They also tell us that no intruder touched the bowl and that the bowl came from the Ramsey household. And they tell us that JonBenet did not take the bowl out of the fridge/cupboard, as there are no fingerprints of her on that bowl. So it leaves two people as the ones who could take it out and put on the table - Burke and Patsy.
If that was one piece of pineapple she had to eat it very shortly before death. One piece would not last in her digestive tract for hours.
Anyway we don't know the exact amount of the pineapple eaten by JonBenet. As far as I remember it wasn't stated anywhere.
Now, Patsy stated:
Tom Haney: and you'd said earlier you'd cleaned off the table after breakfast?
Patsy: I cleaned off the table.
Tom Haney: so that, that wasn't there.
Patsy: hm-mm. No. I've not seen that.
So, according to Patsy, there was no bowl on the table before they went to the Whites. Either Patsy lied (and had some filthy habits, concerning the food storage) or she told the truth and there was no bowl, because she put it on the table after they'd came back from the Christmas party. There was no pineapple served at Whites so the bowl had to be a source of the pineapple found in the JonBenet's digestive track.
Now, I strongly believe that there was someone else at the Ramseys home that night. Some kind of family friend, so close to them, that they served him tea in the breakfast room, rather informal part of the house, not in the living room. This person was given the hot tea (a beverage nobody in the Ramsey family liked, mind you) with a tea bag still floating in the cup. So our stranger fished it out and put in the nearest empty dish he found - the water glass. I believe he came there to molest JonBenet and it ended up tragically. After she died all the traces of the stranger's presence had to be wiped out, so the cup was probably washed, or stuffed in the dishwasher. The bowl and the water glass were left on the table, forgotten, because Ramseys were too busy with staging, needed to cover up the fact that they willingly allowed their daughter to be sexually abused.