All-American beef and pork are staples of the U.S. diet, particularly in the southern states with proud barbeque traditions. Unfortunately, researchers from Vanderbilt University have some bad news: An encounter with a tiny little pest, the lone star tick, may trigger an allergic reaction to the beloved beef. Scientists are as of yet unsure of why this is or how long it lasts.

“It is not completely understood exactly how the allergy starts,” said Robert Valet, M.D., assistant professor of Medicine. “The thought is that the tick has the alpha-gal sugar in its gut and introduces it as part of the allergic bite and that causes the production of the allergy antibody that then cross-reacts to the meat,” he said.

The symptoms are more or less what you’d expect from a food allergy – rives, rashes, swelling, and even more severe symptoms like vomiting and diarrhea. Alpha-gal patients can safely eat poultry, but feel the effects when consuming red meat, which in this case includes both beef and pork. That’s bad news for southerners looking to get their fill of pulled pork or brisket.

“I think it is something that certainly belongs among the most important food allergies, particularly in the Southeast,” Valet said. “Certainly these patients can present with every bit as severe of an allergy as someone who is allergic to peanuts.”

Valet said he diagnoses patients with a blood test but there is not a good way to desensitize people once they become allergic to this food, so they have to avoid red meats and, in some cases, milk as well.