁾. Therefore, the Dutch Food and Consumer Product Safety Authority (NVWA) sets strict limits on chlorate residues in foods. A maximum residue limit (MRL) of 0.01 mg/kg (10 µg/kg) applies to most foods, unless a specific higher limit is set ⁽⁶⁾.

Exceeding these limits can lead to recalls and health risks, as demonstrated by the recent example of Coca-Cola. These incidents highlight the need to control chlorate formation.

HOCl: a modern alternative to conventional agents

Hypochlorous acid (HOCl), produced by an in situ technology such as the Watter system, offers an innovative approach to disinfection that eliminates many of the drawbacks of traditional agents. HOCl is produced in situ and applied directly, minimizing the risk of chlorate formation.

Advantages of HOCl and the Watter system:

• Minimal storage: It is produced directly on site, without long-term storage, thus avoiding chlorate formation ⁽⁷⁾.
• Low concentrations: HOCl works effectively at doses of 0.2 to 2 ppm, significantly lower than sodium hypochlorite, reducing the risk of byproducts such as chlorate ⁽⁸⁾.
• Controlled production: The Watter system regulates key parameters such as pH and temperature, contributing to efficient and controlled disinfection ⁽⁹⁾.
• Sustainability: By avoiding transportation and storage of chemicals, the system contributes to lower carbon emissions ⁽¹⁰⁾.

Conclusion: minimizing risks with innovation

Incidents such as the Coca-Cola recall demonstrate the importance of managing risks around chlorate formation in disinfection processes. Traditional bottled agents such as sodium hypochlorite and chlorine dioxide present challenges that can be mitigated through the use of in situ systems such as the Watter system.

As a result, Watter provides companies with a more efficient, sustainable and safer solution that contributes to regulatory compliance and higher food safety standards.

Do you have questions about HOCl or want to know more about the possibilities of the Watter system? Please feel free to contact us.

References

1. Stanford, B.D., et al. (2011). "Degradation of sodium hypochlorite: effects of temperature and storage conditions." Water Research, 45(3), 1063-1070.
2. American Water Works Association (AWWA). (2009). "Hypochlorite: An Assessment of Factors That Influence Product Quality." AWWA Report.
3. European Food Safety Authority (EFSA). (2015). "Risks for Public Health Related to Chlorate in Food." EFSA Journal, 13(6), 4135.
4. NVWA. "Residulimieten voor chloraat in levensmiddelen." Beschikbaar via: www.nvwa.nl.
5. World Health Organization (WHO). (2005). "Chlorate in Drinking-water: Background Document for Development of WHO Guidelines." WHO Technical Report Series.
6. Europese Commissie. (2020). "Verordening (EU) 2020/749 tot wijziging van Verordening (EG) nr. 396/2005 wat betreft maximumresidugehalten voor chloraat in of op bepaalde producten." Beschikbaar via: EUR-Lex.
7. Gordon, G., et al. (2005). "Minimizing Chlorate Formation in Chlorine Dioxide Applications." Journal of Water Supply: Research and Technology, 54(7), 471-482.
8. EFSA. (2014). "Scientific Opinion on the Public Health Risks Related to Chlorate in Drinking Water." EFSA Journal, 12(9), 3811.
9. American Water Works Association (AWWA). (2018). "Standard for Liquid Sodium Hypochlorite." ANSI/AWWA B300-18.
10. Interne documentatie Watter (niet openbaar beschikbaar).