"Bread and garlic"
Translation:Mkate na vitunguu saumu
Correct, kitunguu is the singular noun meaning an onion, while vitunguu is plural (KI-/VI- class noun). Note that "garlic" is one of those ambiguous English words which can be understood as either singular or plural. So "kitunguu saumu" really means one "clove" of garlic, while "vitunguu saumu" would be multiple cloves.