They're always puffed up with air when I see them in the supermarket. Use the old rule of "If it smells bad, toss it out."

Regarding adding air. No, because the air in the tires heats up as the car is being driven. This is a myth, please google it if you disagree.

I dunno about the car tire thing, but we've had this discussion about inflated/puffed packages of meat here before.

http://ths.gardenweb.com/discussions/2454992/need-quick-help-is-this-chicken-safe

I'm still with the "smell it" camp, and if it smells fine, isn't slimy or otherwise compromised, I'd cook it and eat it.

Annie

Supplier inject CO2 to make meat look pink.

Modified atmosphere packaging (MAP)

dcarch

Sometimes packages puff up from bacteria belches. Even if it's that, however, if it smells fine, it's fine, because you're going to cook it thoroughly anyway.

Thanks, everyone!!!!

Late to this, but 1 thing I do understand is that store packaging for meats is not really airtight, and if you poked a hole in it, it most definitely isn't now.

I always put packages of meats (& frozen fruits & veggies) into another poly zip bag before freezing, for double protection from the air & to protect against accidental punctures.

And I also understand nitrogen may be used in packaging as well. I've seen that printed on the packaing.

FWIW

Modified Atmosphere Packaging (MAP)[edit]

Modified Atmosphere Packaging (MAP) is a technique used for prolonging the shelf-life of fresh or minimally processed foods. In this preservation technique the air surrounding the food in the package is changed to another composition. This way the initial fresh state of the product may be prolonged. It is the shelf-life of perishable products like meat, fish, fruits and vegetables that will be prolonged with MAP since it slows the natural deterioration of the product. MAP is used with various types of products. The mixture of gases in the package depends on the type of product, packaging materials and storage temperature.

Meat, fish and cheese are non-respiring products needing very low gas permeability films and so-called high barrier films are used. The initial flushed gas-mixture will be maintained inside the MA package. Conversely, fruits and vegetables are respiring products where the interaction of the packaging material with the product is important and so low barrier or so-called high permeability films are used for these. So long as the permeability (for O2 and CO2) of the packaging film is adapted to the product's level of respiration, an equilibrium modified atmosphere will be established in the package and the shelf-life of the product will increase.

https://askkaren.custhelp.com/app/answers/detail/a_id/1392/~/do-foods-containing-botulism-have-a-bad-odor-or-taste%3F

Food that contains dangerous toxins does not necessarily taste or smell bad...this is a myth. Experts agree that bulging is not a good sign. When in doubt, throw it out.

The probability of fresh meat being contaminated with botulism spores is very very slim. Of much greater danger is the bottle of oil with the sprig of tarragon.