Shoppers have noticed that Kirkland-brand milk from Costco often stays fresh well past its expiration date, sometimes up to a week after. A resurfaced Reddit thread highlights customers' surprise and satisfaction with the milk's longevity.
Experts attribute this to Costco's stringent quality controls, which exceed federal requirements. While US law mandates Grade A milk to have fewer than 100,000 colony-forming units of bacteria and be chilled to under 45°F within two hours of milking, Costco imposes stricter standards on its suppliers.
According to Costco's 2023 Food Safety & Quality Audit Expectations, each facility producing Kirkland milk undergoes at least one unannounced audit annually, with two in China. Scores below 85% lead to severe consequences. Every batch is tested with roughly 60 microbial tests; a single failure can halt shipment.
Water used in processing is strictly monitored, with quarterly testing of private wells and rotating lead auditors to prevent complacency. Milk from healthier herds, measured by lower somatic cell counts, lasts longer. Herds averaging under 200,000 cells/mL are considered top-tier, while those above 400,000 cells/mL spoil faster.
These measures result in less food waste and fewer shopping trips for customers. The Independent has contacted Costco for comment.
