Yesterday 50,000 people marched through Porto Alegre Brazil to mark the opening of the 5th annual World Social Forum (WSF). The southern Brazilian city has been the site of three of the four previous forums, drawing 120,000 participants from around the world. The five day event consists of conferences, workshops and panel discussions about a vast spectrum of issues, focusing specifically on building alternatives to neo-liberal economic policies.

The annual forum coincides with the release of a new report from ActionAid about the effects of corporate consolidation of the worlds food sources. The report states that 30 companies now account for a third of the world's processed food; five companies control 75% of the international grain trade; and six companies manage 75% of the global pesticide market. It finds that two companies dominate sales of half the world's bananas, three trade 85% of the world's tea, and one, Wal-mart, now controls 40% of Mexico's retail food sector. It also found that Monsanto controls 91% of the global genetically modified seed market. Monsanto was in the news earlier this week as it was announced that they were acquiring Seminis, the world's biggest produce-seed company.