Here is the sentence again:
After listening for weeks to her boyfriend Steve bragging about his mother's
chili, Amy anticipated the first delicious spoonful,
the hair floating among the beef and beans, however, killed her appetite.
Amy anticipated the first delicious spoonful is the first main clause. The hair floating among the beef and beans killed her appetite is the second main clause. To connect these two clauses with a comma is to create a comma splice, a major error.
To fix the problem, you could put the word but before the; a comma with a coordinating conjunction can legally connect two main clauses. Then delete however since it means the same thing as but.