10 Fresh Produce Must-Buys At Costco And 10 To Skip

There are many reasons to love shopping at Costco. The wholesaler lets you stock your kitchen, home bar, and cleaning cabinet with all sorts of household essentials, including an assortment of pantry, fridge, and freezer foods. This membership-only club does this while keeping its prices lower than other retailers by selling items in bulk. Buying large quantities of shelf-stable products, like canned chicken, energy drinks, or protein bars, is a smart buy at Costco. Even some fresh produce will last for months in the pantry or refrigerator, making Costco a great place to buy it as the prices are often lower than you will find elsewhere. 

Some of the big box store's fresh produce, however, should be left on the shelf. It can be delicate, bruise easily, or spoil quickly, resulting in food waste if you cannot finish it before it expires. To help decipher between the worst and the best, I visited my local Costco, checking the store's inventory and assessing the quality of its fresh fruits and vegetables. Armed with that knowledge, here's a list of fresh produce you should buy and what you should skip during your next Costco trip.

Prices are as of the date of publication and may vary based on region.

Home cooks know the importance of having an onion on hand. Adding sliced or diced onions to a dish while cooking elevates the taste, adding a sweet, earthy, nutty flavor to whatever you're making. Knowing this, picking up one of Costco's giant bags of onions may be tempting, especially for the price — less than $1.00 a pound at our Costco location. However, we suggest refraining from the purchase. 

Onions emit ethylene gas, which can cause other fruits and vegetables, like avocados, potatoes, and bananas, to spoil. Therefore, the allium must be stored separately, ideally in a cool, dark, well-ventilated space away from moisture, light, and heat. Moisture causes vegetables to soften, sprout, and begin decaying. While a sprouting onion is safe to eat, its texture and flavor will change, becoming less sweet and crisp as those of a non-sprouting onion, as the vegetable uses stored sugars to produce the sprout. 

If you have a dry root cellar, cool pantry, or basement with constant cool temperatures, you may be able to use the onions before they spoil. However, if not stored properly, you risk wasting a portion of the onions you bought.

Nothing is more flavorful than the taste of a freshly picked, sun-ripened tomato straight from the garden. Tomatoes are a fruit best enjoyed when in season, typically during the warm summer months. 

Nevertheless, Costco sells tomatoes on the vine throughout the year at a cost that is slightly less than the per-pound price at many grocery stores. However, we wish they didn't, as was evident on our recent Costco visit, where we saw multiple boxes of unripened, hothouse-grown vine tomatoes. The fruit lacked the bright ruby-red hue that makes our mouths water, instead looking bruised with a greenish-yellow tinge, indicating the picking and packaging occurred well before beginning to ripen. Tomatoes picked before achieving maturation won't develop their full sweet and juicy flavor — and this won't improve either, even if left to ripen on the counter or windowsill. So it's best to skip the selection.  

The Chinese cabbage bok choy is one of the most nutrient-dense foods you can enjoy. The low-calorie leafy green provides high levels of vitamins C and K, is thought to help reduce cholesterol, and has cancer-fighting properties. The vegetable is interchangeable with fully grown bok choy, containing the same nutritional values, with the baby option tending to be sweeter and more tender. It also has a long shelf life of up to two weeks if adequately kept dry and cool in a refrigerator, which may lead you to want to purchase the membership club's baby bok choy.

However, we suggest skipping the cabbage on your next trip to Costco. Costco's pricing is similar to what you can find at national grocery stores: $6.99 for a 2-pound box. As the best way to maintain freshness is in the crisper drawer, buying the bunches in bulk will take up valuable refrigerator real estate.

Green beans are heart-healthy, low-calorie vegetables. The beans are a star ingredient in the Thanksgiving favorite green bean casserole and are also quickly sauteed with butter to create a delicious accompaniment to any protein. The vegetable's versatility and affordable price of two pounds for under $5.00 may have you considering picking up the package of organic French green beans at Costco. 

