So looks like food of the non chlorinated chicken kind may get cheaper post Brexit (it was very generous of all those Brexit voting farmers to vote against their economic interests). From the FT which requires registering and maybe a bit technical:
https://www.ft.com/content/92bb5636-a95b-11e7-ab55-27219df83c97
To summarise a number of WTO countries are objecting to the proposed splitting between the UK & EU of low tariff quotas on imports of their countries agricultural products as they may limit their ability to export at low tariff levels to the two.
Anyway if this happens the UK may have to accept lower tariffs than it wanted to on some agricultural imports. So good news on Brexit! (assuming you're ignore the wider context of countries (especially the US) not being willing to bend over backwards to give the UK everything it wants under WTO rules or you're a farmer).