One of Tesco’s suppliers in the US has been reported by America’s biggest food workers’ union in the latest spat between the two organisations.

The United Food and Commercial Workers Union (UFCW) reported ready meals supplier 2 Sisters Food Group to a tribunal for the alleged unfair firing of six workers.

The union claims 2 Sisters Food Group, which supplies to Tesco’s Fresh & Easy convenience stores, fired the employees for attending a union meeting and filing complaints against managers.

This is the latest in a series of altercations between Tesco and UFCW. The union is angered at the retailer’s failure to recognise it following its attendance at Tesco’s AGM in June, as well as two letters written in support of the union by Democratic presidential nominee Barack Obama.

2 Sisters said it is “very committed” to its investment in its food-processing facility, saying it aims to create 400 jobs over the next four years.