ConAgra Foods Inc. has agreed to acquire Ralcorp Holdings Inc. for about $5 billion, creating one of the largest packaged food companies in North America and concluding a pursuit that began in March of last year, Bloomberg reported. The offer of $90 a share by Omaha-based ConAgra is 28 percent more than Ralcorp's closing price Monday, the companies said today in a statement. Including debt, the transaction is valued at $6.8 billion and is expected to be completed in March. ConAgra's purchase of St. Louis-based Ralcorp will create a company with sales of about $18 billion and more than 36,000 employees.