You pick up a package of deli meat or a block of cheese and notice that the plastic packaging is swollen and unusually tight. Your first thought may be that it is simply filled with air or that the change happened during shipping. However, swelling can sometimes be a warning sign that gases have been produced inside the package, potentially because of bacterial activity. That is why unusually bloated packaging should be treated with caution.

Gas inside food packaging is not always a sign that something is wrong. Sometimes it is an intentional part of the packaging process, while in other cases it may indicate spoilage. Understanding the difference can help you make safer choices when shopping for food.

For example, bags of potato chips, popcorn, and crackers are often filled with nitrogen rather than ordinary air. Nitrogen is an inert, tasteless gas that helps displace oxygen, slowing the loss of freshness and keeping snacks crisp. The gas also creates a protective cushion that helps prevent delicate foods from being crushed during transportation.

However, swollen packaging on foods that are not intentionally packaged with extra gas can be more concerning, especially if the product is past its expiration date or shows other signs of spoilage. If a package appears unusually bloated, damaged, leaking, or has an unpleasant odor after opening, it is safest not to consume the food. When in doubt, discard it or ask the retailer for guidance.