I was very much hoping he would buy General Mills (GIS).... but that is probably not going to happen with the holding of Heinz (a good deal). Con Agra may be the next biggest food company, with solid cash flow, good brands, and a business he understands. The firm could probably be bought for about 17.2 billion dollars (or a per share price of just over 42). There is some overlap with Heinz, but that can still be profitable as they would be operated separately (similar to how firms like Proctor and Gamble own competing brands... or PepsiCo owning competing brands of potato chips).
So, I think it would be a good move... I do not expect it to happen. I think that the holding company that BRK will own 50% of common equity right now, will expand using smaller firms. I think that B&G Foods and Pinnacle food would be two great choices (each at about 1-2 billion) because their business model is SO Buffett like. BRK also has a right to buy 5% more of Heinz common equity as part of the preferred deal. As 3G partners want to cash out their stake, BRK will likely buy it up. The holding company will likely eventually be almost entirely owned by BRK... Not that the holding company being limited to smaller acquisitions would preclude BRK from buying CAG (which they could do with cash right now without difficulty).