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 biofuels, offering petrol-bioethanol and diesel-biodiesel blends instead of pure petrol and diesel at their petrol stations, and now offering Greenergy 100% biodiesel at many shops in the southeast of the United Kingdom. In 1998, Tesco and Esso (part of Exxonmobil) formed a business alliance that included several petrol filling stations on lease from Esso, with Tesco operating the attached shops under their Express format. In turn, Esso operates the forecourts and sells their fuel via the Tesco shop. As of 2013, there were 200 joint Tesco Express/Esso sites in the UK. In 2018, Tesco launched a separate budget chain, Jack's,