How Long Do Dairy Products Last in the Refrigerator?

How long an opened dairy product lasts in the refrigerator depends on its water content and live cultures. Consuming opened milk within 5–7 days, yogurt within 1–2 weeks, and ayran within 3–4 days is recommended; higher-fat products such as clotted cream and cream may last a little longer. These periods are counted from opening, not from the production date. They apply when the product is tightly closed and stored in a part of the refrigerator below 4°C / 39°F; storage in a temperature-fluctuating area such as the door shortens the time. Keep dairy on a cold, stable lower shelf, away from the door.

How Can You Tell If Milk Has Spoiled?

Spoiled milk may first develop a slightly sour smell, followed by curdling. If heated, it may separate and form curds, another clear spoilage sign. The clumps form when milk protein reacts with acid and cannot be reversed by stirring. Color change is usually a later sign, so appearance alone can be misleading. Spoiled dairy products can cause food poisoning, so discard the product if its smell or texture has changed suspiciously.

Why Does Yogurt Last Longer Than Milk?

Live bacterial cultures make yogurt acidic, and this acidic environment slows the growth of harmful bacteria. That is why yogurt may last longer after opening than milk. Yogurt's cultures compete with other microorganisms, and unopened yogurt stays safe longer than unopened milk. A yellowish layer of liquid on top is whey, not spoilage, and can be stirred in and eaten. Whey is a sign that yogurt contains live cultures and has not been excessively concentrated industrially.

Why Should Ayran and Kefir Be Used Sooner?

Ayran is diluted yogurt and is less concentrated, which can make it easier for bacteria to grow. Ayran should be consumed within a few days after opening. The more it is diluted, the faster it may spoil; homemade, watery ayran may have a shorter storage time than packaged ayran. Kefir contains live cultures and continues fermenting, so it may naturally become more sour and fizzy over time, even in the refrigerator. This is continued fermentation rather than spoilage, and a slightly swollen lid may also result from natural gas production.

How Do Clotted Cream and Cream Differ?

Higher-fat dairy products such as clotted cream and cream have less water and are described as less favorable to bacterial growth, so they may generally last 7–10 days without spoiling. This longer shelf life is due to fat limiting the water needed for bacterial growth. These products can absorb odors, so store them in a covered container away from strongly scented foods. Clotted cream left uncovered may absorb the smell of nearby onions or spices within a few hours.