Closer trade links between the UK and the US after Brexit could be derailed by the loss of a series of complex US-EU commercial agreements covering aviation, food and duties on whisky among other things, a campaign group has said.

Open Britain, a collection of MPs and other campaigners battling against a hard Brexit, said it had identified 19 bilateral and multilateral agreements connected to commercial matters which could be in jeopardy.

The campaign says these will be lost once Brexit happens in 2019, unless there is the opportunity and time for the UK to sign replacement deals with the US, or be permitted to stay within the existing EU-based arrangements.

The promise of reinvigorated trade with the US has been high on the list of priorities for Brexit’s leading lights, with Theresa May making a swift visit to see Donald Trump following his election last year.

In July the UK international trade secretary, Liam Fox, used his first overseas trip since the general election to travel to Washington and, as his department put it, “explore ways to deepen trade and economic links” between the nations.

But the trip was overshadowed by a row over whether a new US-UK trade deal would oblige Britain to allow the import of food products such as chlorine-washed chicken, something Fox said the media seemed “obsessed” by.

Agriculture, food and drink feature heavily among the19 US-EU agreements highlighted by Open Britain, including a fisheries convention for the north-west Atlantic, public health guarantees for beef, veal and pork, and agreements over the trade in bananas and duties on whiskies, gin and other spirits.

Other arrangements highlighted by the group cover wine, rice, cereals and and livestock. Another area highlighted by the group is the Open Skies deal, in force since 1992, which establishes a single aviation market between the EU and the US, allowing competition without restriction.

Among the 19 deals are some that cover more general areas, such as customs arrangements and competition.

Open Britain argues that the government must outline its plans to retain these agreements after Brexit and guarantee any new trade deal would not result in worse terms. It is also asking for details of contingency planning for the possibility that the UK loses any of these agreements.

Pat McFadden, a Labour MP who backs Open Britain, said: “Before the government cosies up any closer to President Trump in its desperation to get a trade deal with the United States, we should secure the agreements we already have with them through our membership of the European Union.

“If we do not retain these agreements after Brexit, the consequences for the British economy will be dire in sectors from aviation to agriculture. We all want Britain to have the freest trade possible with the United States, so long as doing so does not compromise our workers’ rights, consumer protection and environmental standards.”

An international trade spokeswoman said: “The first priority of the UK-US trade and investment working group discussions, which opened last month, is to give businesses on both sides of the Atlantic certainty and confidence as we leave the EU.

“As an international economic department, we will aim to ensure commercial certainty for US and UK businesses by working to secure continuity of existing EU-US agreements, such as the air transport agreement”.

• This article was amended on 29 August 2017 to include a quote from an international trade spokeswoman.