Almost instant food poisoning? Had to be...but how?

Well, it smelled good after I stuck it in the microwave and I didn’t notice the small amount of mold until afterwards. It did taste strange at the first bite, but I had topped the dog with mustard, relish and onions. I was visiting my father’s house and thought it was the generic brand mustard that tasted bad. It was during the second bite that it really tasted bad, but I swallowed anyway. I figured, hey, cheap mustard ain’t going to hurt me. Just a few seconds later it felt like someone punched me in the gut.

I was once at a conference and had breakfast in the hotel’s restaurant. Waffles and sausage. After eating, I sat down for the symposium and five minutes into it, became horribly and violently ill. I was so sick I wished for death.

There are a lot of vague terms being bandied about in this thread. I have had a violent reaction to spoiled food in as little as 15 minutes. If “having a violent reaction to spoiled food” works as a definition of “food poisoning,” as I suggest it does, then there are some terms to be defined and agreed upon in this discussion.

What the hell is an Esky?

An “ice box”.

OK, that’s the name my grandmother used for a refrigerator.

But unless it was unplugged or otherwise not working, how would 6 hours of refrigeration let food get spoiled?

It’s not a refrigerator, it’s a simple insulated box that will keep food or drinks cool for a while. Esky - Wikipedia

In a previous life I would’ve called it a “chilli bin”.

As I have, most unfortunately, discovered on four occasions (involving, in order, shrimp, swordfish, tuna, and a Caesar dressing with anchovies), there is actually one type of fish- and seafood-related food poisoning where symptoms can start to appear as early as 5 minutes after consumption: acute histamine toxicity. Evidently, it’s often confused with seafood allergies, but the most common cause – and what felled me each time – is inadequate refrigeration or spoiled fish.

Six years later, the OP is still puking.