Traceability indicators for heat treatments of milk

Abstract

Because of its high nutritional value, milk is an excellent medium for microbiological growth. Consequently, fresh mil necessitates a heat treatment in order to guarantee a safe and shelf-stable product. To overcome processing of the product as well as to control if heating was adequate from a safety point of view, criteria need to be defined. In order to define such criteria, the impact of a thermal process on milk has to be known.
The changes in solubility of β-LG solutions as an indicator for milk pasteurization and the color development measured by changes in absorbance at 420 nm in milk-resembling model systems at pH 7.5 as indicator for sterilization process were used in this study to quantitatively describe the heat induced changes in model systems. The extent of changes measured by the decrease in solubility and increase in absorbance could be described by a first-order fractional conversion model, which allowed calculation of activation energy.