pH control is the measurement and management of acidity or alkalinity in a food or beverage. In food production, pH affects flavour, texture, enzyme activity, fermentation and the ability of some microorganisms to grow. It is an important control in products such as pickles, fermented vegetables, sauces and certain preserved foods, but pH alone does not guarantee food safety.
The pH scale describes hydrogen ion activity in a solution. A value below 7 is acidic, 7 is neutral and above 7 is alkaline at standard reference conditions. The scale is logarithmic, so a change of one pH unit represents a tenfold change in hydrogen ion activity. Food pH can vary within a product, especially when it contains solid pieces and liquid.
pH measures hydrogen ion activity. Titratable acidity measures the amount of acid that can be neutralized in a defined test. Two foods can have similar pH values but different titratable acidity and perceived sourness.
A pH of 4.6 is an important boundary used in the classification and control of certain acidified and low-acid foods, but it is not a universal safety target for every recipe. Equilibrium pH, formulation, water activity, heat treatment, packaging and storage all matter. Commercial shelf-stable products require a validated process and, where required, review by a qualified process authority.
Chef’s tip: use a calibrated pH meter, sample the product correctly and record the result. Never rely on a taste test or an unverified recipe to establish the safety of a preserved food.
This term is one of hundreds covered in depth across OCS courses, learning paths, and 1-on-1 coaching with Chef Eric.
