Some of the food that my family buys contains haram ingredients. Is it wrong for me to help moving the groceries without being sure that the food is halal?

All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.

What is considered here is what is apparent to you; if you know that the food includes something that is haraam (unlawful), then it is not permissible for you to help them in carrying them, because it is helping in sin, as Allah says (what means): {And cooperate in righteousness and piety, but do not cooperate in sin and aggression. And fear Allah; indeed, Allah is severe in penalty.} [Quran 5:2]

It should be noted here that you should advise them in a soft and gentle manner to stop buying or eating what is forbidden, as offering sincere advice is pivotal to the religion.

However, if it does not appear that the food contains what is forbidden, then there is nothing wrong with carrying it, and it is not necessary to investigate whether or not it contains something that is forbidden. In principle, one should think good of a Muslim and regard him as innocent of sin until it is proven otherwise.

Allah says (what means): {O you who have believed, avoid much [negative] assumption. Indeed, some assumption is sin.} [Quran 49:12]

Allah knows best.