For the last month or so I have been writing a chapter on the advantages and disadvantages of drinking raw milk for a new dairy science/ technology book. Because of my interest in modelling I have been modelling the denaturation or loss of biological activity of the major humoral and non-specific antimicrobial proteins. I have provided access to a free OnLine calculator that will enable those interested to do their own calculations. IgA is the most sensitive of the Igs in milk to heat and the calculations indicate minimal loss of activity after 72 °C for 15 seconds (statutory HTST pasteurisation of milk). To use the calculator the Decimal reduction time of the biological factor or quality factor is required e.g. 319 seconds for IgA at 72 °C. See https://www.dairyscience.info/newcalculators/ig.asp . More in the future.
Statutory HTST pasteurisation has minimal effects on the major antimicrobial proteins in bovine milk