498. If the Food Should Happen to Be Destroyed
Brachos 4:10
One should not recite a bracha over any food or beverage until it has been brought to him. If he recited a bracha and only after that was the food brought to him, he must recite a second bracha. If a person had food in his hand and recited a bracha, but he dropped the food and it was burned up or washed away by a river before he could eat it, he should take more food and recite the bracha again, even if it’s the same type as the first food. He should also say, “Blessed be the Name of the One Whose glorious kingdom is forever and ever” so that the first bracha will not be considered as having been recited in vain. One may stand over a stream of water, recite a bracha and drink. Even though the water he drinks is not the same water that was before him when he recited the bracha, such was his original intention.
Brachos 4:11
Food that is eaten during the meal because of the meal does not require additional brachos before or after. The bracha of HaMotzi recited at the beginning of the meal and the bentching recited at the end cover everything, because everything is subordinate to the meal. Food that is eaten within the meal but not because of the meal requires a bracha before eating but not after. Food eaten after the meal, whether because of the meal or not, requires brachos both before and after.