well i dont think its any of those because ive noticed it for years so i just quit eating butter for the most part and i just have been eating it again on occaison but i remeber like just the fumes of melted butter makes me smell too if i melt over a stick of butter to make rice crispies or fresh caremel
Hello and hope you are doing well.
Smelly burping can be due to viral infections or due to food intolerance like lactose. It could also be due to food staying for longer time in the stomach like gastroparesis or due to an infection with giardiasis. So, if your symptoms persist, consult your doctor to rule out an infection.
Hope this helped and do keep us posted.