aw (water activity): a measure of the free moisture in a product and is the quotient of the water vapor pressure of the substance divided by the vapor pressure of pure water at the same temperature. In simpler terms, it is a measure of relative humidity.
Where acid is added to large particles (e.g., whole peppers), equilibrium might not be reached for several hours or several days. If this is the case, the product may need to be refrigerated until a pH of 4.6 is reached. The anticipated equilibrium pH can be determined immediately after processing by blending the entire contents of the finished product container and taking the pH or blending the solid particles and acid brine in the proportion present in the finished product and taking the pH.
flow diagram: a diagram of the sequence of operations in a processing plan. example.
natural pH: the pH prior to processing. However, if a processor receives an acid food (including fermented foods with a pH of 4.6 or below) and during processing allows the pH to rise above 4.6 (through washing, lye peeling, etc.) and then adds an acid or acid food to reduce the pH to 4.6 or below, that product would be considered an acidified food.
pH: a measure of the acidity or alkalinity of a solution, numerically equal to 7 for neutral solutions, increasing with increasing alkalinity and decreasing with increasing acidity. The pH scale commonly in use ranges from 0 to 14.
scheduled process: the process selected by a processor as adequate for use under the conditions of manufacture for a food in achieving and maintaining a food that will not permit the growth of microorganisms having public health significance. It includes control of pH and other critical factors equivalent to the process established by a competent processing authority. The process, which is filed on Form FDA 2541a, is considered to be the scheduled process. Only those critical factors, as established by a qualified person, which are necessary to achieve and maintain a safe product, including maximum equilibrium pH, are required to be filed with FDA. All critical factors listed on the process filing form shall be controlled and records of the results of tests or determinations shall be kept.
water activity (aw): is a measure of the free moisture in a product and is the quotient of the water vapor pressure of the substance divided by the vapor pressure of pure water at the same temperature. In simpler terms, it is a measure of relative humidity.
Wednesday, March 12, 2014