Meat allergy is rare in adults and not readily recognized

Meat allergy is rare in adults because it is normally outgrown during the first years of life.

Beef among mammals and chicken among birds are most frequently involved. The major allergens are serum albumins and immunoglobulins (from blood).

Meat allergenicity can be reduced by various treatments - heat, homogenization and freeze-drying.

Cross-reactivity has been described between different meats, between meat and milk or eggs and between meat and animal dander.

Most patients allergic to red meat are sensitized to gelatin. Alpha-Gal IgE might be the target of reactivity to gelatin (JACI, 2012).

References:

Meat allergy. Restani, Patrizia; Ballabio, Cinzia; Tripodi, Salvatore; Fiocchi, Alessandro. Current Opinion in Allergy and Clinical Immunology. June 2009 - Volume 9 - Issue 3 - p 265-269.
A Strange Itch, Trouble Breathing, Then Anaphylactic Shock http://nyti.ms/2D79in4 - mammalian meat allergy (M.M.A.) can be confirmed with a blood test that identifies antibodies to alpha-gal
Cross Reactions Among Foods (PDF).
A small number of people who are allergic to cat may also get allergic reactions when eating pork http://goo.gl/zVSaN
Image source: Varieties of meat, Wikipedia, public domain.