By Richa Naidu LONDON (Reuters) -Carrefour says it has ditched Pepsico products in four European countries for taking price hikes too far, but the negotiation tactic may have little impact given the size of some global brands, industry experts said. The strategy of removing products from shelves is one retailers have employed for years in the tussle over prices with suppliers, but the cost-of-living crisis has prompted more disputes, such as a reported spat between German retailer Edeka and U.S. Procter & Gamble last year. Supermarkets, who are operating on razor-thin margins, say they are try…