There are some precautions you should consider with vacuum sealers. First, it’s important to use vacuum sealer-specific bags. Other plastic bags are porous and allow oxygen to seep in. The second is to know what can and can’t be vacuum sealed. While the short answer for what can be sealed is pretty much everything, there are exceptions. Some foods, like soft cheeses, mushrooms and garlic are vulnerable to bacteria that grows in oxygen-free environments. If you’re vacuum-packing leftovers, make sure the food cools to room temperature, since hot foods can also breed bacteria. And while produce can be vacuum sealed, some cruciferous veggies, like kale, broccoli and bok choy, usually need to be blanched first. Your vacuum sealer should come with a guide regarding specific storage methods.