What is pH in Food?

pH in food refers to its acidity or alkalinity, measured on a scale of 0 to 14. A pH of 7 is neutral; below 7 is acidic, and above 7 is alkaline. The pH of a food directly relates to the concentration of free hydrogen ions (H+). Acids release these ions, contributing to a food's sour taste. The pH value is crucial in food safety and processing, significantly impacting the required heat treatment for preservation.

• Acidity: Foods with a low pH (e.g., lemon juice, with a pH around 2) are highly acidic. These often have a sour taste.
• Alkalinity: Foods with a high pH (e.g., baking soda) are alkaline or have low acidity.
• Neutral: A pH of 7 indicates neutrality (e.g., pure water).

The pH of a food isn't static; it varies based on factors such as the type of food, growing conditions, and processing methods. For example, the pH of apples can vary depending on the variety and how they're prepared. Baked apples with sugar will have a different pH compared to a fresh, raw apple.

Importance of pH in Food

• Food Safety: pH is critical for food safety, particularly in canning. Low pH (generally below 4.6) inhibits the growth of harmful bacteria, thus reducing the need for extensive heat processing. Commercial canning often targets a pH of 4.2 or below for safety.
• Food Processing: pH influences various processing techniques, including fermentation, and impacts texture, flavor, and color.
• Health: While the concept of an "alkaline diet" is popular, its effectiveness in directly altering blood pH is scientifically debated. The body has sophisticated mechanisms to regulate blood pH, preventing significant shifts. However, the renal acid load from food choices might influence urine pH.

Examples of Food pH Values

A range of foods and their approximate pH values (note that these values can vary):

• Highly Acidic (pH < 4): Lemon juice (2.0-2.6), Vinegar (2.4-3.4)
• Acidic (pH 4-6): Tomatoes (4.0-4.5), Apples (3.0-4.0)
• Neutral (pH 7): Pure water
• Alkaline (pH > 7): Baking soda (8.0-9.0)

Note: The pH values provided are approximate and can differ based on several factors. The Clemson University Extension provides a detailed list of pH values for numerous common foods and ingredients https://www.clemson.edu/extension/food/food2market/documents/ph_of_common_foods.pdf.