The row over chlorinated chicken is set to intensify with a warning that cheap imported food could threaten farm animal welfare standards after Brexit.
The claim, from a powerful House of Lords committee, follows criticism of Liam Fox's controversial plans to allow chlorine-washed chicken from the US into the UK .
The International Trade Secretary, visiting Washington to negotiate a US-UK trade deal, has accused the British media of being "obsessed with chlorine-washed chickens".
But peers claim a post-Brexit increase in imports from countries operating lower farm animal welfare standards could put UK producers at a competitive disadvantage.
The warning comes from the House of Lords' EU energy and environment sub-committee in a report on the impact of Brexit on farm animal welfare.
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"The UK has some of the highest farm animal welfare standards in the world and UK producers are rightly proud of those," said the sub-committee chairman and Liberal Democrat peer Lord Teverson.
"We see no reason why Brexit should diminish those, as long as the Government is aware of the challenges ahead and acts accordingly.
"We heard evidence of undeniable concern that opening up the UK market to free global trade poses a number of issues.
"The Government may find it hard to reconcile its free trade ambitions with its commendable desire for preserving high farm animal welfare standards.
"We heard overwhelming support for farm animal welfare standards to be maintained or improved.
"To help achieve that, we urge the Government to secure the inclusion of high farm animal welfare standards in any free trade agreements it negotiates after Brexit.
"Whilst Brexit provides the UK with the unique opportunity to review and potentially improve farm animal welfare standards, the Government will need to consider the effect of increasing standards on the competitiveness of UK producers as well the future trading relationship with the EU."
That would potentially mean cheap imports into the UK of chlorine-washed chicken, which is currently banned by the EU but is considerably cheaper than European-produced chicken.
During his Washington visit, Dr Fox was clearly irritated when he was asked in a post-speech Q&A if he would feel comfortable eating a chlorinated chicken.
"The British media are obsessed with chlorine-washed chickens, a detail of the very end stage of one sector of a potential free trade agreement," he said.
Dr Fox is reported to have said the Americans have been eating chlorinated chicken perfectly safely for years and that a meaningful trade deal must include agriculture.
But new Environment Secretary Michael Gove, who last week promised to deliver a "green Brexit", has insisted that British food standards should not be downgraded in any way.
And Mr Gove's predecessor, Leader of the Commons Andrea Leadsom, says poor quality imports could damage British farming.
Dr Fox was also ridiculed by Labour's shadow international trade secretary, Barry Gardiner.
"This just goes to show that you should never trust a Fox in your hen coop," said Mr Gardiner.
And James McGrory, executive director of the pro-Remain campaign group Open Britain, said it was time for Dr Fox to devour a chlorine-washed chicken
"If the International Trade Secretary wants the public to trust him, he needs to take the opportunity while he's in the US and devour a chlorine-washed chicken live on camera," said Mr McGrory.