For long term storage I would repackage them in glass with sealed lids. As for just 'how long are they safe to eat', I wouldn't take the expiration too seriously - using your best judgement. Those expiration dates are probably written by lawyers to protect the food companies.
There is speculation about plastic 'leaching' out into food over time, especially wet foods, I imagine. ❓
For long term storage I would repackage them in glass with sealed lids. As for just ‘how long are they safe to eat’, I wouldn’t take the expiration too seriously - using your best judgement. Those expiration dates are probably written by lawyers to protect the food companies.
Having worked in the industry I can tell you that all food and pharma dates are only what has been tested to. Companies will not test out further because: 1) There is no payback for them to do so as vast majority of product is used within that timeframe and 2) They are only required to test what they claim.
So if 90% of their product is off the shelf and used by 3 months they will only test out to 3 times that timeframe (9 months). Then claim the something shorter than the testing (say 6 months) in order to provide themselves a safety margin.
Same thing is true of pharma efficacy - which is why I don’t throw away any unused antibiotics. Just keep them in a cool dry location out of sunlight.