The circle R is the mark of "registered trademark", which means that the trademark has been applied for registration with the National Trademark Office and has been reviewed and approved by the Trademark Office to become a registered trademark. TM is a sign that an application has been submitted but a trademark certificate has not been obtained.

The R in the circle is the first letter of English register. Therefore, if you buy milk powder, you should buy products with registered trademarks, which are relatively safe.