What's upset my stomach?

[NC2024]

I got a slice of this mail order cake to try and the same day had a really upset stomach, cramps and well, I won't go into detail! Put it down to something I ate

My friend bought me a slice of the same cake from the same place, I had a few mouthfuls of it today. Same again, and I usually have a cast iron stomach

Trying to work out what it is so I can avoid it. No issues with any other cake/large quantities of sugar etc and the other food I've eaten has been different both times

Lactose does that to dh. Maybe the combination of butter/buttermilk/milk chocolate? He also can't eat apples because of the fructose content.

But really you'd have to trial the ingredients individually to work it out for yourself I think.

Buttermilk could be it maybe... I know the local cake shop I usually go to doesn't use it in anything

It's just so weird as I could (for example) down a dominos pizza, 4 cookies and a can of coke and be absolutely fine. Couple of mouthfuls of this and my stomach is wrecked

Maybe one or more of the ingredients was spoiled. If it was mail-order, maybe it wasn't refrigerated properly in transit.

Just weird that it was 2 different slices from 2 different weeks. It's not sent refrigerated as it's fine at room temp