There is an existing question here Mangos on flight from Palawan to Manila? that addresses a different case.
We are hopping over to Russia tomorrow, I will return the same day/next day but my family will stay on for several weeks. Our family members there have asked us to bring some fresh mangos (we can get them at the Tesco here in Essex). No clue as to whether or not the authorities will get upset about this. We are all Russian nationals so there's standard immigration formalities, but do mangos need to be declared or certified? Is it ok?
At request, we are also bringing two large jars of American peanut butter (one smooth, one crunchy). They are unopened and well within the 'use by' dates. Is it ok?