Yellow lab - harmful foods

Question
My son and daughter- in- law diligently provide a high quality diet for their adult yellow lab feeding twice daily and of course plentiful water.  My question concerns food items "swiped" by the lab such as an avocado off the counter or even a packaged cream cheese Danish  during my visit...I feel concerned because this behavior occurs mostly when I visit and causes us worry regarding digestive upset or allergies and especially why ishe does this more during my visits.  I adhere to their practices and placement of items etc though I may not be as diligent in watching her every move simply because I am not accustomed to doing so.  I certainly do not want to cause my grandpuppy any harm nor worry for my children .  Thank you for reading and responding to my concern...she just ate the avocado seed and all...she did chew it, rather than swallowing whole, thankfully.

Answer
Avocado seeds appear on the lists of harmful things, but I doubt if a single one will cause a problem.  Other than that, I am not sure what to say.  Labs can be difficult, requiring a close eye all the time.  We had several raids on our trash over the weekend.  My son in law said he though his Shepherd could open the closet door where we keep it.