What Causes Red Colored Stool In Children?

My 14 month old has had diarrhea since yesterday afternoon. It started out normal in color and remained that way until around 3 hrs ago. I changed her and it was pinkish red in color but doesn t look like blood. She went to a birthday party for her 1yr old cousin the weekend & the day after the party that cousin began having diarrhea that lasted 2 days but drs said it was teething. My lil girl has almost all of her teeth except for a couple in between the back and front. Her diet hasn t changed, she eats balance of fruit veggies meat & grains. She drinks whole milk & water sometime flavored with sugar free flavor packets (this week flavor cherry) & at night she has a cup of milk with carnations breakfast essentials powder mixed in sometimes strawberry, chocolate, or vanilla. She has been acting normal, playing, eating & drinking as usual. I have had upset stomach yesterday but went away after a few hours, a child at the party had recently gotten over a stomach virus about 1 week prior to the party. Is this color something I should be concerned about? She does have red based food in her normal diet & we have switched from the grape flavor packets for water to the cherry just a couple days ago so I m not sure if this is contributing to it. She has no other symptoms & doesn t appear sick on any way other than the diarrhea which isn t extremely bad, just 4 times a day & normally her normal stool is twice a day so she s only going 2 times more than usually and it isn t extremely watery, it kinda looks like the consistency of a bf baby switching over to formula type consistency. Any advice is greatly appreciated!!!