i        Food_group
0          Flake
1          Flake
2          Flake
3         Almond
4          Drink
5          Drink
6          Flake

data["food_group"] = data.food_group.apply(lambda x: "other" if x.value_counts()==1 else x)

AttributeError: 'str' object has no attribute 'value_counts'