Actually, it is much harder for a domestic company (specially if it is not very large) to get away with this kind of behavior.
Brazil has very strict work laws, up to the point that even nannies and house cleaners are jobs under strict regulation. This case with Samsung is indeed very worrying, however it is not as common in companies as most people would expect in Brazil. We have hundreds of unions who have very resonant voices in politics.
Work conditions abuses in Brazil come mostly in two flavors:
i) Rural work in farms, specially up North. It is not uncommon to have people working under slavery regime in some farms, and some of the scandals involve even politicians who are also big farmers. The workers are usually very poor people who are deluded into getting a job in a farm and getting rich. Their travel costs are covered by the farmer, and so is living cost and food, and they stay in an eternal debt without ever leaving. They end up working 18 hours shifts for food, with no sanitary conditions, etc. This is taken seriously in Brazil, but more often than not the responsible for this are rich people, so they get away with fines and never see the inside of a jail cell.
ii) Manual labor done by foreigners, in particular by South Americans. In Sao Paulo city there are 200,000 Bolivians, 80% of them are illegal, and most of them work with sewing. They work under very poor conditions and earn very little. Since most of them are illegal, and most of them are in debt with people who helped them to get here, they are afraid to seek the police.
But in companies this is not the case. Even to me this news about Samsung came as a shock.