Iron Gut

For the duration, one willing creature you touch has resistance to poison damage and advantage on saving throws against poison. When the affected creature makes a Constitution saving throw against an effect that deals poison damage or that would cause the creature to become poisoned, the creature can choose to succeed on the saving throw. If it does so, the spell ends on the creature.
While affected by this spell, a creature can't gain any benefit from consuming magical foodstuffs, such as those produced by the goodberry and heroes' feast spells, and it doesn't suffer ill effects from consuming potentially harmful, nonmagical foodstuffs, such as spoiled food or non-potable water. The creature is affected normally by other consumable magic items, such as potions. The creature can identify poisoned food by a sour taste, with deadlier poisons tasting more sour.