I bought some fruit from my local market the other day - same stall I've always used. Gave my DD some strawberries (which she normally wolfs down), and she said "yuck". So I took one, put it in my mouth and was about to do the usual "mmm mummy likes them"...but she was correct. They were in fact "yuck!". They tasted very metallic and gross. I always wash fruit before I serve it to my DD, so I'm sure it was the fruit itself that was minging, not something on the surface. Ever since she ate a couple of those strawberries, she's had foul, explosive, liquid diarrhoea
She's otherwise healthy. No temperature, no vomiting etc. The only other thing that's weird, is that she seems off her food. She's been eating less than usual, and won't eat foods that she normally would eat i.e. cereal 
Could it be that she's had a bad reaction to a pesticide or fertiliser used on the fruit?! I don't know what country the fruit came from, so should I go back to the market and ask the woman on the stall?
I'm taking DD to the dr tomorrow, so I'm assuming they will ask for a stool sample. Would that be able to determine the cause of the problem?