By Richa Naidu LONDON (Reuters) – European retailers are locked in extended price negotiations with giant food companies – including the world’s biggest, Nestle – as they fight to retain shoppers and protect their profits. Major consumer products companies across the world have announced plans to boost prices at a faster pace than last year as they too seek to curb the impact of soaring raw materials costs on their margins. European Central Bank President Christine Lagarde early this month flagged rising food prices as a significant contributor to January’s unexpectedly high overall inflation …