Still have the research on undecenoic acid being anti-bacterial against “good” bacteria?
Not all acids have antibacterial activity against “good” bacteria. Good bacteria secrete good acids such as acetic acid, lactic acid, propionic acid, butyric acid etc… Even some good flora secrete capric acid. I think certain acids work against certain strains.
Probably depends on the strength of the acid as well. The acids that “acid”ophilus secrete might be weaker acids.