You pick up a package of deli meat or a block of cheese and notice that the plastic wrapping is swollen and stretched tight. At first, it may seem like the package simply trapped extra air during shipping. In some cases, however, a bloated package can indicate that gases have formed inside, possibly as a result of bacterial growth. For that reason, unusually swollen food packaging should be approached with caution.

Not all gas-filled packaging is a sign of spoilage. Many foods are intentionally packaged with protective gases to help preserve freshness and extend shelf life. Understanding why some packages contain gas while others should not can help you make better decisions when buying groceries.

For example, bags of potato chips, popcorn, and crackers are commonly filled with nitrogen instead of ordinary air. Nitrogen is a harmless, odorless gas that replaces oxygen, helping slow the staling process and keeping foods crisp for longer. It also acts as a cushion, protecting delicate snacks from being crushed during transportation and handling.

On the other hand, swollen packaging on foods that are not designed to contain extra gas can be a warning sign, especially if the product is expired or shows other signs of spoilage. If a package appears unusually bloated, damaged, leaking, or produces an unpleasant odor when opened, it is safest not to eat the food. When there is any doubt about its condition, discard the product or seek advice from the retailer.