Are air bubbles/pockets/loose casing in raw sausages okay food safety-wise? I don't know if it's just because they didn't fill them as full or if they formed from gases/bacteria. They are five days before the best before date Merguez sausages. Thanks!

3 Answers 3


It is most likely just a void. It is hard to pack a casing 100%. There will be voids.

Could it be (toxic) bacterial gas? Maybe but not likely.

  • 1
    Remember your going to cook them. Cooking not only changes the flavor of the meat but kills off almost all harmful bacteria. Air pockets, will get cooked to, and will usually "pop", but even if they don't any bacteria in the air pocket will be killed off.
    – coteyr
    Sep 28, 2016 at 7:22
  • 14
    @coteyr Any bacteria in the air pocket may be killed off yes, but the toxins they leave behind can not be cooked off.
    – James T
    Sep 28, 2016 at 7:30
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    True, if your meat is old enough to have toxins then best to throw it out. Usually though this is only really a problem, if the meat is stored at room temperature or stored (in the fridge) for a really long time. Standard meet rules apply. Once thawed cook it, don't let it set in the fridge raw for more then a day or two.
    – coteyr
    Sep 28, 2016 at 7:33
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    As far as I know, bacterial toxins are not usually gaseous. There are spores etc. that can be carried in gas, but they can also be carried in (e.g.) sausage.
    – abligh
    Sep 28, 2016 at 9:02

To avoid it, you'd need to pack them in a way that makes them more like hot dogs than sausages. Hot dogs are a smooth emulsion of (usually) reclaimed meat, fat and spices. Sausages are mince that's been somewhat loosely packed and cooked (usually smoked) in a casing along with herbs, fat and spices.

With synthetic casings, you can pump a bit more pressure resulting in a denser sausage with less air, but there's still going to be some. However, the hallmark of a great quality sausage is a natural casing, with little nooks of air, fat, spices, etc.

What you have sounds like quality sausage in a natural casing, and you should positively consume it when it's fresh (ideally within days of buying it!). But there's nothing wrong with leaving them out in the back of the fridge to age a little bit (really helps bring out the flavor of fennel / anise) prior to cooking them up, and they will be a little loose and crumbly.

If you pick up on even a slight acrid taste or smell, don't use them. Otherwise, you're fine.

  • * Sausages are cooked mince* -- they're not cooked when they're packed into the casings
    – Chris H
    Sep 28, 2016 at 7:45
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    @ChrisH Yeah that doesn't quite read well and as intended, fixed.
    – user293
    Sep 28, 2016 at 7:54
  • As far as I'm aware, air in sausage is always a fault, even in 'great quality sausage'. In smoked sausage it's not too bad, but can lead to a 'crumbly' product. In fresh sausage, it's annoying because when cooking, 'windows' of air can dry out and crack more easily. In dry-cured sausage, it's especially bad because when aging the oxygen can turn the fat rancid and bad mold/bacteria can grow in the void. Commercial stuffers include vacuum pumps to remove trapped air in order to improve quality and consistency.
    – Nick T
    May 31, 2022 at 16:17
  • @NickT In dry-cure it's absolutely dangerous. I rather like the crumbly nature of certain kinds of bangers, for instance. I think for brands consistency is paramount because of so many varying tastes. I wouldn't call it a fault in most cases unless it was excessive, but that's just me.
    – user293
    May 31, 2022 at 20:34

The casing on a fresh sausage needs to be left somewhat loose because the casing will contract when it's cooked. If it were stuffed as tightly as possible, it would be almost certain to split open in the frying pan. Even for a sausage that will be poached first (boudin blanc, e.g.), which causes the casing to shrink much more gently, you must account for that shrinking.

Air bubbles are simply a natural consequence, as Tim Post says, of the size of the grind. You notice that tennis balls in their can also have "air bubbles" around them. If there are a lot of bubbles, it's a sign of perhaps not-quite-painstaking manufacture: usually the bubbles are pierced after the links are formed. This is again to prevent splitting: the air will expand when it's heated and that can rupture the casing.

The pockets are not a danger sign by any means, though. The only worrisome hypothetical I can think of would be that they appear to inflate on their own while the sausage is in cold storage: that means something alive is producing gas. (My guess would be that'd just be harmless yeast, but) When in doubt, throw it out.

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