Claims by Boris Johnson that regulations imposed by “Brussels bureaucrats” were damaging the trade in kippers have been debunked by the European commission, which said that the food safety obligations criticised by him were due to rules set by Britain.

Speaking during the final hustings of the Conservative party’s leadership contest on Wednesday night, Johnson held aloft a plastic-wrapped kipper that had come from a fish smoker on the Isle of Man, who he said was “utterly furious”.

“After decades of sending them through the post like this he has had his costs massively increased by Brussels bureaucrats who are insisting that each kipper must be accompanied by a plastic ice pillow,” said the MP, who added that it had been presented to him by the editor of a national newspaper.

“Pointless, pointless, expensive, environmentally damaging ‘elf and safety’,” Johnson added.

However, the European commission hit back against the claims on Thursday, pointing to British government advice, which stresses that foods that need refrigerating must be kept cool while they are being transported – potentially packed in an insulated box with a coolant gel or in a coolbag.

A spokesperson for the commission said that while traders had an obligation to meet microbiological requirements to ensure the safety of food, the sale of products from food businesses to consumers was not covered by EU legislation on food hygiene.

“The case described by Mr Johnson falls outside the scope of the EU legislation and it’s purely a UK national competence, so I hope this is clear and the rules must be checked with the national authorities,” a commission spokesperson said during a briefing to journalists on Thursday.

“There are strict rules when it comes to fish, but these kinds of rules do not apply to processed fishery products. I’m talking about the temperature case that he was explaining.”

To cheers and laughter from the party faithful during the hustings at the ExCel Centre in London, Johnson had appeared to riff on the political nickname for Ukip, once feared by Conservative leaders, telling the crowd: “We will bring the kippers back. It’s not a red herring.”