Blood, red blood derivatives or blood-containing materials such as liver are decolorized for use in food or animal food products by oxidants such as hydrogen peroxide or calcium or sodium peroxide. Excess peroxide can be removed and a desirable color achieved by adding further blood, blood derivative or meaty material. Reaction with the peroxide can be facilitated by a pH reversal process in which the pH is raised or lowered by at least 2 units and then restored. Heat or a combination of heat and pH reversal can also be employed. Flavors and other additions added to the blood or other material before decolorization are locked in the resulting product. The decolorized material can be canned as a mince-like product or mixed with other foodstuffs.