The United Kingdom has already arranged continuity and mutual recognition agreements with a wide variety of countries and economic blocs which it is trading with via the European Union. In most cases trading arrangements with non-EU countries will simply be rolled over and it will be possible for the government to pursue its own FTA's with large trading partners which are currently subject to EU duties (such as the US and Canada). So as I said, in the case of a clean break exit there would probably be some disruption and limited availability in the near term, but there is no reason to suspect that this would cause malnutrition or destructive price rises. And of course any concerns about EU tariffs would be immediately rectified if an independent FTA with the European Union could be reached (which would be exceptionally easy were it not for the ridiculous brinkmanship currently on show).