E925 - Chlorine

At a glance

• What it is: a reactive gas that dissolves in water to form a powerful sanitizer
• Why it’s used: to reduce harmful microbes during produce washing and food processing
• Where you’ll find it: wash water for fresh produce and process water in factories (not usually on labels)
• Safety: regulated uses and residual limits are set by authorities to protect consumers
• Alternatives: ozone, peracetic acid, and chlorine dioxide

Why is Chlorine added to food?

Chlorine is used as an antimicrobial in rinse and process water to help reduce bacteria, viruses, and molds on food and food-contact surfaces. In the United States, the Food and Drug Administration (FDA) permits its use in water for washing and peeling fruits and vegetables under specified conditions, because it functions as a sanitizer rather than as a flavor or nutrient ingredient.¹

What foods contain Chlorine?

You won’t usually “see” chlorine in foods. It’s added to water used to rinse or process foods like leafy greens, tomatoes, melons, and other fresh produce. Because it performs its job during processing and is not intended to have a technical effect in the final food, it is generally treated as an incidental additive (a processing aid) and is exempt from declaration on the ingredient list under U.S. labeling rules.²

What can replace Chlorine?

There are several other sanitizers that can serve the same purpose:

• Ozone gas dissolved in water, allowed by FDA as an antimicrobial agent for processing foods.³
• Chlorine dioxide, another oxidizing sanitizer often used in process water.
• Peracetic acid solutions, organic acids, and other approved antimicrobials used where appropriate.

Choice depends on the food, equipment, water quality, and regulatory requirements.

How is Chlorine made?

Most industrial chlorine is produced by the chlor‑alkali process, which electrolyzes salt water (brine) to make chlorine gas, hydrogen, and sodium hydroxide. Modern plants use membrane cells to separate the products and prevent mixing.⁴

Is Chlorine safe to eat?

When used correctly, chlorine in processing water is considered safe. For context, the U.S. Environmental Protection Agency (EPA) allows up to 4 milligrams per liter (4 ppm) of chlorine as a residual disinfectant in drinking water, a level set to protect public health.⁵ In food plants, chlorine is used under specific conditions (such as concentration controls and rinsing practices) to ensure it does not leave harmful residues or affect the finished food.¹

Chlorine-based disinfectants can form byproducts like chlorate. European food-safety authorities have assessed exposure to chlorate from foods and set health-based guidance values, highlighting the importance of controlling treatment conditions and residues.⁶

Does Chlorine have any benefits?

Yes. The main benefit is food safety: properly managed chlorine wash systems can reduce microbial loads on produce and in processing environments, helping to lower the risk of foodborne illness. U.S. Department of Agriculture guidance for meat, poultry, and egg processors lists chlorine among safe and suitable antimicrobial ingredients when used as directed.⁷

Who should avoid Chlorine?

Most people do not need to avoid foods processed with chlorinated water. However, chlorine gas and high concentrations can irritate eyes and the respiratory tract; individuals with asthma or known sensitivity to strong oxidants may be more susceptible to irritation from fumes in occupational or poorly ventilated settings.⁴ This concern relates to exposure to the gas or strong solutions, not to trace levels remaining on foods rinsed under proper conditions.

Myths & facts

• Myth: Chlorine is added to food to make it last forever. Fact: It’s used to sanitize water and surfaces; it doesn’t “preserve” food in the package.

• Myth: If chlorine is used, it must show up on the ingredient list. Fact: When used as a processing aid and not functional in the final food, labeling is not required under U.S. rules.²

• Myth: Chlorine in produce wash makes foods unsafe. Fact: Regulators set strict use conditions and residual limits to keep consumers safe.¹⁵

• Myth: There are no alternatives to chlorine. Fact: Ozone and other approved sanitizers can serve similar roles, depending on the process.³

Chlorine in branded foods

You’re unlikely to find “chlorine” on a nutrition label, even if it was used in the wash water for a salad mix or cut fruit. That’s because it functions as a processing aid and, when properly used, doesn’t have a technical effect in the finished food and is exempt from labeling in the U.S.²

References

Footnotes

1. 21 CFR 173.315 — Chemicals used in washing or to assist in the peeling of fruits and vegetables. U.S. Food and Drug Administration. https://www.ecfr.gov/current/title-21/part-173/section-173.315 ↩ ↩² ↩³

2. 21 CFR 101.100 — Food; exemptions from labeling (incidental additives/processing aids). U.S. Food and Drug Administration. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-101/section-101.100 ↩ ↩² ↩³

3. 21 CFR 173.368 — Ozone. U.S. Food and Drug Administration. https://www.ecfr.gov/current/title-21/part-173/section-173.368 ↩ ↩²

4. ToxFAQs for Chlorine. Agency for Toxic Substances and Disease Registry (ATSDR), U.S. Department of Health and Human Services. https://wwwn.cdc.gov/TSP/ToxFAQs/ToxFAQsDetails.aspx?faqid=197&toxid=36 ↩ ↩²

5. National Primary Drinking Water Regulations — Disinfectants (chlorine MRDL = 4.0 mg/L). U.S. Environmental Protection Agency. https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations ↩ ↩²

6. Scientific Opinion on risks for public health related to the presence of chlorate in food. European Food Safety Authority (EFSA). https://efsa.onlinelibrary.wiley.com/doi/10.2903/j.efsa.2015.4151 ↩

7. FSIS Directive 7120.1 — Safe and Suitable Ingredients Used in the Production of Meat, Poultry, and Egg Products. U.S. Department of Agriculture. https://www.fsis.usda.gov/policy/fsis-directives/7120.1 ↩