my saliva stink no matter I eat or not eat anything that day

why?
I've checked my pH level of saliva recently. Its nearly to 7 or sometimes alkaline. Although I feel acidic in my mouth, the test shown my saliva is alkaline more than acidic. But how come no matter I eat or even dun eat anything, my saliva is still stink. The smell is really like shit. I'm wondering is it the main cause of my bb Tweet