Can Yogurt Sit Out Overnight?

The 2-hour rule for yogurt

The USDA recommends discarding all perishable dairy — including yogurt — left at room temperature for more than 2 hours. At temperatures above 90°F (32°C), the limit drops to 1 hour. Yogurt is a cultured milk product with a high moisture content, and while beneficial bacteria are present, harmful bacteria can also multiply at room temperature. See the official food-safety sources used by StillSafeFood for references.

Does yogurt's acidity protect it?

Yogurt is naturally acidic due to lactic acid produced during fermentation. This acidity does slow the growth of some harmful bacteria compared to plain milk — but it does not prevent bacterial growth at room temperature. Pathogens such as Listeria monocytogenes can survive in acidic environments and grow at temperatures above 40°F. The USDA 2-hour rule applies to yogurt the same as to other perishable dairy products.

Safe yogurt storage

• Keep yogurt refrigerated at or below 40°F (4°C) at all times until serving.
• Return yogurt to the fridge within 2 hours of taking it out (1 hour above 90°F).
• Keep the container sealed when not in use to prevent contamination.
• Consume opened yogurt within 1–2 weeks of opening, per the sell-by date.