You pose some good questions. While earnings could come in higher than expected, their tract record over the past several quarters has been right on, or a .01 either way. And no the demand for food hasn't dwindled, but their costs for ingredients could be going up due to El Nino.
My concern for HNZ is more a valuation one. With it's current PE at 28, which is higher than its ever been in the past 5 years, and a PEG of 2.8 the company has more downside potential than upside.
It's PE range in the past few years has been 16-30, and its virtually impossible to trade at a PE above 28 for ever. At some point it's going test more normal PE levels, say 20-22, and where better to start from than such extreme highs.