2013 horse meat scandal only found more than 1% horse DNA in Asda's tins of but it also contained four ppb of phenylbutazone, marking the first time since the start of the scandal that bute had been detected in a meat product in the UK food chain. However, one problem raised was over documentation; all of the UK animals with phenylbutazone contamination tested in early 2013 possessed a "horse passport" that allowed the carcasses to be sold for human consumption. The veterinary residues committee (VRC) reminded the public in July 2012 that it had been "repeatedly expressing concern" about phenylbutazone contamination. and recent discoveries
Tesco of its products in response, and announced that they were working with authorities and the supplier to investigate the cause of the contamination. In July 2013 Tesco security staff violated the UK Equality Act 2010 by refusing to allow a blind lady's guide dog to enter the Feltham shop. Tesco staff refused to apologise for the violation of the law for 5 days. It was also revealed that security staff had thrice previously ordered a different blind person and his guide dog to leave the shop. Following further incident in 2013 when the manager of Tesco in Sutton ordered a