How many free samples is too many to eat at a store?

I ate a few too many (free) samples at a store today and a security guard showed up and approached me and said “I’ve got my eye on ya”. This is the store that I do most of my grocery shopping at so I was more than a little embarrassed, especially because I was with my wife. We were doing our shopping together and were both quite hungry because we hadn’t eaten much all day. What rule should you follow regarding free samples if they don’t specifically say to limit yourself to one? I’m so embarrassed about this I don’t know if I’m going to go back to that store again.