In its first quarterly results since its July flotation, food outlet operator SSP reported a 1.4% drop in sales in the quarter to the end of June, due to the impact of currency headwinds.It is the latest in a string of companies to be hurt by the strength of sterling against other key currencies including the euro and the US dollar.However, on a constant currency basis, the firm's sales were up by 3.5% from April to June 2014 as it said it "continues to benefit from good passenger growth in its core travel markets".SSP saw sales grow between April and June due to strong performance in the UK, North America and Asia Pacific regions. The group received a £135m contract at London Stansted Airport in July and an $80m 10-year contract at Sacramento Airport in June 2014.The international group operates brands including Starbucks, Burger King, Upper Crust or Millie's Cookies.SSP's chief executive, Kate Swann, said: "I am pleased to announce our first IMS as a listed company. During the period we saw a strong performance for the Group, particularly in the U.K., North America and Asia Pacific. We continue to be confident in the outlook for the business."The company's shares were up 0.11% to 230p on Thursday at 11:45.JF