The world's biggest food group Nestle has reported rising sales but says it is having a "challenging year".

世界最大的食品集团雀巢公司第一季度销售额增长，但是称2012年是“充满挑战的一年”。

The Swiss company said its sales in the first three months of 2012 were 21.4bn Swiss francs ($23.4bn; £14.6bn), up 5.6% from the same period last year.

The group behind KitKat and Nespresso said that the trading environment had been subdued¹ in many developed markets.

But it added that in most emerging markets "conditions remain dynamic（动态的） and rich in growth opportunities".

Nestle struggled in 2011 with the strength of the Swiss franc, which cut its earnings² by 13.4% in the full year.

But in the past six months the Swiss central bank has been intervening to weaken its currency and support the country's exporters.

Nestle said an expected "improved raw material environment" in the second half of the year together with rising prices meant it could maintain its forecast of improved earnings and profit margins³ for the full year.

It did not comment on the deal it is expected to finalise this month to buy Pfizer's infant nutrition business for about $9bn (£5.6bn).