Skip to content

18 Worst Foods to Buy in Bulk at Costco

Yes, the warehouse is full of great deals. But that doesn't mean you should buy everything on display.
Costco avocados bulk

Costco is one of America's most beloved stores, and for good reason. Where else can you make a whole meal out of free samples, purchase a diamond ring, and buy a rotisserie chicken for just $5?

Mainly, Costco is known for its bulk items: vats of mayonnaise, gallons of olive oil, a 16-pack of tuna cans. But as much as people love shopping at this members-only store, you shouldn't buy everything in bulk. Even if you think you're saving money at the moment—after all, those low prices can be pretty enticing—you're actually losing it in the long run.

That's because a lot of those bulk foods go uneaten and wind up being thrown away. A study in the International Journal of Consumer Studies found that low-income households waste more food than middle-income homes, due in part to bulk buying. It typically goes like this: We see something that's a better value when bought in bulk, we get bored stiff of it and by the time we can stomach the idea of digging back into the pile, it's either gone bad or lost its flavor or nutritional potency.

Make sure you avoid these common items bought in bulk—not every low price is a truly good deal.

1

Avocados

Bulk box avocados
Shutterstock

An entire bag of avocados for under $5? How could you pass up that deal? We'll tell you. Unless you're buying a bag of avocados to make guacamole for a party, it's probably not worth buying the fatty fruit in bulk. If you buy avocados in bulk, they could all ripen on the same day, leaving you with half a dozen fruits to get through before they go bad! If you still want to buy in bulk to save money, you can store avocados in the refrigerator to slow down the ripening process. It's just one of the 30 Simple Tricks to Make Your Produce Last Longer.

2

Nuts and Seeds

Bowl of nuts
Shutterstock

Nuts seem like one of those foods that never go bad, but that's actually not the case. Even if they don't grow mold or get freezer burn, they can still spoil. Both seeds and nuts contain a lot of oil, which comes from healthy unsaturated fats. The problem is that fats tend to go rancid rather quickly. Even if you store your seeds and nuts in an airtight container and keep them in a cool, dark spot (as you should), they'll only keep for a couple of months. If you're stuck with a mountain of macadamias or a hefty bag of hazelnuts, put them in airtight containers and store them in the fridge or freezer. This may extend their life to up to a year.

Looking for ways to use up those nuts? Try these Four Different Spice Roasted Nut Recipes Ideal for Snacking.

3

Spices

spices in jars
Shutterstock

Even if spices don't actually go bad, they do go stale rather quickly. (Psst: You're Definitely Not Replacing Your Spices Often Enough.) That's a huge bummer because the whole point of spices is to, you know, be flavorful. The more refined the spice, the more rapidly it will lose potency. Ground spices will start to get dull after just six months, while spices purchased in a whole form—cumin seeds for example—have about a year. Although buying in bulk seems tempting for the price, people typically only use a pinch here and there, so buying large amounts isn't necessary. They'll go bad before you get to enjoy them all.

4

Flour

Flour and Rolling pin
Shutterstock

Flour, be it all-purpose, whole wheat, or another variety, attracts water. Although that makes it a great ingredient for thickening soups, stews, and sauces, it also means it soaks up moisture in the air. And the longer you have it, the more time it has to soak up moisture, and the closer it is to turning rancid. White all-purpose flour actually keeps longer than whole grain or nut flour—about a year versus a couple of months—but unless you are cooking and baking with flour every day, you probably won't go through a bulk size within the year. You can extend the life of flour by putting it in your fridge, but if you keep buying everything on this list in bulk, your icebox is going to get pretty crowded. And if you're looking for an alternative to white flour, try one of these 20 Flour Substitutes For When You've Run Of All-Purpose Flour.

5

Coffee

Coffee beans with metal scoop
Shutterstock

Coffee is pretty cheap as it is, so there's no real need to buy it in bulk. Plus, real coffee aficionados know that's not the freshest way to enjoy a hot cup of joe. The freshest, best tasting cup of coffee is made from beans that have been roasted within two weeks of the cup being brought to your lips. If you value what your coffee tastes like you're best off doing two things: Choose a bag that contains as much coffee as you could get through in a week (or two), and avoid those giant barrels or bins of coffee altogether. You don't know how long the coffee's aroma and flavor have been sucked out of the beans and into the surrounding air.

More on Costco

  • costco

    Costco Just Made This Major Change to Senior Shopping Hours

    A new schedule is coming soon.
  • costco samples

    How You Can Stay Safe While Enjoying This Costco Favorite

    Why this super popular benefit of shopping at Costco could be dangerous.
  • Various cakes for sale at Costco Wholesale.

