Why you should think twice before buying the mayonnaise at Costco

How much mayonnaise is too much? For many, the one-gallon jars of mayonnaise sold at Costco max out their mayo quota. While Costco employees have varying opinions on products they'll never take home from work, big jars mayonnaise are definitely on the list (via Business Insider).

Eat This, Not That! includes condiments in their round-up of foods to avoid buying in bulk from Costco. Despite being loaded with preservatives, including salt, sugar, and acid (like vinegar and lemon juice) in mayo's case, condiments can and do still go bad.

Once you crack open a big ol' jar of mayonnaise from Costco, the clock is ticking. Taste of Home gives you two months to get to the bottom. This is the USDA recommendation as well. Though Kraft says that opened, refrigerated mayonnaise can last a bit longer: three to four months. Each brand has different acidity levels which may account for the disparity in best buy dates (via Shelf Life Advice). When in doubt, throw it out.

Bulk mayo is a bad idea

Unless you really really love mayonnaise, buying this condiment in bulk may be a bad idea. A typical serving size of mayo is 1 tablespoon (via MyFoodDiary). That's about the right amount to slather on a BLT, or tomato sandwich. Converted to gallons, that's a whopping 256 servings per gallon jar. That boils down to 128 servings per month on a two-month timeline!

If you do end up with a dubiously-large amount of mayonnaise, don't despair. Mayonnaise is one of America's favorite condiments, after all (via US Weekly). That means there are endless recipes for dealing with a mayo glut — from dreamy, creamy artichoke dip, to a whole lot of mayonnaise-dressed salads (potato, tuna, chicken, and coleslaw, to name a few). HuffPost may just inspire you with their celebration of mayonnaise-forward recipes. 

Still, with that much mayonnaise on-hand, you may need to think outside of the box. Why not try adding it to dessert? Mayonnaise is actually, believe it or not, a long-treasured secret ingredient for an extra-moist cake. Better yet, a traditional (and decadently-delicious) chocolate mayonnaise cake calls for a whole cup of this creamy condiment per batch.