The practice of smuggling sick cows into the meat chain is feared to be more widespread in Poland than previously believed, according to the investigative reporter who captured footage of ill cows being dragged to slaughter with a winch.

After Patryk Szczepaniak’s undercover footage aired, the EU’s rapid alert system for food and feed was triggered, and it has since been confirmed that meat from this particular abattoir was exported to 12 other EU countries (not including the UK).

The Polish authorities have since shut down the slaughterhouse, and EU officials will travel to Poland on Monday to monitor events.

But Szczepaniak has challenged claims by the Polish veterinary authorities that the scandal was an isolated incident, citing evidence of a much wider black market in meat from sick cows operating across Poland.

Szczepaniak, a reporter with Superwizjer, a Polish investigative TV programme broadcast on news channel TVN24, infiltrated the slaughterhouse late last year and worked there undercover for almost three weeks. He captured footage showing cows so sick that they were unable to stand up being dragged out of trucks and into the slaughterhouse using a winch, with ropes tied around their horns or legs.

The slaughter of sick cows took place at night with no veterinary officials on site, in another contravention of basic standards. Workers at the slaughterhouse were tasked with removing evidence from the carcasses, such as pressure sores and tumours that indicate the cows were sick and had been lying on their sides for days on end.

On Thursday Poland’s chief veterinary official, Pawel Niemczuk, confirmed to reporters that authorities had identified 9.5 tonnes of beef originating from the slaughterhouse, 2.7 tonnes of which were exported to other EU countries. “I have convinced most of the countries that this situation in Poland was an individual case,” Niemczuk told a news conference, announcing that meat distributed from the slaughterhouse had been identified and withdrawn.

But Szczepaniak told the Guardian that since the programme was shown on Polish television last weekend he had received dozens of messages from around Poland from people claiming that similar practices were occurring in other parts of the country.

“My inbox is full of messages from people who live near slaughterhouses, former employees of slaughterhouses, former law-enforcement and regulatory officials, all claiming that similar things have been happening where they are. It has been a full-time job just following them all up – more is definitely going to come out about this,” he said.

This is not the first Polish slaughterhouse to be accused of involvement in the processing of sick cows. In December, the owner of a slaughterhouse near Łódź in central Poland was given a prison sentence for running a similar operation (he has appealed against his sentence). Prosecutors are also conducting an investigation into a slaughterhouse in eastern Poland.

Szczepaniak’s comments are likely to exacerbate concerns in other European countries. Meat from the slaughterhouse is understood to have reached Estonia, Finland, France, Hungary, Latvia, Lithuania, Portugal, Romania, Spain, Slovakia and Sweden. The European authorities are understood to have been alerted to the scandal two weeks after it was brought to the attention of Polish law enforcement officials.

“I urge the Polish authorities to finalise as a matter of urgency their investigations, taking all the necessary measures to ensure respect of the EU legislation including effective, rapid and dissuasive penalties against the perpetrators of criminal behaviour that could pose a risk to public health and portrays an unacceptable treatment of animals,’ Vytenis Andriukaitis, the EU commissioner responsible for food safety, said in a statement.

On Thursday Jozef Bíreš, head of Slovakia’s state veterinary and food administration, told reporters that 300 kilograms of meat from the slaughterhouse had been distributed to restaurants and schools in Slovakia.

The meat reached three distributors in Slovakia, with all of the meat understood to have gone to public catering facilities. One of the processing companies that received it is a supplier for major supermarkets in the country, including Tesco, although so far no evidence has emerged that any of the meat was distributed to any major supermarket chain.

Secret filming shows sick cows slaughtered for meat in Poland Read more

Slovakia’s agriculture minister, Gabriela Matečná, was reported as urging Slovaks not to eat Polish beef, saying that the scandal had discredited Poland’s veterinary regulator.

The Polish authorities have announced that CCTV will be installed in slaughterhouses and more health inspectors will be employed to improve the monitoring of slaughterhouse practices, as part of an initiative estimated to cost around 120 million zloty – about £25m.

Health experts sent by the European commission are due to arrive in Poland on Monday to monitor Warsaw’s response to the crisis.