Thanks for the tip doggiedad, i looked it up, "Avoid large amounts of apple seeds and stems in fresh apples, as they contain cyanogenic glycosides which can cause tummy upset and more serious problems if consumed in large quantities." - See more at: Can Dogs Eat Apples? | Modern Dog magazine
Thankfully this time she stopped and i took it away before she got the stem or seeds, she primarily just ate what was in the photo!
But i defiantly want to start using apple slices in her kong to spice things up. Good to know she likes them, I didn't even think of it.