why does my belly button smell like cheese???

Hi my mum used to sing a song to me when i was little it went like this. melly melly has a smelly belly button. My belly buttun in all truth smell like toxic watse with a hint of cheese it,s quite wet in their too like the bottom of a brie container 3 days after opening left in bright sunlight. Is this bacteria? because anything i use to try and rid my button of this humm fails. i wash it everyday but it still could turn elephant sealsto the use of perfume. do you have any suggestions.