MSG is one here. Only found out after giving DD2 theatre pop corn, rather than mocrowave stuff.
Yellow is the worst colouring for my kids. Purple also sets DD2 off (the gp office gave her 2 lollipops & I paid for it for hours!)
I pretty much avoid anything sugary that might have colours. Cordial, juice (I occasionally buy apple, but I have to watch the brand )
I can't give DD2 'chemists own' iburofen coz its orange. It literally gets her bouncing off the walls!
I don't buy grapes often & rarely buy strawberries, so I have no idea how they'd go. The few times we've had them we've been ok, but then, DD2 doesn't eat them
Oh, & chocolate! Also depends how its eaten. Easter eggs seemed ok, but cocolate muffins yesterday had them going. So it may have been something else in the muffin, but other flavours are fine.
We are pretty much trial & error still.