As if to prove the point I've just been poisoned (sore stomach) by some Heinz (Jewish brand) salad cream. I have not bought salad cream for about a year now due to a previous poisoning from it and it just shows the logistical lengths they go to, to catch me out, putting poisoned salad cream on the shelves, each time I head to the shops in the off chance I might buy it, then taking it off again if I don't so no one else gets poisoned!
If it wasn't the salad cream, then it was the sausage that I put the salad cream on because that's all I've had today. The previous pack of sausages purchased at the same time were OK, which is why (at the moment) I'm blaming the salad cream. This kind of sore stomach poison (in my vast experience) seems to exist only in dairy products, milk, cheese yogurt etc. I believe salad cream is in that category.
It is NOT an allergy (to dairy products) if I taste test the cheese, milk or whatever and it's safe, I can consume it with no ill effects. Indeed with cheese, it used to open it along the long part of the oblong, now it opens (and reseals) on the top or short part of the oblong, so when I opened it, tested it and it was ok, so thinking it's safe I ate it safely down to the bottom quarter, which was poisoned. Extremely sneaky but now I test ALL cheese before consumption, wish I'd tested the salad cream.