However, we suggest skipping the product unless you're prepping your holiday casseroles. Green beans have a short shelf life of only five to seven days after harvest under refrigeration. The beans are also packaged in a sealed plastic bag, where moisture can accumulate, creating a scenario in which mildew can grow, turning the beans slimy. Instead, pick up a bag of Kirkland Signature frozen organic green beans, which can last for months in your freezer.

Buying a pre-cut fresh fruit bowl, like Costco's offering of cantaloupe, honeydew, pineapple, and grapes, seems like a great shortcut. It avoids the mess of breaking down a whole melon or pineapple while saving time and helping you get your daily dose of fruit. Unfortunately, buying and eating a pre-cut fruit package may be risky to your health. Melons are prone to picking up bacteria, like salmonella, in the fields where the fruit grows. 

Washing whole fruit can remove bacteria before cutting the melon. However, there are no firm standards in America for preparing pre-cut fruits, meaning that if bacteria is on the rind when cutting the melon, it will likely be transferred onto the flesh and into the packaging container, spreading to the other fruits in the bowl. Considering the bowl's high price of $11.99 and potential health risk, we recommend buying whole fruit instead.

Eating a mix of leafy greens, like kale, spinach, and collard greens, is a great way to boost your immune system, fight heart disease, and reduce the risk of certain types of cancer. However, you should likely skip the powerhouse greens packed with vitamins and minerals at Costco unless you eat a mixed greens salad every day. Otherwise, there is a high likelihood that the bulk-buy box of organic spring mix or baby spinach will wilt before you finish the container. 

Pre-packaged greens have a shorter use-by date versus buying whole heads of lettuce. Though bacteria can grow on all leafy greens and cause foodborne illnesses, like listeria and E. coli, pre-packaged lettuces undergo more processing during packaging, making them more susceptible. Though these Costco items are well-priced, we suggest skipping the greens.

We suggest avoiding Costco's pre-cut organic celery package. The wholesaler's bagged celery is expensive compared to other grocery stores options. It also comes packaged in a sealed plastic bag, which traps the ethylene gas the vegetable produces inside. The gas will cause the contents to begin to soften and spoil within three or four days from being packaged, which might be the time it took to arrive at Costco. 

Where a whole stalk of celery can last for three to four weeks in the refrigerator, the shelf life of pre-cut, packaged celery is only a few days. While we agree the option is convenient, skip the pre-cut vegetable unless you're making two weeks' worth of gingery green juice at once.

Fresh seasonal berries are the ideal complement to a bowl of yogurt in the morning or a chocolate cake at night. Blueberries, raspberries, strawberries, and blackberries are low in calories and packed with vitamins, fiber, and heart-healthy antioxidants that help prevent heart, kidney, and liver disease. 

With so many health benefits, picking up a container of Costco's fresh berries may be tempting, as the wholesaler stocks the fruit throughout the year. However, berries can bruise easily and are susceptible to mold due to their delicate, porous skin and high moisture and sugar content. Mold spores in the air land on the berries and grow, quickly creating moldy fruit. We saw several Costco berry boxes with juice leaking from the bottom, indicating some of the fruit inside was mush. 

Enjoying slices of bananas on top of a morning bowl of cereal is a great way to start the day. The tree fruit provides essential vitamins and minerals, like vitamin C, potassium, and magnesium, with a sweet, creamy, fruity flavor that kids and adults love. 

The only downside to the tropical fruit is that it continues to ripen after picking, turning from green to yellow to brown within days. Although bananas are one of the least expensive fruits to purchase at Costco, they will likely spoil before you have time to finish the bunch.

Avocados can be expensive. Costco is ready to help by offering a bag of six for under $6.00 at our local store. However, you should skip the avocados at Costco. The downside to buying the fruit at the big box store is that the packaging makes it difficult to assess its contents' ripeness accurately. 

There is a fine line when buying fresh avocados, as the fruit can go from rock-hard and green to becoming black and mushy within days. As you can't hold and inspect each avocado within the mesh bag packaging, it's difficult to know if each option will deliver the desirable creamy, buttery flavor for your morning avocado toast. We suggest buying Costco's pre-packaged fresh, smashed avocado instead.