勝手に触らないでって英語でなんて言うの？

It is common in workplaces to have a staff room where there is a fridge inside.
All employees may leave their food/drink there and often food/drink gets mixed up and eaten by the wrong person!

It is quite common to put a polite notice on the food/drink item to say:
'Please don't touch' This means do not touch, taste, take or bite this item!

It can also be polite to put your name on a particular item to avoid someone taking it.

I hope that helps!

Do not touch!
In the place of 'do not' you can use 'don't'.
Don't is a contraction - do and not are combined

Hands off
This is a warning.
The person may not touch the object.
'hands' - you use your hands to touch objects..

A) Please DO NOT TOUCH
- This a direct way of saying someone should not touch something

B) Look with your eyes and not your hands.
- This is an indirect way of saying please only look (with your eyes) and do not touch ( with your hands )

I hope this helps :-)

It depends rather what your past experience is with these products and why you are thinking about placing messages on the items. Delicate and breakable things in shops sometimes have a nearby message reading: "If you wish to handle this product please ask a member of staff." However, if this problem is persistent and customers continue to handle objects, a sterner message may be appropriate:
"Hands off!"

All of the above can be used to let people know, that they should not put their hands on the glass or lean against it. A dirty display, is not very attractive.

Kindly refrain from handling these products. An employee will answer all your questions.
This makes it very clear that you must not touch the product and to direct all your
questions at one of the staff members.

Please do not handle this product - ask for assistance instead.
This means that you must not physically examine the product but to ask /request help
from a member of staff.