Table 3.

Tolerant pH range for the various organisms found in the natural environment and their location in the human body

Scientific name	pH	Body location	References
Staphylococcus epidermis	5–14	Skin	Pandey et al. (2015)
Cladosporium spp.	3.5–6.7	Oral cavity	Gross and Robbins (2000)
Streptococcus pyogenes	6.5	Respiratory tract	Savic and McShan (2012)
Helicobacter pylori	2.7–7.4	Stomach	Sidebotham et al. (2003)
Lactobacillus bulgaricus	5.8–6	Intestine, oral cavity	Rault et al. (2009)
Lactococcus lactis subspp. cremoris	6.3–6.9	Intestine, oral cavity	Rault et al. (2009)
Peptoniphilus stercorisuis spp.	6–9 (7.75)	Urinary system	Johnson et al. (2014)
Porphyromonas gingivalis	6.5–7	Vagina	Takahashi and Schachtele (1990)
Bacteroide intermedius	5–7	Vagina, intestine	Takahashi and Schachtele (1990)
Pseudomonas spp.	7	Respiratory tract	Mishra et al. (2008)
Neisseria gonorrhoeae	6.75	Vagina	Brookes and Sikyta (1967)
Bifidobacterium	4.5–8.5	Oral cavity, intestine	Biavatiet al. (2000)
Streptococcus mutans	6.5–7	Oral cavity	Handelman and Kreinces (1973)
Clostridium spp.	7–11	Intestine	Li et al. (1993)
Candida albicans	2–10	Respiratory tract, urinary system	Sherrington et al. (2017)