hey nicole~ WELCOME!
as far as sealing with corks, many products use corks as seals. Wine, oils, hot sauces, booze,
perhaps look at it as a processor would look at it, be it wine, booze or olive oil.
The bottle and all components need to be as sanitary as possible. Boil the "hot sauce recipe" before transferring to the sanitized glass bottles, cap, invert......
Is there a reason you are asking about the corks other than it looks cool and is a good marketing gizmo?
I would venture a guess that those products that do use a cork are very sophisticated in their cleanliness and sanitation regimines.
Talk to your "process authority" person, be it your local health department or your state dept of AG person....whoever is in charge of licensing food processors in your area. They are the ones who will work with you to determine if it is (safe?) LEGAL and most importantly, if it will have any bad effects.
If you are looking to market something, work with your food processing authorities. If you just want to put some stuff in a jar and give it away to friends and family,.....Perhaps follow guidelines for wine bottling for sanitation of corks and bottles, and then boil whatever you are mixing before bottling, invert, etc.
Nova's right in that people store wine horizontally to keep the cork moist and PLUMP and preventing oxygen from getting into the bottle.