How to store eggs, and why two regulators give opposite instructions
The United States requires refrigeration at 40 degrees Fahrenheit or below. European rules say Class A eggs shall not be washed and should in general not be refrigerated before sale. One processing step explains the split.
- 01
The American rule: 40 degrees Fahrenheit, original carton, 3 weeks
Buy eggs only if sold from a refrigerator or refrigerated case, open the carton and make sure the eggs are clean and the shells are not cracked, store promptly in a clean refrigerator at a temperature of 40 degrees Fahrenheit or below using a refrigerator thermometer to check, store eggs in their original carton, and use them within 3 weeks for best quality (FDA). Hard-cooked eggs, in shell or peeled, are used within 1 week after cooking.
- 02
The European rule: no washing, and no artificial chilling
Class A eggs shall not be washed or cleaned, before or after grading, and shall not be treated for preservation or chilled in premises or plants where the temperature is artificially maintained at less than 5 degrees Celsius; eggs kept below 5 degrees during transport for not more than 24 hours, or on retail premises for not more than 72 hours, are not considered chilled (Commission Regulation (EC) No 589/2008).
- 03
The stated reason is condensation, not cold
Cold eggs left out at room temperature may become covered in condensation, facilitating the growth of bacteria on the shell and probably their ingression into the egg; therefore eggs should be stored and transported preferably at a constant temperature, and should in general not be refrigerated before sale to the final consumer (Commission Regulation (EC) No 589/2008). The operative word is constant, which makes cycling the problem rather than cold itself.
- 04
Why washing changes everything downstream
In general eggs should not be washed or cleaned because such practices can cause damage to the egg shell, which is an effective barrier to bacterial ingress with an array of antimicrobial properties, and Class A eggs should not be washed because of potential damage to physical barriers such as the cuticle, which may favour trans-shell contamination with bacteria and moisture loss, particularly if subsequent drying and storage conditions are not optimal (Commission Regulation (EC) No 589/2008).
- 05
What the cuticle actually does
The cuticle covering the outer surface of an eggshell functions as both a physical and chemical barrier against invading microorganisms, and contamination progresses in four stages: bacterial attachment to the egg surface, penetration through the cuticle and eggshell, multiplication within the underlying membranes, and contamination of the egg contents (Kulshreshtha et al. 2024). Everything both regulations do is aimed at one of those four stages.
- 06
The experimental picture on washing is more mixed
Comparing washed and unwashed white eggs from hens at early, mid and late lay, hen age up to 70 weeks and commercial egg washing did not significantly impact bacterial adherence on eggshell surfaces, and Salmonella Typhimurium was localised adhering to cracks visible on the outer cuticle in ungraded eggs, indicating that pathogens usually enter through respiratory pores or shell micro-cracks (Kulshreshtha et al. 2024).
- 07
Refrigeration is not free either
In a four-week storage comparison, prolonged storage, particularly under refrigeration, led to increased hydroxyl group peak intensities on the eggshell, indicating dehydration and the formation of fissures in the cuticle, while elevated storage temperatures and extended durations adversely affected egg quality (Yu et al. 2025). Both regimes trade something, which is why consistency with the supply chain matters more than picking a side.
- 08
The temperature dose-response behind prompt cooling
In experimentally contaminated egg components, rapid and substantial Salmonella Enteritidis multiplication often occurred at 25 degrees Celsius with 150-cell doses, especially with access to yolk nutrients and after 2 or 3 days, while extensive multiplication was less frequent at 15-cell doses, 1 day of storage, temperatures of 10 to 17.5 degrees Celsius, and when contaminants were introduced into the albumen (Gast and Holt 2000).
What people ask us next.
- Do eggs need to be refrigerated?
- It depends on which system they came from. In the United States the instruction is to buy eggs from a refrigerated case and store them promptly at 40 degrees Fahrenheit or below in their original carton, using them within 3 weeks for best quality (FDA). In the European Union, Class A eggs shall not be chilled in premises where the temperature is artificially maintained below 5 degrees Celsius and should in general not be refrigerated before sale to the final consumer (Commission Regulation (EC) No 589/2008).
- Why does the European Union say not to refrigerate them?
- Because of condensation on eggs whose shell defences are intact. Cold eggs left out at room temperature may become covered in condensation, facilitating the growth of bacteria on the shell and probably their ingression into the egg, so eggs should be stored and transported preferably at a constant temperature and should in general not be refrigerated before sale to the final consumer (Commission Regulation (EC) No 589/2008). The concern is temperature cycling, not low temperature.
- Does washing eggs make them less safe?
- The European regulation argues that it can: eggs should not be washed because such practices can damage the shell, an effective barrier to bacterial ingress with an array of antimicrobial properties, and damage to physical barriers such as the cuticle may favour trans-shell contamination and moisture loss (Commission Regulation (EC) No 589/2008). Experimentally the picture is more mixed, with one study finding commercial egg washing did not significantly impact bacterial adherence on eggshell surfaces (Kulshreshtha et al. 2024).
- Can I move eggs from the counter to the fridge or back?
- Pick one and stay with it. The regulatory concern behind the European position is that cold eggs left at room temperature may become covered in condensation, facilitating bacterial growth on the shell and probably ingression into the egg, which is a statement about moving between conditions (Commission Regulation (EC) No 589/2008). Once eggs are refrigerated, keeping them refrigerated avoids that transition entirely.
- How long do eggs actually keep?
- The American quality window is 3 weeks refrigerated in the original carton, with hard-cooked eggs used within 1 week and cooked egg dishes refrigerated and used within 3 to 4 days (FDA). The relevant risk variable is temperature rather than the calendar: extensive Salmonella Enteritidis multiplication in contaminated egg components was frequent at 25 degrees Celsius over 2 to 3 days and much less frequent at 10 to 17.5 degrees Celsius over 1 day (Gast and Holt 2000).
