Actually PH changes according to the different parts of your body like this:
Mouth/Saliva= 5.7 to 7.0
Esophagus = 7.0
Stomach= 1.5 to 3.0 Acid...
Small Intestine Duodenum = 4 to 5
Colon should be acid : 5.6 to 6.9 to allow acidophilus to thrive
Small intestine Jejunem and Ileuum = 6.5 to 7.5
Blood=7.4 Alkaline
Lactobacteria= 4.5 to 6.4