Mike, only just been able to get onto the site. For some reason it didn't connect after my last post. No, I haven't tried a Hershey bar but decided to see what other people thought and this is what came up (not being ironic):
According to MailOnline, the chemical found in Hershey's chocolate, vomit, parmesan cheese and sour butter is called butyric acid. ... They also claim the butyric acid — which gives vomit its acidic smell and taste — gives American chocolate its "tangy" flavor.
Needless to say Mike, I won't be trying one in a hurry!