Individuals Allergic to Cow's Milk Should be Vigilant When Consuming Beef Because It May be Injected Beef.

Background: Natural “marbled” beef is popular in Japan, but is expensive. “An injected beef”, which is processed to improve texture of dairy cow’s meat to give palate feeling of marbled beef by injection of fat, is sometimes served at relatively low price in restaurants. Such meat might contain milk protein (casein) as one of food additives.

Methods: A 2-year-old boy with a history of adverse reactions to hens’ eggs, cow’s milk, and wheat from the age of 6 months had an anaphylactic reaction after eating beef steak at a hotel restaurant. This reaction occurred even though his parents asked the restaurant to ensure that the dish was free of hen’s eggs, cow’s milk, and wheat. We tried to discover the cause of this anaphylactic reaction. We asked the hotel restaurant by telephone about the ingredients of the dish they had served and to send some pieces of beef. We undertook a skin prick test with the meat that they sent. We determined the quantity of cow’s milk protein in a piece of injected beef using an enzyme-linked immunosorbent assay (FASTKIT™; Nipponham, Tokyo, Japan).

Results: The hotel restaurant did not use hens’ eggs, cow’s milk, or wheat, but they used injected beef that was labeled as containing casein, and they were not aware of this fact. The skin prick test was strongly positive for raw injected beef and heated beef. A piece of injected beef contained 1.193 mg/mL of cow’s milk protein, which was sufficient to induce an allergic reaction.

Conclusions: Even if injected beef is labeled appropriately, an allergic reaction can occur if chefs do not know that casein is a milk protein. Chefs need to be informed (in detail) about food allergies.