Some Muslims claim that not all Halal food sold as Halal is actually Halal and not all food sold as vegetarian is actually vegetarian. Is this true? Also what happens if we do consume something Haram unknowingly, which is being passed off as Halal, is there any sin on us?

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.

In principle, slaughtered animals of the People of the Book are lawful unless we have proof that such animals died by electric shock, etc., or have been dedicated to something besides Allah. Then it is unlawful to eat such meat.

Allah Says (what means): {Prohibited to you are dead animals, blood, the flesh of swine, and that which has been dedicated to other than Allah, and [those animals] killed by strangling or by a violent blow or by a head-long fall or by the goring of horns, and those from which a wild animal has eaten, except what you [are able to] slaughter [before its death], and those which are sacrificed on stone altars, and [prohibited is] that you seek decision through divining arrows.} [Quran 5: 3]

As for vegetables, it is completely lawful to eat them unless they are contaminated with harmful materials that make them unlawful for the Prophetic Hadeeth: “There should be neither harm nor reciprocal harming.”

However, if you eat something that you think it is slaughtered according to Islamic rites, and later you learn that it is not so, then there is no blame on you, Allah willing.

For more benefit on slaughtered animals, please refer to Fatwa 82323.

Allah knows best.