What are the effects of consuming haram food ignorantly?

lately there is a serious issue of haram meat being labeled as halal and it has been consumed by muslims unknowingly. I read somewhere that any food that is haram or its source is from haram source will render it to become part of the flesh of the person who ate and will weaken his iman. Is this correct? Pls advice preferably with hadiths to deny or support. Jazakillah