Hamburger such as , due to the occasional initial improper preparation of the meat, so caution is needed during handling and cooking. Because of the potential for food-borne illness, the USDA recommends hamburgers be cooked to an internal temperature of . If cooked to this temperature, they are considered well-done. Burgers can also be made with patties made from ingredients other than beef. For example, a "turkey burger" uses ground turkey meat, a "chicken burger" uses ground chicken meat. A "buffalo burger" uses ground meat from a bison, and an "ostrich burger" is made from ground seasoned ostrich meat. A deer
Rudolf Hamburger copies were sold. The East German authorities invited Rudolf Hamburger to exploit his new-found fame (if only as a bit-part player in his wife's success) by producing a volume of his own, but what was envisaged was a piece of propaganda controlled by the government, and Hamburger rejected the offer with an uncharacteristic absence of courtesy. He was nevertheless furious that Ursula's book concentrated on Ursula's espionage success. He felt that it unjustifiably played down his own contribution to their espionage partnership between 1930 and 1940. It may very well be that after this he redoubled his own work on