Criticism of US food standards was “designed to reduce not increase trade”, Woody Johnson told the BBC.
US beef and chicken producers use processes not permitted in the EU, including rinsing chicken carcasses with chlorine.
But Mr Johnson said the UK should accept American meat as part of a post-Brexit trade deal.
“To get a robust trade arrangement, that lifts all boats, it has to include farming and farm products,” he said.
Whether the UK should allow imports of US-produced beef and chicken after it leaves the EU is among the most contentious trade questions.
He said Americans believed their food was “cost-effective and humane” and would have taken legal action if they felt there was anything wrong with the safety of their food.
“If I had my choice between chicken that was safe and clean and didn’t have campylobacter material and poisons on it… I would take the one that had been cleaned sufficiently,” he said.
Does the US have less food poisoning?
The ambassador defended the practice of treating meat with chlorinated water, telling the BBC that in the US, “we have the lowest levels of food poisoning”.
But that’s not what the US figures say. The most common bacteria in chicken that cause food poisoning are campylobacter and salmonella. According to the US Centers for Disease Control, there are 1.3 million illnesses from campylobacter and 1.2 million illnesses from salmonella a year. That means about four in every thousand people get sick.
In 2017 Public Health England, which pulls together data from across the UK, recorded 63,946 confirmed cases of infection from campylobacter and 10,089 infections from salmonella. That’s one in a thousand and 0.2 in a thousand people respectively.
So the US has four times as many confirmed cases of campylobacter per thousand people as the UK – and twenty times as many cases of salmonella. About 450 people die of salmonella a year in the US, whereas in the UK deaths are very rare.