I still don't see a reason why tasting them should be allowed.
Even though it's likely that the manager would let you taste it if you seriously want to buy grapes you still have to ask before.
To tell you the truth I never really thought about it, I did it because that's what I saw when growing up and went shopping for grapes.
When it comes to grapes where it's a cluster of fifty to a hundred grapes I taste one to know if I should buy the whole cluster or if I should take only half the cluster, by tasting one of the grapes. Now in regards to an apple an orange a lemon and onion each apple each lemon is its own thing, so in that scenario there's not what to taste.
and believe it or not when it came to cherries just like the grapes when it's an open bag and it's made for people to touch and taste I did the same thing before buying a bag of
(Cherries).
Now in regards to strawberries blueberries and all the berries which came in a container and it was closed I wouldn't open it, it's only where the bags were open and where they would assume customers would go ahead and taste the product before buying that's where I went ahead and tasted, as that's the reason why they leave it open for people to go ahead and taste.