You are watching: How long can mayonnaise stay out
Of all the anxieties surrounding taking occupational to lunch—and there are plenty, from what to bring said having lunch in, to making sure claimed lunch isn't stolen—perhaps none is together nagging together the anxiety approximately mayonnaise.
In short, human being seem encouraged that, if left in ~ room temperature for even a short duration of time, the mayonnaise on your sandwich will certainly sprout every sorts of bacterial growths—growths the will cause illness, gaue won ruin, and also all sorts of various other tragedies.
A seminal examine from 2000 took a look in ~ the fragility that mayonnaise and set the record straight: "Salmonella, E. Coli O157:H7, E. Coli, L. Monocytogenes, Staphylococcus aureus, and Yersinia enterocolitica die once inoculated right into mayonnaise and also dressings."
To placed it just as plainly, but in layman's terms, store-bought mayonnaise includes enough acid (from vinegar or lemon juice) to not just kill food-borne pathogens, but also to avoid them native forming.
What this means is that the angst around an egg salad sandwich—that is, the are afraid of letting the sandwich sit the end for an hour or two at room temperature because the mayo can spoil—is in reality backwards. If anything, the mayonnaise is preventing microbial growth. The egg (and turkey, and also sliced ham) would certainly be an ext dangerous without it.
Karen, the government's cartoon food safety skilled (yes, you review that correctly), concurs with the outcomes of the study. Human being often finger mayonnaise together the culprit because that food-borne illness, yet according come Karen, "usually it's the meat, poultry, fish or eggs in a sandwich kept out that the frozen fridge for an ext than two hrs that is the medium for bacteria come grow." (For a cartoon, Karen is really quite informed around these things.)
Some vital notes: This is only true through commercially-made, store-bought mayonnaise. Homemade mayonnaise, which provides raw eggs, is a various matter altogether, and also should be retained cold. And because other components of a sandwich are susceptible come spoilage, your lunch should most likely not sit out at room temp—and definitely not in the sunlight (on, say, the beach)—for hours and also hours top top end.
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But when it comes to your commute, or leaving a sandwich top top your workdesk for an hour or two, you have the right to relax. Focus on other lunch anxieties instead, choose who stole your dessert indigenous the fridge.