By Xiaoyi Shao and Kevin Yao

BEIJING (Reuters) - China's annual inflation climbed to an eight-month high of 3.2 percent in October as food costs soared, fanning market worries about policy tightening as factory output and investment data pointed to signs of stabilization in the economy.

Inflation, which quickened slightly from 3.1 percent in September, was still lower than a median forecast of 3.3 percent in a Reuters poll and was below the official target of 3.5 percent for 2013.

"Although the CPI inflation was mainly pushed up by seasonal food demand, it may fuel market concerns that the central bank may tighten monetary conditions," said Li Huiyong, an economist at Shenyin & Wanguo Securities in Shanghai.

The People's Bank of China refused to inject liquidity into the money markets during regular open market operations on Thursday, triggering worries it would start a new round of tightening in the next few months, traders said.

Data on Friday showed exports rebounded by more than expected in October, adding to signs the economy has found its footing as Beijing prepares its reform agenda for the next decade.

But few analysts believe the central bank will rush to tighten policy amid the lingering global uncertainties.

The PBOC has said it will maintain its prudent policy-setting with timely fine-tuning to keep the economy on an even keel while warding off inflationary risks.

The National Bureau of Statistics said food prices rose 6.5 percent in October from a year earlier, quickening from 6.1 percent in September.

China's producer prices fell 1.5 percent last month from a year earlier - the 20th consecutive month of decline - versus a fall of 1.3 percent the previous month, the bureau said.

Economists polled by Reuters had expected consumer inflation of 3.3 percent and factory-gate prices to decline 1.4 percent.

Month-on-month, consumer prices were up 0.1 percent versus a rise of 0.2 percent expected by economists. Producer prices in October were unchanged from the previous month.

NO TIGHTENING SEEN

Data from the National Bureau of Statistics also showed China's factory output rose 10.3 percent in October from a year earlier, beating market expectations of 10 percent.

Fixed-asset investment, a key driver of economic growth, climbed 20.1 percent in the first 10 months from a year earlier - in line with forecasts. Real estate investment growth rose 19.2 percent, while revenue from property sales rose 32.3 percent.

Retail sales, a key gauge of consumption, were up 13.3 percent in October from a year earlier, versus 13.4 percent expected by the market.