The government has suffered defeats in the House of Lords in an ongoing tussle over post-Brexit food standards.
Peers struck down an amendment made by MPs last week to the Agriculture Bill.
It now returns to the Commons in the parliamentary "ping-pong" that happens when the two Houses can't agree.
Peers voted on Tuesday to ensure trade deals meet UK animal welfare and food safety rules, amid fears imports of chlorinated chicken and beef fattened with hormones will be allowed.
The government says it backs high food standards but does not want to include such guarantees in the Agriculture Bill, arguing that MPs will get a say when any post-Brexit regulations in trade deals come before Parliament.
But Labour's shadow environment minister Lord Grantchester said protections for the UK's high food standards need to be included in the Agriculture Bill.
Speaking during a debate on the bill, he told the Lords: "Future standards can be changed through technical statutory orders.
"We seek to put in primary legislation what the government has claimed is in the Withdrawal Act."
Tory peer the Earl of Caithness said: "The government has been unnecessarily obstructive and intransigent on this bill.
"And that is a huge sadness because they are alienating a lot of farmers and a lot of those who live in the country who see the government as being unnecessarily reluctant to accept any improvements to this bill."
Independent crossbencher Lord Curry of Kirkharle said: "The fear of cheap imported food undermining our standards of production as a result of trade deals that have not been adequately scrutinised has united all key stakeholders from the entire farming community."
Responding for the government, environment minister Lord Gardiner said the government was determined to have "a robust and positive relationship with the people who are custodians and stewards of the land".
"That's why the relationship we need to forge through the Agriculture Bill and the environmental land management system is absolutely about that collaboration."
Peers backed a move aimed at ensuring agricultural and food imports meet equivalent benchmarks as British producers, including on animal welfare, environmental protection and food safety, by 282 votes to 244.
They also voted to require the secretary of state to report to Parliament on the impact of proposed future trade deals on maintaining agri-food standards, including food safety, the environment and animal welfare by 278 votes to 200.