pH value
The pH value describes the hydrogen ion concentration, i.e. how acidic or alkaline a liquid is. Pure water has a pH value of 7. It is not so much a question of how much acid is present, but more of its concentration. Acidic solutions are < 7, alkaline solutions are > 7; the more acidic the chilled goods, the lower the pH value, the more alkaline, the higher the pH value. If the pH value is lower than 4, only yeast and mold are capable of any activity; between 4 and 6, it is carbohydrate-degrading bacteria in particular which may be found to be active; at a pH value of between 6 and 8, protein-decomposing bacteria (rot bacteria) and mold develop, in particular.
Some examples of pH values:
  • Lemons 2.0
  • Tomatoes 4.3
  • Cows' milk between 6.5 and 7

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