FSA says move could affect several British businesses, but Dutch officials say there is no health risk

Fifty thousand tonnes of meat destined for human consumption has been recalled by Dutch authorities in a move that could draw in several British businesses, according to officials at the UK's Food Standards Agency.

Investigators in the Netherlands said the origin of the meat at Wiljo Import and Export and Vleesgroothandel Willy Selten was unclear. Dutch officials said 130 companies in the Netherlands and 370 more across Europe were affected by the recall, and there is no health risk at this point.

On Tuesday Asda recalled tens of thousands of cans of corned beef after finding traces of the veterinary painkiller phenylbutazone, commonly known as bute. It is illegal for bute to enter the food chain.

The FSA has also revealed that 22 horses slaughtered for food at UK abattoirs since the end of January – one in 50 of the total – tested positive for bute.

In all, 1,042 horses have been tested since the new regime of 100% testing was introduced. The government says the bute presents a very low risk to human health. Most of the positive tests have been found since mid-February, when ministers said no carcasses could leave abattoirs until tests had proved they were clear of the drug.

The developments are likely to fuel concerns that meat contamination scandal is not over, even though the corned beef is the only product so far to have tested positive for bute having previously been found to contain more than 1% horsemeat. Twenty-four products have so far been named in industry tests.

Sales of frozen burgers and ready meals continued to slump last month. Frozen burger sales were down 32% in the four weeks to 17 March compared with the same period a year before, according to the research firm Kantar Worldpanel. That was a slight improvement from the 43% slump recorded in February. Frozen ready meal sales continued to drop by 12% in March, the same pace as in February.

The extra precautions on releasing carcasses after slaughter were introduced after David Heath, the food and agriculture minister, revealed that six out of eight carcasses tested in the first weeks of the scheme had tested positive and six may have entered food in France. He called the presence of bute unacceptable and said anyone found to have broken the law would be dealt with.

The Department for Environment, Food and Rural Affairs said on Tuesday: "Horse owners are legally responsible for keeping a passport that records the veterinary medicines it has received. Obtaining and using a fraudulent passport is an offence and could lead to a fine of up to £5,000."

Mary Creagh, the shadow environment secretary, said tougher rules should be imposed on the food industry. "A lot of these products are long-life or frozen so they stick around in people's cupboards and freezers for up to a year. Every product found to be contaminated with horsemeat from the beginning of the scandal should be recalled and we should be absolutely clear about what those products are."

Creagh said the FSA should have publicised a central list of affected products that could be easily accessed by worried shoppers. "Some supermarkets have been clear about it and some have not," she said.

Richard Lloyd, the executive director of Which?, said the continuing scandal exposed the need for urgent changes to the way food fraud was detected and standards enforced. "These serious failings must be put right if consumers are to feel fully confident in the food they are buying once more. Ministers must ensure that everyone involved, including their own departments, the FSA, the food industry and local authorities, are crystal clear about their responsibility to protect consumers and are properly equipped to do so."

Tesco's and Asda's websites name all the products they have tested and those that failed, but several rivals are more coy about the number of items that have been withdrawn from sale or even found to contain horsemeat.

Aldi's website gives a high profile to information about its use of British meat but apparently fails to mention that two of its frozen ready meals were found to contain horsemeat.

The Co-operative's website gives prominence to a piece stating that "our latest tests on all our own-brand minced beef products have been confirmed as containing beef and only beef". The fact that it found horsemeat in some of its own-label frozen burgers is hidden away at the bottom of a press release titled: "Meat testing – a few words of reassurance."

• This article was amended on 12 April 2013. The original said "Forty-four products have so far been named in industry tests." While 44 tests showed that beef products contained at least 1% horsemeat, there were multiple tests on some products; so far, 24 products have been named as containing at least 1% horsemeat.