Chlorine-washed chicken is only one of the foodstuffs the US will want to import into the UK if it secures a bilateral trade deal after the UK leaves the EU. The overuse of antibiotics, hormone-treated beef and dairy and GM crops are commonplace in US farming. British farmers will struggle to compete with these imports unless they abandon EU standards themselves. Together with our reliance on EU agricultural workers and food imports and the impact of slower supply chains, Brexit – particularly if it involves leaving the Single Market and Customs Union – will seriously undermine food security in the UK, says Erik Millstone (University of Sussex).

The UK currently imports about 47% (by value) of all its food, while 31% of our food is currently obtained from other EU Member States. We are therefore heavily dependent on imported foods, and especially on imports from other EU countries, from which we obtain some 66% of total food imports. If the UK leaves the Single Market and Customs Union there will need to be customs and border health checks, which at the very least will slow down the flow of foodstuffs into, and out of, the UK. Transaction costs will rise, domestic UK food prices will inevitably rise, especially and if sterling depreciates against the Euro.

Furthermore, if the UK and EU fail to agree a satisfactory trade deal, and we trade on WTO terms, then standard agricultural tariffs averaging some 22% are most likely to apply to trade between the UK and the EU, which will drive food prices even higher, and aggravate economic, dietary and health inequalities. The UK could set lower tariffs on imports, but doing so would undermine the economic viability of most British farms.

UK farming, food processing and commercial catering all currently rely on visiting workers from other EU member states. If ‘taking back control’ of the UK’s borders prevents, or even discourages, those people from accepting employment in the UK, then the UK’s food supply will suffer, and so too will the viability of UK farming. A very large proportion of veterinary inspectors working for the Food Standards Agency’s Meat Hygiene Service in UK abattoirs are also citizens of other EU countries. Quite a few have already left, in part because the depreciation of sterling has already meant that the value of their UK earnings has sharply declined, and many more are planning to leave. Without them the UK’s supply of home-produced meat would rapidly decline.

If the UK tried to import food from outside the EU, it would inevitably increase the greenhouse gas emissions required to provide our food supply. If, on the other hand, we tried to reduce our reliance on imports, then the emissions from domestic food production will increase. To maintain a food supply that approximates to the patterns to which UK consumers have become accustomed would require rapid intensification and an increased reliance on resources that should be conserved rather than depleted. The concept of ‘sustainable intensification’ has been articulated, but it is not close to being delivered. With the rapid approach of an ill-defined Brexit, the UK needs concrete plans, not wishful thinking.

Imports from the rest of the world will almost certainly be less safe and of lower quality than the EU delivers. The EU has some of the highest food safety standards in the world, even though there remains some room for improvement. Food safety standards in the USA are significantly lower than those in the EU, and standards in most developing countries are significantly below those that prevail in the USA.

There has been much talk of the UK reaching a free trade deal with the USA, which would allow the US to sell all and any of its food and drink products in the UK. The proposal has provoked debates about ‘chlorine-washed chicken’. That discussion focussed on just a fraction of the differences between EU and US food standards. Firstly, in the USA chlorinated water is only one of six types of chemical disinfectant that can lawfully be applied not just to chickens, but also to turkeys, as well as other meats and fish, fruits and vegetables. While the US authorities have deemed those ‘pathogen reduction treatments’ to be acceptably safe, they have done so only by reference to very modest amounts of data, and have ignored both evidence of risks and large gaps in the available data. The EU permits only one of those treatments, namely peracetic acid (which is a mixture of acetic acid and hydrogen peroxide) and then only for washing chicken carcasses, but not cuts of meat, and for no other species of meat, fish or vegetables. The EU approach is to require better hygiene in livestock production, abattoirs and meat-cutting plants rather than washing dirty meat with disinfectant.

There are several other respects in which the US food supply is less safe than the EU’s. In November 2017 Sustain, the UK alliance for better food and farming, reported that the sales of antibiotics to livestock farmers had risen by 27% in the USA since 2009, whereas UK farmers had reported a 26% reduction. The overuse of antibiotics in agricultural livestock and their residues in foodstuffs are contributing to the development of antibiotic-resistant infections, and if medical antibiotics are not to lose their effectiveness before new alternatives are developed, the medical and veterinary use of antibiotics must be more tightly controlled, not liberalised.

Another respect in which US food standards are significantly below those of the EU concerns the use of synthetic hormones. Most US beef cattle receive implants of growth-promoting hormones under their skin in an effort to make them gain weight faster. Those hormones are not permitted in the EU, and US beef from treated cattle cannot lawfully be imported into the EU. The US authorities claim the use of those hormones is acceptably safe, but they have only assessed risks to average healthy adults. The EU approach recognises that not all Europeans are average, healthy or adult, and EU scientific advisors have highlighted risks to infants, pre-pubescent adolescents and to those who are immunologically compromised.

US farmers also inject their dairy cows with a synthetic hormone that increases milk production, per unit of feed, but EU scientists have recognised that the treatment results in higher levels of mastitis, in infected udders, which results in a higher ‘somatic cell count’ (i.e. more pus) in the milk and greater use of antibiotics. Consequently that practice is not lawful in the EU, and nor is the import of milk or dairy products from the USA, unless they can be reliably certified as coming from from untreated cows.

Very similar considerations apply to genetically-modified (GM) foods. GM crops are grown very widely in the USA, and almost all soya beans and maize produced in the USA is GM. It would be unrealistic to expect UK consumers to become enthusiastic about GM foods, just because of Brexit. Furthermore, GM ingredients do not have to be declared on food labels in the USA, and doubtless the US would try to insist that the UK changed its labelling rules to match those in the USA, rather than conforming to EU rules.

If the UK were to complete a free trade deal with the USA after Brexit which included food products, not merely would the USA be able to sell its products in the UK, but UK producers would demand the right to use the same technologies – invoking arguments for a ‘level playing field’.

A food system can only be said to be ‘secure’ if it provides sufficiency, sustainability, safety, health and equity. Brexit represents a threat to all of each of these. Those risks could be substantially reduced if the UK were to stay in the Single Market or the Customs Union, or both, but that is not the direction in which the UK government says it wants to go.

This post represents the views of the author and not those of the Brexit blog, nor the LSE. A fuller exploration of the food security issues surrounding Brexit can be found in a paper co-written by the author, A Food Brexit: time to get real: a Brexit Briefing (T Lang, E Millstone & T Marsden), University of Sussex.

Erik Millstone is Emeritus Professor of Science Policy at the Science Policy Research Unit, University of Sussex.