What Causes Foul Smell While Taking Out The Tampon?

i am on my period - i use tampons - i have used tampons for 14 years - never befor hae i had this happen - i took out my tampon and i am not bleeding much and the tampon smells FOUL - but not my vagina just the tampon with the blood - i have not had a regular period for the last 2 months i have only spotted once in one single day 5 times over the last 2 months - i just had a baby in july 09 -