I had cheddar cheese go moldy on me, but it never became rancid, and I had kept it in the fridge for over a month. Was it past its best by/ sales expiration date? If it goes moldy, I just remove the mold and carry on.
Somehow a situation had to develop where the contents were contaminated with bacteria, but there wasn’t enough air for mold to compete (and the package was airtight enough to bloat). Which is strange because I would have thought sterilization was done post-packaging. Maybe a random package that simply didn’t get heated enough?
I keep cheese in the fridge, but i sometimes keep it for months. Sometimes it goes moldy. I’ve never had it go rancid. Cheddar keeps well. I but agreed chat that’s been intentionally aged for more than a year somewhat often.
I’ve never bought that sargento. I’m guessing it’s not real cheddar. But maybe something about slicing it exposed so much of it to air that it goes bad.
In the special highly artificial situation of improperly canned food where it was sterilized almost enough: enough to kill all competing microorganisms that would cause a giveaway bad taste and smell, but not enough to kill the slower-growing but extra-hardy botulinum microbe. It took the invention of canning to contrive a circumstance that could fool our bad-food warning instincts like that.
It is entirely possible that it left the packaging factory completely intact but somewhere between that point and its arrival on the store shelf it was pierced/punctured/otherwise contaminated. It happens sometimes. Sometimes we catch it in the backroom before it hits the shelf. Sometimes we don’t.
Could be a staple, a nail, the point of a boxcutter opening a cardboard shipping box…
Hard to say exactly what happened but yeah, sometimes things go wrong and food goes bad.
“Plastic” is a bit harsh, but it is basically milk that’s been separated into its component molecules and then recombined. Kraft singles don’t even qualify for the relatively prestigious “pasteurized process cheese” label due to added milk protein concentrate. That seems to have been a (longstanding) tariff avoidance measure.