Why should food with bulging packaging not be consumed?

As an editor at a long-established food packaging bag manufacturer, I often encounter questions in my daily work and personal life about why swollen food packaging bags are inedible. Based on my work experience and extensive online research, I have compiled the following information.

1. Let's first analyze the phenomenon of "bulging packaging." Foods that experience "bulging packaging" are definitely sealed packages where the internal pressure is less than or equal to the external atmospheric pressure. "Bulging packaging" indicates that the contents have seriously spoiled, and it also proves that the packaging bag used has good sealing properties. If the packaging bag is not sealed tightly or has a tear, it's normal for the contents to spoil, but "bulging packaging" will absolutely not occur.

   
   

2. Let's investigate the causes of "bulging packaging." Most bacteria or molds that can cause food spoilage (such as lactic acid bacteria, yeast, aerogenes, polymyxa, aspergillus, and hundreds of others) produce large amounts of gas, such as carbon dioxide, hydrogen sulfide, ammonia, and alkanes, during the decomposition of proteins and sugars in food. It is these gases that inflate the packaging bag. During the sterilization process before packaging, microorganisms and buds may not be completely killed. After packaging, these microorganisms multiply rapidly, leading to spoilage and naturally causing the packaging bag to bulge.

3. Which foods are prone to "bloating"? Generally speaking, vacuum-packed meat products are most prone to "bloating" when no preservatives are added, followed by liquid dairy products, and then foods with high levels of animal and vegetable oils. Foods past their expiration date, or those requiring refrigeration but not stored at the required temperature, are also likely to bloat. If you find a packaged food that has been kept at room temperature for a significant period past its expiration date without any signs of spoilage, the reason is obvious: a significant amount of preservatives have been added. As for why meat is more prone to "bloating," firstly, vacuum packaging is the most airtight, with the internal pressure much lower than the external pressure, making the expansion of the packaging most noticeable when gas is generated inside. Secondly, meat and dairy products have a higher chance of being contaminated by spoilage bacteria during processing, and some meat products have complex and heavy structures that are difficult to sterilize completely; for example, whole roasted chicken or duck may have internal cavities that can lead to microbial residue.