Table of pH values for common foods
FDA Bad Bug Book
Technical manual on pH theory and the use of pH electrodes to measure product acidity.
GLI International and Hach Company
Dressings, sauces, marinades, and similar food products depend on their acidity to prevent spoilage. Because foods without adequate acidity may allow the growth of microorganisms that cause foodborne illness, the federal government regulates the manufacture of these products.
North Carolina State University Department of Food Science
From Breidt, F and others. 2010. Use of Linear Models for Thermal Processing of Acidified Foods. Journal of Food Protection Trends. 30(5): 268-272.
How to Measure the pH of Liquid and Solid Foods, How to Calibrate a pH Meter, and How to Measure Water Activity in Foods. From the Northeast Center for Food Entrepreneurship, Cornell University.