When I first started dating my ex, I was at her place and she asked if I was hungry. I said yes, so she made me a tuna melt with mayo. As she had it in the oven I looked in the fridge. The tub of mayo was enormous and mostly empty. It was Kirkland mayonnaise.
I said, "oh, you have a Costco membership?"
"No," she said, "my ex used to."
"The guy you broke up with 2 years ago?"
I looked at the date on the mayonnaise. Expired 5 years earlier. She didn't use it very often.
Not wanting to offend her, hesitantly, I ate the tuna melt. And nothing happened. It was fine.
I had no idea that mayo expired. I had dragged a tub of mayo through several university housing locations and two apartment moves before my new bride noticed the long expired container's date as we combined refrigerators.
I'm not a mayo fan, so was a condiment for guests. Whoops.
This isn't an argument that you should turn into a 'throw away food after the best by date' person or anything, but it's important to understand one key point:
Suppose you have a piece of meat out on the counter for 12 hours. Then you put it in the oven and broil the heck out of it (say the whole thing gets to 190°F and zero of the bacteria in it survive). Is it hazardous?
Yes, it can be hazardous, because the compounds made by the bacteria while they were alive all day can themselves give you food poisoning even after you've sent the bacteria to a firy grave.
Disclaimer/note: I have zero idea about all the various specifics such as whether you're much safer depending if the left-out meat was cooked vs raw, what types of foods are risky or unlikely to harbor harmful bacteria, or how long it is probably safe at what temperature. I have only had food poisoning like 1-2 times, but it was awful so I just try not to do anything too careless.
This is true. The toxins left behind by bacteria or fungi can be worse than ingesting a live culture. And they don't break down by cooking at normal temperatures. I think the only reason 5-year-old industrial mayo is ok is the preservatives. Fresh mayo can kill you after 24 hours unrefrigerated, whether you cook it later or not. Source: Worked in restaurants.
I said, "oh, you have a Costco membership?"
"No," she said, "my ex used to."
"The guy you broke up with 2 years ago?"
I looked at the date on the mayonnaise. Expired 5 years earlier. She didn't use it very often.
Not wanting to offend her, hesitantly, I ate the tuna melt. And nothing happened. It was fine.