1. Kirkland Signature Solid White Albacore Tuna
If your concern for animals extends to the ocean, you may want to skip Costco's inhouse Solid White Albacore canned tuna.
In 2017, the environmental organization Greenpeace ranked the product as one of the nine worst cans of tuna on a "shopping guide" for "sustainable, ethical, and fair" tuna brands. In its ranking, Greenpeace criticized Costco's tuna sourcing in part for failing to "address destructive fishing practices."
Alternatively, you can buy Wild Planet tuna at Costco, which Greenpeace found to be the most sustainably-sourced brand.
2. Kirkland Signature Laundry Detergents
Kirkland Signature offers several varieties of environmentally-conscious laundry detergents, like the Kirkland Signature Environmentally Responsible Liquid Laundry Detergent, and the allergy-free Kirkland Signature Free & Clear Liquid Laundry Detergent.
Despite the detergent’s name, The Environmental Working Group has given Kirkland's "Environmentally Responsible" liquid laundry detergent an F-grade for environmental friendliness, citing risks of asthma, skin irritation, cancer, and harm to the environment.
Some customers on Consumer Reports also reported getting rashes after using Kirkland’s Free & Clear Liquid Laundry Detergent.
3. Kirkland Signature Supreme Diapers
If you're a new parent, buying diapers in bulk might sound like the way to go. But Kirkland's Signature Supreme Diapers may not be your most efficient option.
The smallest quantity of diapers that the Kirkland brand sells in size 1 for infants is 192 diapers. As the deals site Cheapism notes, your baby could outgrow these 192 diapers before you can use them up.
4. Kirkland Signature Light Beer
Kirkland vodka gets high ratings, even when compared to name brand competitors, and Kirkland branded wines have developed a loyal following. So, you might think that good Kirkland beer is a no-brainer.
However, when it comes to Kirkland Signature Light Beer, you'd be wrong, at least according to aggregated online reviews. Customer reviews on RateBeer complained about the light beer's taste, with one reviewer saying it smelled like "urine." RateBeer users gave the beer a score of 1.97 out of 5, while BeerAdvocate reviewers gave it a 2.5 out of 5.
Kirkland's light beer does have its fans, though, not least because it costs less than 50 cents a can. One customer and superfan, Randy Colpek, even went viral on YouTube in 2017 with a homemade commercial for his drink of choice, Kirkland Signature Light Beer.
5. Anything you can't finish before it goes bad
The Kirkland brand has a lot of great products, but most come in supersized "bulk" containers. If you can't use an item up before it spoils, it may not be a valuable purchase, no matter its quality.
In addition to items that go bad quickly, like milk or cheese, use caution when you buy longer-lasting foods, such as oils, grains, and spices, which do still expire. For instance, Southern Living recommends using olive oil within 18 to 24 months to keep it from going rancid.
Grains, such as rice and quinoa, can go bad too, with time. The Whole Grain Council advises that whole grains will last for six months on "a cool, dry pantry shelf" or "up to a year in the freezer."