Every claim, cited.
- [01]US Food and Drug Administration. What You Need to Know About Egg Safety. Buy eggs only if sold from a refrigerator or refrigerated case; open the carton and make sure that the eggs are clean and the shells are not cracked; store promptly in a clean refrigerator at a temperature of 40 degrees Fahrenheit or below and use a refrigerator thermometer to check; store eggs in their original carton and use them within 3 weeks for best quality; use or eat hard-cooked eggs, in the shell or peeled, within 1 week after cooking; refrigerate leftover cooked egg dishes and use within 3 to 4 days, and when refrigerating a large amount of a hot egg-containing leftover, divide it into several shallow containers so it will cool quickly; casseroles and other dishes containing eggs should be cooked to 160 degrees Fahrenheit; cooked eggs and egg dishes may be refrigerated for serving later but should be thoroughly reheated to 165 degrees Fahrenheit before serving; never leave cooked eggs or egg dishes out of the refrigerator for more than 2 hours or for more than 1 hour when temperatures are above 90 degrees Fahrenheit.
- [02]Commission Regulation (EC) No 589/2008 laying down detailed rules for implementing Council Regulation (EC) No 1234/2007 as regards marketing standards for eggs. Article 2(2): Class A eggs shall not be washed or cleaned, before or after grading, except as provided for in Article 3. Article 2(3): Class A eggs shall not be treated for preservation or chilled in premises or plants where the temperature is artificially maintained at less than 5 degrees Celsius; however, eggs which have been kept at a temperature below 5 degrees Celsius during transport for not more than 24 hours or on retail premises or in annexes thereto for not more than 72 hours shall not be considered as chilled. Recital 7: cold eggs left out at room temperature may become covered in condensation, facilitating the growth of bacteria on the shell and probably their ingression into the egg; therefore, eggs should be stored and transported preferably at a constant temperature, and should in general not be refrigerated before sale to the final consumer. Recital 8: in general, eggs should not be washed or cleaned because such practices can cause damage to the egg shell, which is an effective barrier to bacterial ingress with an array of antimicrobial properties; Class A eggs should not be washed because of the potential damage to the physical barriers, such as the cuticle, which can occur during or after washing, and such damage may favour trans-shell contamination with bacteria and moisture loss and thereby increase the risk to consumers, particularly if subsequent drying and storage conditions are not optimal.
- [03]Gast RK, Holt PS. 2000. Influence of the level and location of contamination on the multiplication of Salmonella enteritidis at different storage temperatures in experimentally inoculated eggs. Poult Sci 79(4):559-563. Using experimentally contaminated egg components, the study determined the extent to which small numbers of S. enteritidis could grow to more dangerous levels at different temperatures over a period up to 3 days, simulating the window following oviposition and prior to the achievement of internal temperatures able to prevent further microbial growth. At a relatively warmer incubation temperature of 25 degrees Celsius and with higher inoculum doses of 150 cells, rapid and substantial S. enteritidis multiplication often occurred, especially when the bacteria had an opportunity for access to yolk nutrients and when contaminated eggs were incubated for 2 or 3 days before sampling. Extensive multiplication was less frequently observed at lower inoculum doses of 15 cells, shorter storage times of 1 day, lower temperatures of 10 to 17.5 degrees Celsius, and when contaminants were introduced into the albumen.
- [04]Kulshreshtha G, Ward C, Calvert ND, Benavides-Reyes C, Rodriguez-Navarro AB, Diep T, Hincke MT. 2024. Effect of Egg Washing and Hen Age on Cuticle Quality and Bacterial Adherence in Table Eggs. Microorganisms 12(10):2027. The cuticle covering the outer surface of an eggshell functions as both a physical and chemical barrier against invading microorganisms; contamination of eggs by microbial pathogens progresses in four stages: bacterial attachment to the egg surface, penetration through the cuticle and eggshell, multiplication within the underlying membranes, and the final stage of contaminating the egg contents. Comparing bacterial adherence on washed (graded) and unwashed (ungraded) white eggs from Lohmann laying hens at early (24 to 28 weeks), mid-lay (44 to 48 weeks) and late (66 to 70 weeks) age, the results indicate that hen age up to 70 weeks and commercial egg washing do not significantly impact bacterial adherence on eggshell surfaces. Salmonella typhimurium were localized, adhering to cracks visible on the outer cuticle in ungraded eggs, indicating that egg-associated pathogens usually enter the egg interior either through respiratory pores in eggshells or through shell micro-cracks.
- [05]Yu HC, Chen IC, Tan FJ. 2025. Evaluation of Washing with Sodium Hypochlorite, Ultraviolet Irradiation, and Storage Temperature on Shell Egg Quality During Storage. Foods 14(13):2156. Sodium hypochlorite sanitisation at 150 ppm alone reduced surface bacterial counts by 1.23 log10 CFU/mL, while the combination of sodium hypochlorite and ultraviolet-C irradiation achieved a greater reduction of 1.48 log10 CFU/mL compared with the unwashed group. After two weeks of storage, unwashed egg groups exhibited higher eggshell strength than sanitised groups, though this did not significantly influence internal contamination. Prolonged storage, particularly under refrigeration, led to increased hydroxyl group peak intensities on the eggshell, indicating dehydration and the formation of fissures in the cuticle. Elevated storage temperatures and extended durations adversely affected egg quality, whereas ultraviolet treatment did not have a detrimental impact.
The Larderlab Team builds evidence-led frameworks for eating, lifting, and stocking a kitchen. We cite every claim. We publish the spreadsheet when possible. We buy what we review at retail price. When new data lands, we revise with a dated note.
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