https://www.pickyourown.org/ph_of_fruits_and_vegetables_list.htm

pH stands for the "percent hydronium" in a solution which is the amount of hydronium in a solution. Acids have more hydronium than bases, which have more hydroxide ions.

pH is useful in many ways in the food industry such as, to produce foods with good qualities, avoid health problems of people ingesting the food, and to keep the product fresh. In order for food to have these qualites, chefs and producers of these materials need to know the appropriate pH of each food, so when the pH goes out of that range, they can discard of it and get a new one. Just a small change in pH can cause the food to spoil. pH can cause changes in flavor, consistancy, and expiration dates.

pH measures the acidity of basicity of a solution, or how much acid (hydronium) or base(hydroxide) is in a solution. A soultion with a pH of 0-6 is an acid. A solution with a pH of 8-14 is a base. A solution with a pH of 7 is neutral, and is most likely water.

https://www.fiorinichiropractic.com/Patient-Education/Top-News-Articles/Top-News-Blog/ArticleID/107/Balanced-Body-Chemistry-Understanding-pH

pH is a very important factor in body chemistry. The body's chemistry maintains a specific pH to stay healthy. The body maintains a pH of 7.4 in the blood. Except for urine and saliva, the body is slightly alkaline or basic. If the body gets too acidic, it could develop cancer, cardivascular damage, and joint pain. If the body gets a high alkalinity, it could develope liver problems, allergies and chronic infections.