Israel'sOsem Group, Tel Aviv, said it purchasedTribe Mediterranean Foods LLC, a Taunton, Mass., processor and marketer of refrigerated all-natural and organic hummus products. Media reports  the purchase price at $57 million. A diversified food processor, Osem has operations in the United States, United Kingdom, Sweden and the Czech Republic. Officials said Tribe Mediterranean will be incorporated into Osem's Prepared Foods Division. Nestle S.A., Vevey, Switzerland, owns a majority stake in Osem.