Characterization of the heat treatment undergone by milk using two inhibition ELISAs for quantification of native and heat denatured α-lactalbumin

Dairy industries are interested to know the heat treatment undergone by milk for controlling the quality of drinking milks or to control their heating systems. The purpose of this work was to develop a specific and sensitive technique for classification of the heat treatment a milk has been submitted to, without disposing of the original raw milk. For this purpose, alpha-lactalbumin was chosen as a bioindicator of heat treatment, and monoclonal antibodies specific for its native or heat-denatured form were raised and used in two inhibition ELISAs. ELISA allowed differentiation among raw, pasteurized, ultrahigh-temperature-treated, and sterilized milks without even having to know the alpha-lactalbumin concentration of the original raw milk. However, this technique was more suitable for intense heat treatments such as UHT treatment and sterilization because of the heat stability of alpha-lactalbumin.