The Unexpected Extra Benefit Of Buying Your Milk At Costco

In April 2025, the FDA announced a (temporary) suspension of a quality-control program that oversaw the testing of milk, leading to many shoppers nationwide growing concerned about the safety of dairy products. They began to question how retailers ensure their milk is safe from potential pathogens — in 2024, raw milk was recalled in California due to a bird flu risk. Costco, however, is well-known as one of the most trustworthy retailers when it comes to quality, particularly when it comes to milk. As it turns out, the wholesaler has its own special quality standards, ones that far surpass the required bare minimum.

Costco sells many different types of milk. You'll find a variety of milks under the Kirkland Signature brand (everything from organic whole milk to fat-free), but there are also some name-branded milks on the shelves. While the name-brand suppliers are still held to a high standard by the store, the own-brand products actually have to meet a higher standard, further showing why Kirkland Signature is not just a cheap knock-off brand. Costco schedules in-person visits to its milk suppliers and requires minimum human contact with the product to ensure maximum sanitary production. The wholesaler is also extremely diligent about keeping the milk at the most optimal temperature to prevent early spoilage — customers have previously noticed that Costco milk lasts a very long time. Finally, the store also owns an independent lab where it frequently tests select Kirkland Signature products to ensure they're meeting the desired high-quality standards.

Although several grocery chains require certifications and audits from their suppliers, Costco's quality standards are considered to be the highest in the business. All suppliers need to complete an annual unannounced audit from a Costco-approved organization. Costco's own food safety team can participate in the audit and make independent observations. If the audit doesn't meet Costco's quality standards, the wholesaler is notified within 24 hours and holds the right to cancel all orders from the supplier. An unannounced reaudit then takes place within 60 days.

Additional standards apply to suppliers that handle live animals, which is, of course, a key part of dairy farms. They have to meet Costco's animal welfare requirements, which include certifications and audits. The water that the animals drink (as well as the supply used for cleaning) must regularly be tested to ensure no pathogens are present. Other aspects of the food safety requirements cover microbiological testing, the hygiene of the employees, pest control, product traceability, and more. Knowing all of that, it's perhaps not surprising that many people have their Costco membership on auto-renew.