Regarding blasto, it depends who you talk to, there is conflicting information. Read Ken Boorom's newsletter. There are many sub-types of blasto, meaning that some are pathogenic while others are not.
My guess is the mucoid builds up over time, I would guess that is comes from immune/inflammation activation. The gut has most of your immune system (70%), for good reason since it is the most susceptible to infection.
A note for all of us, practice
safe hygeine, wash all fruits and vegetables and cook to safe temperatures.