    Costco Just Discontinued This Beloved Food

    Say it ain't so, Costco!
  • 5 Foods Suddenly Selling Out at Costco

    5 Foods Suddenly Selling Out at Costco

    Depending on where you live, these may be out of stock.
  • costco membership

    Mistakes Shoppers Are Making at Costco

    Here is what we've seen so you know what not to do.
6

Whole Grains

Holding brown rice in hand over a glass bowl of rice
Shutterstock

Did you realize whole grains contain oils? They're found in the grain's bran and germ and can cause them to go rancid quickly, just like nuts and seeds. Although the oils are removed during the processing of grains like white rice, they remain attached to the grain and can cause them to go bad.

7

Condiments

Mayo
Shutterstock

Your favorite condiments like ketchup, mayo, and mustard tend to be loaded with sugar, salt, and other preservatives. Despite this, they can still go bad. Even if they are "shelf-stable," they are slowly going bad. Family finance and frugal living expert Jordan Page advises you forgo buying an economy-sized vat of ketchup. "It almost always will go bad before you can go through it," she says.

8

Jerky

beef jerky
Shutterstock

Because beef jerky is preserved with salt and other spices, you'd think it would stay fresh for a long time, right? Not quite. The meat snack, whether it be chicken, beef, or turkey, needs to be refrigerated after opening. In fact, most jerky packages state to eat within three days of opening and store it in the fridge after that. But even in the refrigerator, jerky only lasts about a week or two. Unless you want to get fancy and vacuum seal it (in which case it can last up to two months), you're better off sticking to the smaller packs.

RELATED: The easy way to make healthier comfort foods.

9

Oil

castor oil in glass jars
Shutterstock

Even if you're someone who frequently cooks with oil and uses it as a base for sauces and dressings, it's unlikely you'll go through one of the bulk-sized vats in the three to six-month timeframe that experts recommended you enjoy oil once it's opened. And it doesn't matter which type of oil you use: Olive, sesame, canola, and peanut all start to go rancid at around a few months, even when unopened. Once a bottle is open, it only lasts between one and three months. According to Bertolli, Americans only go through about one and a half 750-milliliter bottles of extra virgin olive oil a year, so you likely won't have to buy that much oil.

10

Fresh Produce

raw yellow fingerling potatoes in bowl
Shutterstock

Yes, Costco has incredible deals on fresh foods like potatoes. But if you don't have a big household, you probably won't get to use all of them before they start going bad.

11

Shredded Cheese

Shredded cheese
Shutterstock

Even if you eat a quesadilla at every meal, you probably won't get through Costco's giant bags of cheese before their expiration dates.

12

Milk

gallons of milk at costco
Shutterstock

Aside from the fact that you probably won't finish a giant container of milk in time, Costco's milk jugs are really hard to pour. Try buying almond or soy milk at Costco instead—the cartons are sold in multipacks, so you can use each one individually without worrying about the rest of it going bad.

13

Butter

sticks of butter stacked on top of a wooden board next to a knife
Shutterstock

Costco's organic butter is a great deal for holiday baking and other times when you'll need a lot of butter at once. But for the majority of the year, you won't need that much butter at one time. Ever.

14

Hummus

Creamy homemade hummus
Shutterstock

Unless you're throwing a party, you don't need as much hummus as a Costco-sized tub will give you. Stick to a smaller portion from a traditional grocery store to prevent food waste.

15

Eggs

cartons of costco eggs
Shutterstock

Aside from the fact that you probably won't use more than a dozen eggs before they expire, Costco's egg prices aren't that much better than what you'd find at a competitor.

16

Cereal

cereal aisle at costco
David Tonelson/Shutterstock

Yes, the bags of cereal are individually wrapped at Costco, so they won't go stale despite the larger box. But do you really need to lug that much cereal home? Costco's cereal prices aren't much cheaper than what you'd find at a local grocery store, so you might be better off buying the smaller boxes.

17

Fresh Bakery Items

trays of costco chocolate chip cookies
Shutterstock

Sure, that $18 cookie tray was great for holiday parties. But will your family really eat all of the cookies or pastries in a Costco-sized box on a regular week? You're better off buying a smaller portion of these treats at a regular grocery store.

18

Baking Powder & Yeast

nutritional yeast vegan cheese
Shutterstock

While baking soda can last for a long time, baking powder is prone to attracting moisture—the same reason why flour goes rancid. Unless you are baking up a storm every day, it's unlikely that you'll go through your big tub of baking powder before it goes bad. Baking powder can only stay fresh and active for about six months to a year when stored in a cool, dry place. Dried yeast may still do the trick after six months, but the fresh variety will lose its mojo months sooner. Store fresh yeast in the fridge and dry yeast in the freezer for maximum shelf life.

She Lost 100 Pounds—And Shows You How!

Registered Dietitian and Nutritionist Ilana Muhlstein lost her weight and kept it off—and in You Can Drop It!, she'll show you how to lose it, too. More than 240,000 clients have chosen her program—and now it’s yours to keep.