Are store-bought eggs sprayed with chemicals? The surprising truth about egg processing

October 8, 2025 •

3 min read

In the United States, commercial eggs undergo a mandatory washing and sanitizing process before reaching your grocery store shelf, a protocol that sparks consumer curiosity. This procedure, often involving chemical sprays, is a key reason are store-bought eggs sprayed with chemicals? is a common consumer question, revealing a significant difference in food safety practices compared to other parts of the world.

Quick Summary

Store-bought eggs in the U.S. are washed and rinsed with sanitizing chemicals like chlorine to remove surface bacteria. This process removes the protective bloom, necessitating refrigeration to maintain food safety and quality.

Key Points

Mandatory Sanitation: Commercial eggs in the U.S. are legally required to be washed and sanitized with chemical sprays, often containing chlorine, to reduce the risk of pathogens like Salmonella.
Protective 'Bloom' is Removed: The washing process strips the egg of its natural, protective waxy coating, or 'bloom,' which leaves the shell's pores open to re-contamination.
Refrigeration is Essential: Because the bloom is removed, washed eggs must be kept refrigerated at or below 45°F to prevent bacteria from growing and entering the egg.
Chemicals are Food-Grade: The sanitizers used are food-grade and applied at regulated concentrations (e.g., 100-200 ppm chlorine), and are deemed safe by regulatory bodies like the USDA.
Optional Coatings for Preservation: Some eggs receive a second, optional food-grade spray, like mineral oil, after sanitizing to reseal the pores and extend shelf life.
International Contrast: In contrast to the U.S., many European countries prohibit washing eggs and instead focus on managing contamination within the hen house, preserving the natural bloom.
Separate from Contamination Incidents: The standard sanitizing process is not related to rare contamination events involving unauthorized pesticides, such as the 2017 Fipronil scandal.

The commercial egg cleaning process

Many consumers are unaware of the journey a commercial egg takes from the hen house to the carton. Unlike farm-fresh eggs that are often sold unwashed, eggs produced for major retail chains in the United States must go through a strict cleaning and sanitization process regulated by the United States Department of Agriculture (USDA). This procedure is designed to remove dirt, fecal matter, and other contaminants from the shell surface, significantly reducing the risk of bacterial contamination from organisms like Salmonella.

The steps of commercial egg washing

The standard process for cleaning commercial eggs typically involves several automated steps carried out in large-scale processing facilities, including wetting, washing with warm water and detergent, a critical rinsing and sanitizing step with chemicals like chlorine, drying, and sometimes an optional oiling or coating.

The crucial role of the 'bloom' and why it's removed

A hen naturally secretes a protective layer called the 'bloom' or 'cuticle' on the eggshell, which seals pores and prevents bacterial entry. While the European approach relies on this bloom by not washing eggs, the USDA's mandatory washing process for U.S. store-bought eggs removes it. This removal makes refrigeration essential for washed eggs to prevent bacteria from entering through the now-open pores, a concern less critical for unwashed eggs with their bloom intact.

Are the chemicals safe for consumption?

Sanitizing chemicals like chlorine, used in the final rinse at low, approved concentrations (100 to 200 ppm), are considered safe by food safety authorities. This process is vital for preventing contamination from dangerous pathogens like Salmonella. While minor residual chemicals may be present, the health risk is minimal compared to the risk of bacterial food poisoning. Washing hands after handling raw eggs is a good practice to avoid cross-contamination.

Comparison: US vs. European egg processing

To better understand the differences in approach, a quick comparison can be enlightening:


Feature	United States (USDA Regulated)	European Union (EU Regulated)
Egg Washing	Mandatory for most commercial eggs.	Prohibited for most Grade A eggs.
Chemical Spray	Standard practice for sanitization (e.g., chlorine rinse).	Not used for sanitizing Grade A eggs.
Natural Bloom	Removed during the washing process.	Intact, serving as the natural protective barrier.
Refrigeration	Mandatory for washed eggs due to bloom removal.	Not required, but can be used for longer storage.
Salmonella Control	Managed through washing and refrigeration.	Primarily managed through vaccination of hens and good hygiene practices.
Shelf Life	Standard refrigerated shelf life is 4-5 weeks.	Shorter shelf life at room temperature, longer if refrigerated.

Different coatings for different purposes

Beyond sanitizing sprays, some producers apply food-grade coatings for preservation. These are separate from the sanitization step. Examples include mineral oil to reseal pores and reduce moisture loss, and various edible films like shellac, corn zein, or whey protein to extend shelf life. Research also explores herbal or plant-based sprays for similar purposes. These coatings help maintain quality and freshness by blocking the shell's pores.

Conclusion

Yes, store-bought eggs in the United States are sprayed with chemicals as part of a mandatory, regulated cleaning process to sanitize the shells and reduce the risk of pathogens like Salmonella. This process removes the natural protective bloom, which is why refrigeration is immediately required to prevent recontamination. Consumers can trust that these eggs are safe when properly stored and handled with standard hygiene. Optional sprays like mineral oil may also be applied for preservation. The differences between U.S. and European methods highlight varying, yet effective, approaches to ensuring egg safety.

Food Safety and Inspection Service Guide to Eggs

Frequently Asked Questions

Yes, it is considered safe to eat commercially processed eggs. The chemicals used for sanitizing, such as chlorine, are food-grade and applied in low, regulated concentrations (100-200 ppm) to ensure food safety by killing harmful surface bacteria like Salmonella. The eggs are thoroughly rinsed afterward, and the levels are not considered a health risk.

The 'bloom' is a natural, invisible, protective layer on the eggshell secreted by the hen. It seals the shell's pores to keep out bacteria and prevent moisture loss. In the U.S., it is intentionally removed during the mandated commercial washing process to clean the egg surface thoroughly.

Store-bought eggs must be refrigerated because the commercial washing process removes the protective bloom, leaving the shell’s pores exposed. Refrigeration at 45°F (7.2°C) or lower is necessary to prevent bacteria that may have survived the wash from multiplying and entering the egg.

No. The practice of washing and spraying with a chemical sanitizer is common in the U.S. but differs internationally. Many European countries prohibit washing Grade A eggs and instead focus on flock health and hygiene to control contamination, thus preserving the natural bloom.

Some small-scale farms sell unwashed eggs with their natural bloom intact. These can be wiped with a dry cloth to remove dirt, but wet washing would remove the protective layer. For commercial-level sanitization, methods like UV light or organic sanitizers are being explored, though chemical sanitizers remain the industry standard.

You should not wash store-bought eggs because the washing process removes the bloom, leaving the shell porous. A washed egg already has an increased risk of contamination if not properly stored. Washing it again, particularly in cool water, can draw surface bacteria into the egg's interior.

A sanitizing spray, typically chlorine-based, is used to kill surface bacteria as part of the mandatory commercial cleaning process. A mineral oil spray is an optional, food-grade coating applied afterward to reseal the egg's pores and reduce moisture loss, effectively extending its shelf life.