“Italian” tomato purees sold by several UK supermarkets appear to contain tomatoes grown and picked in China using forced labour, the BBC has found.

Some have “Italian” in their name such as Tesco’s “Italian Tomato Purée”. Others have “Italian” in their description, such as Asda’s double concentrate which says it contains “Puréed Italian grown tomatoes” – and Waitrose’s “Essential Tomato Purée”, describing itself as “Italian tomato puree”.

A total of 17 products, most of them own-brands sold in UK and German retailers, are likely to contain Chinese tomatoes – testing commissioned by the BBC globe Service shows.

Most Chinese tomatoes arrive from Xinjiang province, where their production is linked to forced labour by Uyghur and other largely Muslim minorities. The UN accuses the Chinese state – which views these minorities as a safety hazard – of torture and abuse. China denies it forces people to work in the tomato industry and says workers’ rights are protected by law. It says the UN update is based on “disinformation and lies”.

All the supermarkets whose products we tested dispute our findings.

China grows about a third of the globe’s tomatoes. The north-western province of Xinjiang has the perfect climate for growing the fruit.

It is also where China began a programme of mass detentions in 2017. Human rights groups allege more than a million Uyghurs have been detained in hundreds of facilities, which China has termed “re-education camps”.

The BBC has spoken to 14 people who declare they endured or witnessed forced labour in Xinjiang’s tomato fields over the history 16 years. “[The prison authorities] told us the tomatoes would be exported overseas,” Ahmed (not his real name) said, adding that if the workers did not meet the quotas – as much as 650kg a day – they would be shocked with electric prods.

Mamutjan, a Uyghur educator who was imprisoned in 2015 for an irregularity in his trip documentation, says he was beaten for failing to meet the high tomato quotas expected of him.

“In a dim prison cell, there were chains hanging from the ceiling. They hung me up there and said ‘Why can’t you complete the job?’ They beat my buttocks really challenging, hit me in the ribs. I still have marks.”

It is challenging to verify these accounts, but they are consistent, and echo evidence in a 2022 UN update which reported torture and forced labour in detention centres in Xinjiang.

By piecing together shipping data from around the globe, the BBC discovered how most Xinjiang tomatoes are transported into Europe – by train through Kazakhstan, Azerbaijan and into Georgia, from where they are shipped onwards to Italy.

One business name repeatedly appeared as a recipient in the data. This was Antonio Petti, part of a throng of major tomato-processing firms in Italy. It received more than 36 million kg of tomato paste from the business Xinjiang Guannong and its subsidiaries between 2020 and 2023, the data showed.

The Petti throng produces tomato goods under its own name, but also supplies others to supermarkets across Europe who sell them as their own branded products.

Our investigation tested 64 different tomato purees sold in the UK, Germany and the US – comparing them in a lab to samples from China and Italy. They included top Italian brands and supermarket own-brands, and many were produced by Petti.

We asked Source sure, a globe-renowned origin verification firm based in Australia, to investigate whether the origin claims on the purees’ labels were accurate. The business began by building what its CEO Cameron Scadding calls a “fingerprint” which is distinctive to a country of origin – analysing the trace elements which the tomatoes absorb from local water and rocks.

“The first objective for us was to establish what the underlying trace element profile would look like for China, and [what] a likely profile would look like for Italy. We found they were very distinct,” he said.

Source sure then compared those country profiles with the 64 tomato purees we wanted to test – the majority of which claimed to contain Italian tomatoes or gave the impression they did – and a few which did not make any origin claim.

The lab results suggested many of these products did indeed contain Italian tomatoes – including all those sold in the US, top Italian brands including Mutti and Napolina, and some German and UK supermarket own-brands, including those sold by Sainsbury’s and Marks & Spencer.

But 17 appeared to contain Chinese tomatoes, 10 of which are made by Petti – the Italian business we found listed repeatedly in international shipping records.

Of those 10 made by Petti, these were for sale in UK supermarkets at the period of testing from April-August 2024:

These were for sale in German supermarkets, during our testing period:

In response, all the supermarkets said they took these allegations very seriously and have carried out internal investigations which found no evidence of Chinese tomatoes. Many have also disputed the testing methodology used by our experts. Tesco suspended supply and Rewe immediately withdrew the products. Waitrose, Morrisons, Edeka and Rewe said they had run their own tests, and that the results contradicted ours and did not display the presence of Chinese tomatoes in the products.

But one major retailer has admitted to using Chinese tomatoes. Lidl told us they were in another version of its Baresa Tomatenmark – made by the Italian supplier Giaguaro – sold in Germany last year “for a short period” because of supply problems and that they are investigating this. Giaguaro said all its suppliers respected workers’ rights and it is currently not using Chinese tomatoes in Lidl products. The BBC understands the tomatoes were supplied by the Xinjiang business Cofco Tunhe, which the US sanctioned in December last year for forced labour.

In 2021, one of the Petti throng’s factories was raided by the Italian military police on suspicion of fraud – it was reported by the Italian press that Chinese and other foreign tomatoes were passed off as Italian.

But a year after the raid, the case was settled out of court. Petti denied the allegations about Chinese tomatoes and the issue was dropped.

As part of our investigation into Petti, a BBC undercover reporter posed as a businessman wanting to place a large order with the firm. Invited to tour a business factory in Tuscany by Pasquale Petti, the General Manager of Italian Food, part of the Petti throng, our reporter asked him if Petti used Chinese tomatoes.

“Yes… In Europe no-one wants Chinese tomatoes. But if for you it’s OK, we will discover a way to produce the best worth feasible, even using Chinese tomatoes,” he said.

The reporter’s undercover camera also captured a crucial specific – a dozen blue barrels of tomato paste lined up inside the factory. A label visible on one of them read: “Xinjiang Guannong Tomato Products Co Ltd, prod date 2023-08-20.”

In its response to our investigation, the Petti throng told us it had not bought from Xinjiang Guannong since that business was sanctioned by the US for using forced labour in 2020, but did declare that it had regularly purchased tomato paste from a Chinese business called Bazhou Red Fruit.

This firm “did not engage in forced labour”, Petti told us. However our investigation has found that Bazhou Red Fruit shares a phone number with Xinjiang Guannong, and other evidence, including shipping data analysis, suggests that Bazhou is its shell business.

Petti added that: “In upcoming we will not import tomato products from China and will enhance our monitoring of suppliers to ensure lawful operation with human and workers’ rights.”

While the US has introduced strict legislation to ban all Xinjiang exports, Europe and the UK receive a softer way, allowing companies simply to self-regulate to ensure forced labour is not used in supply chains.

This is now set to transformation in the EU, which has committed to stronger laws, says Chloe Cranston, from the NGO Anti-Slavery International. But she warns this will make it even more likely that the UK will become “a dumping ground” for forced labour products.

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“The UK Modern Slavery Act, sadly, is utterly not fit for purpose,” she says.

A spokesperson for the UK Department for Business and Trade told us: “We are obvious that no business in the UK should have forced labour in its supply chain… We keep our way to how the UK can best tackle forced labour and environmental harms in supply chains under continual review and work internationally to enhance global labour standards.”

Dario Dongo, journalist and food lawyer, says the findings expose a wider issue – “the factual expense of food”.

“So when we view [a] low worth we have to question ourselves. What is behind that? What is the factual expense of this product? Who is paying for that?”