Fun fact Friday: did you know why some countries (like the US) refrigerate eggs but others (like the UK) do not? It has to do with bacteria & how eggs are processed. Salmonella bacteria in particular are a common contaminant of eggs. Eggs are laid through the cloaca, a common cavity for reproduction and digestion (yes, poop comes out the same hole eggs do). As a result, eggs can be contaminated with fecal bacteria during the laying process itself or after laying. Evolution has helped combat this risk to a developing chick (in a fertilized egg): hens secrete a protein during oviposition that forms a protective coating around the shell; the cuticle or the ‘bloom’. Eggshells are porous, so the cuticle coats the egg and seals the pores so bacteria can’t enter the egg and infect & kill the developing embryo. Even if an egg isn’t fertilized, the cuticle is still produced whenever a hen lays an egg. For human consumption, Salmonella contamination is also a concern. Bacteria in or on the egg can make us sick. In the US and elsewhere, eggs are sanitized & pasteurized to kill bacteria on or in eggs. This removes the cuticle, which leaves the shell porous. To prevent future contamination, eggs must be stored in the refrigeration (cold slows microbial growth). This process is regulated in the US: it is federal law that commercial eggs are sanitized and stored in this way. In some countries, eggs are not sanitized prior to being commercially available. The cuticle is left intact, which protects the pores of the eggs (but does not eliminate risk of bacterial contamination). In this case, egg can be stored at room temperature. In many of these countries, hens are vaccinated against Salmonella, which reduces the risk of contamination as well. You can refrigerate them, but once you do, you want to keep them cold; bringing a cold egg out of the fridge can facilitate moisture and microbial growth. What about farm-fresh eggs or eggs from your hens? These typically won’t be sanitized and pasteurized, so theoretically you can store these at room temperature. Either way, ALL eggs that are not pre-washed should be washed just prior to using them to remove any harmful bacteria.