Abstract: A method for treating an aqueous protein solution so as to kill microorganisms which may be present therein, but without causing coagulation, comprises either (1) mixing the solution with sufficient enzymatically produced protein hydrolysate (H1) to prevent coagulation of the mixture when the mixture is subsequently subjected to a heat treatment to kill microorganisms, and then subjecting the mixture to such a heat treatment, or (2) using one or more enzymes to hydrolyze protein in the aqueous protein solution to an extent sufficient to prevent coagulation of the resulting liquid hydrolysate (H2) when it is subsequently subjected to a heat treatment to kill microorganisms, and then subjecting the liquid hydrolysate (H2) to such a heat treatment. The use of aqueous protein solutions treated in this manner in the production of a foodstuff, such as a meat-based foodstuff, contributes very significantly to reducing any risk of contamination of the foodstuff by harmful microorganisms.