The biofuels boom has contributed to the recent spike in food prices that threatens the world's poor. In Brazil, home of ethanol made from sugar cane, it's had another unintended consequence: slavery. The use of forced labor to work in sugar cane plantations is "a growing trend," according to the U.S. State Department's latest report on human trafficking.

The annual report, released last week, documents sexual exploitation and forced labor in 170 countries. It is always a tough read. This year's edition records the appalling abuse of men, women and children in brothels, factories and farms – often while government looks the other way – and spots trends. Every country receives a ranking based on its record in prosecuting exploiters, protecting victims and preventing abuses.

Oil-rich Russia, for instance, is now more likely to import prostitutes and forced laborers, often from Central Asia, than to export them. India, which has taken welcome steps to protect prostitutes and child laborers, has done little to help bonded workers, usually of lower castes. China is cited for, among other things, a recent scandal involving the relocation of children from the interior to work in electronics factories in coastal Guangdong province. It's also criticized for its treatment of tens of thousands of North Korean refugees, who are sold as brides or into brothels or forced to work under brutal conditions in logging camps.

The report also lists products made with forced labor. They include shrimp from Thailand and Bangladesh; clothing from Bangladesh, India, Jordan and Malaysia; cotton harvested in Uzbekistan; cocoa from Ghana and Cote d'Ivoire; and pig iron from Brazil. Not all products in these industries are made with slave labor, and it's too bad the report does not identify companies that buy or sell tainted products.

There is some good news. Among the countries that improved are Mexico, Croatia and Kenya. Madagascar is the only nation in Africa to receive top marks, thanks to a government determined to wipe out sexual tourism. The United Arab Emirates is the only Middle Eastern country other than Israel to reach the second tier, due to its efforts to combat abuse against foreign workers employed as domestics or in construction.

U.S. Ambassador Mark Lagon says "there is now more awareness" of human trafficking than there was seven years ago when his office began its work, and more countries have enacted laws to combat it. That said, modern-day slavery remains a scourge. The more light that can be shed on it the better chance of wiping it out.