Charoen Pokphand Foods farms prawns in Thailand and supplies frozen products to stores across the globe including Aldi and Tesco.
An investigation by The Guardian newspaper found some of the fishmeal used to feed the firm’s prawns in Thailand was sourced from suppliers who bought and sold large numbers of men as slaves.
In a statement, CPF UK said slavery was endemic in Thailand’s supply chain and all producers in the region were effected because there was no proper oversight of activities on fishing boats.
“As purchasers of fishmeal, CP Foods has been actively working to solve this problem since April 2013 and will continue to do so.
“We are now in the process of auditing our entire operation so that we can introduce an independent spot-check system across our supply chain to ensure it is and continues to be slavery free,” it said.
The company’s managing director in Britain, Bob Miller, said it would not defend what was happening in Thailand but that 75% of its suppliers in the country were certified.
The company said since 2013, it has been working with the Thai authorities to improve practices in its fishing industry.
The investigation recounted the experiences of Cambodian and Burmese boatmen who were sold for as little as €310 to trawler captains in the seas of South East Asia.
The men worked for 20-hour shifts, were beaten and tortured, and were kept at sea for extended periods.
They had to fish for species that when landed was converted into fishmeal and sold on to companies like CP to feed farmed prawns.
Although Ireland fishes its own prawns traditionally the domestic market prefers warmer-water varieties frozen and shipped from south east Asia.
This means much of the domestic product, which is a different species, is exported and companies such as CP produce the product on shelves and in freezer aisles.
Tesco and Aldi both released statements yesterday to say they did not support slavery in the supply chain.
Tesco said it regarded slavery “as completely unacceptable”.
“We are working with CP Foods to ensure the supply chain is slavery-free,” it said.
Aldi said it would “not tolerate” practices which violate human rights.