Tesco has revamped its upmarket Finest food range in an effort to turn UK sales around.The supermarket chain said it is spending tens of millions of pounds on launching more than 400 new products and re-launching existing products."Finest is Tesco's flagship food brand and our aim with today's relaunch is simple - to be the best product on the market," Tesco UK Managing Director Chris Bush said in a statement on Monday."It is already the fastest growing premium brand in the market, and we've reviewed every product in the range to be sure it's fit to carry the Finest brand."The news came as Moody's downgraded its outlook for the supermarket chain from 'stable' to 'negative'. The credit-rating agency pointed to concerns over the retailer's performance in the UK after it posted weak first-half profits last week.Tesco has been trying to rework its image following a scandal over traces of horsemeat found in its beef-based products. Shares fell 0.48% to 360.25p at 14:32 on Tuesday.RD