Why You Should Never Put Eggshells Back In The Carton

Food is intrinsically personal, based on personal preferences, culture, socioeconomic backgrounds, ethical considerations, dietary sensitives, and much more. Everyone approaches food and cooking in different ways, some more quirky than others. One oddity that many abide by is returning cracked eggshells to the egg carton. Is this nutritionally sound? Is this an environmental choice? Is it safe? 

Let's not mince words here — don't do it. It's unclear how or why this practice began, but it's not sound. Of course, if you have 2-3 eggs left and you're finishing the carton, feel free to pile up your eggshells in the carton and toss it right out. However, for those who happen to return eggshells to a carton containing fresh, unopened eggs – you may want to rethink that move. 

Mitzi Baum, the CEO of Stop Foodborne Illness, told TODAY that "putting egg shells back in the carton with the remaining eggs and back in the refrigerator is not safe." She notes that it can lead to "cross-contamination and the transfer of potentially hazardous bacteria," which can even result in salmonella. When cracked eggshells are returned to a carton with whole eggs, the un-cracked eggs can also contract the bacteria. 

Can this practice cause illness?

ITODAY also spoke with Kimberly Baker — the director of the Clemson Extension Food Systems and Safety Program Team — who noted that "[salmonella] is often found on the outside of the egg due to passage from the chicken's feces to the egg during the laying process," as well as the fact that salmonella can also be found inside the egg. 

Furthermore, 12 Tomatoes states that returning the shells to the carton is actually a health hazard, noting that the Egg Safety Center states that the practice "greatly increases the risk of bacteria risk by hands, utensils, air, etc." According to Egg Safety, "we would also recommend never reusing egg cartons as they can be a reservoir for bacteria."

Regardless, it's important to dispose of your cracked eggs right after working with them. It's not only peculiar (and unnecessary) to return them to a carton and put it back in the fridge, it's also unsanitary.

What's the final verdict?

Baum actually tells TODAY that "almost 80,000 illnesses and 30 deaths occur each year due to eggs," so it's certainly paramount to properly dispose of those eggshells. You don't return banana peels to your fruit bowl, do you? The entire notion seems kind of contradictory and bizarre, but knowing that this odd practice can also result in illness, it seems pretty clear cut that it should be generally avoided.

Houston Press sagely sums up the practice, noting that "I can't understand why anyone would put trash back into its original container and then store it alongside all the other non-trash food in one's refrigerator." In order to ensure safety for all egg dishes — and all non-egg dishes — it's safest to abandon this peculiar practice and ensure that any cracked shells do not make it back into the refrigerator. Frankly, there's really no reason for them to be there.

It's simple: Dispose or compost cracked eggshells — no ifs, ands, or buts!