It would be difficult for any president to lower food prices due to the negative stigma of deflation. It would be even harder to do so this quickly. Just saying that to be fair.
Will his policies eventually lower food prices? It's unlikely. We do get some food from Canada and Mexico. The tariffs will impact that. More specifically, we get a lot of pot ash from Canada, which is a key fertilizer. That means tariffs are likely to also impact the costs of our home grown food supply.