A friend of mine told me that she read somewhere that Lucas said it was a "bad idea" (or whatever he called it) to introduce the concept of Midichlorians. So that is why it is never said in AOTC. But then like the contradicting prick that he is, he brought up the idea of Midichlorians again in ROTS - which didn't do anything for the story.
I remember in the theater thinking, "Oh come on! Not this again! I thought we were past this. That midichlorians were a bad call on the TPM movie. God dammit...."

Lucas could just have easily used the word "Force" over the word "midichlorian" and it wouldn't have altered Palps speech.

"He was so strong that he could influence the force in such a way that he could even stop people from dieing."

Which would then make a little connection to Yoda from ROTJ when he says "Strong am I with the force...but not that strong." And make you wonder, "Hmm...was Pleagasis (or whatever the hell his name was) really that strong? Did he have this power?"

But Lucas is stupid so he kept the concept of Midichlorians even though he said he wouldn't. That lieing rat basterd.