Often meat allergies are overlooked because allergy to meat in general, is fairly uncommon. However reactions can range from anaphylactic to digestive issues. It is often thought that the person is not allergic to meat it self, but an additive in the meat.
Pork, beef, chicken any meat can cause allergic reactions more commonly associated with the big eight allergens and the reactions they cause. Anaphylaxis, rashes, hives, digestive issues ranging in severity.
If you are extremely allergic to a certain meats, even cross contamination can become a problem. Even certified vegan products can be made on the same line as meat and milk products. This usually is not a problem for someone with a minor allergy.
People who avoid meat, for religious reasons, often have certification measures that are more restrictive, no pork product would enter any Muslim butcher shop!
For Jews not eating pork is an observed kosher practice, though many Jews no longer follow dietary restrictions they once did. Muslims consider eating products derived from pork violation. With in Muslim certification Halaal means “lawful” or "permissible". The foods that meet Jewish dietary laws have kosher labeling. Both are “pork free” with almost no cross contamination issues with pork.
Most halaal gelatin is made from beef and never pork so it can not be considered vegetarian. Hidden Pork is usually in the form of gelatin, in such foods like marshmallows, candies, ice cream, jello, even some vaccines. There are vegan and Halaal variations of marshmallows, jello and other foods. They can usually be found is specialty stores. Vegan marshmallows or gelatin free marshmallows are a challenge.
Look for gelatin free products, research Vegan and Vegetarian sites. Remember that most vegans usually unknowingly eat foods made on the same equipment as meat. There are however exclusively vegan product lines, however even here smaller companies may share equipment with another food manufacturer.
Beef allergy in children with cow's milk allergy; cow's milk allergy in children with beef allergy. PUB MED Article
Marshmallow Fluff is gelatin free mashmellow product
Article and discussion on meat allergies
I would like to invite people to share their story with allergies or food elimination. It can be anonymously or with a link to your web site or blog.