Eating expired yogurt can be safe or unsafe depending on various factors. Generally, yogurt has a relatively long shelf life, and even if it goes beyond its expiration date, it may still be safe to consume. However, it is important to consider the type of yogurt, storage conditions, and signs of spoilage before deciding to eat expired yogurt.

1. Expiration date: The expiration date on yogurt indicates the manufacturer's estimate of how long the product will remain at its peak quality. It does not necessarily mean the yogurt is unsafe to eat after that date. In fact, many yogurts can still be consumed several days or even weeks after the expiration date, depending on their type and storage conditions.

2. Type of yogurt: Different types of yogurts have different shelf lives. For example, plain yogurt tends to last longer than flavored or fruit yogurts due to the absence of added ingredients that may spoil faster. Greek yogurt, due to its high protein content and strained consistency, also tends to have a longer shelf life compared to regular yogurt.

3. Storage conditions: Proper refrigeration is crucial for maintaining the quality and safety of yogurt. If yogurt is stored at or below the recommended temperature (usually between 35-45°F or 2-7°C), it can stay safe for a longer period. However, if the yogurt has been left out at room temperature for an extended period, it is more likely to spoil and become unsafe to eat.

4. Signs of spoilage: Before consuming expired yogurt, it is important to check for signs of spoilage. These may include an off smell, unusual texture, mold growth, or separation of liquid whey. If any of these signs are present, it is best to discard the yogurt to avoid the risk of foodborne illnesses.

It is worth noting that the above information is a general guideline, and it is always recommended to use your best judgment and follow your senses when deciding whether to consume expired yogurt. If you have any doubts or concerns, it is safer to err on the side of caution and discard the yogurt.

References:

1. U.S. Department of Agriculture: Food Safety and Inspection Service. (2019). Food Product Dating. Retrieved from https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/food-product-dating
2. University of Nebraska-Lincoln Extension. (n.d.). Yogurt: Its Composition, Processing, and Health Benefits. Retrieved from https://food.unl.edu/yogurt