Do i get it right that if my food turned sour and doesn't have any signs of mold presence, i can be pretty sure it won't poison me?

https://bml.bioe.uic.edu/BML/Stuff/Stuff_files/biologist%20fix%20radio.pdf http://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1005268