MEXICO CITY (AP) - Food manufacturers promised Mexico's government on Wednesday that they would freeze prices on more than 150 food products to help families cope with rising costs.

President Felipe Calderon said prices for goods such as beans, canned tuna, fruit juices, coffee, ketchup and canned tomatoes will remain fixed until Dec. 31.

"This is a measure that will positively and directly benefit the finances of millions of Mexicans," said Calderon, flanked by representatives of Mexico's business chambers. "This reflects the commitment of Mexican businessmen to the country and to price stability."

The Mexican leader has blamed high food costs on rising global energy prices, soaring food demand in China and India and the use of corn for ethanol production.

Food prices, especially rice, have reached historic highs almost everywhere in the world.

Some Mexican shoppers felt the price freeze came too late to do much good.

"Six months? And what happens after that?" said Petra Castaneda, a 55-year-old retired civil servant who was leaving one grocery store empty handed to seek a better deal for cheese elsewhere. She said hearing Calderon's announcement over the radio only infuriated her more.

"All the prices have already risen, it would be ridiculous if they rose even more. Of course they freeze them now," she said.

Calderon, a conservative elected in 2006, has taken several steps to fight high prices. He eliminated import tariffs on several foodstuffs in May, won an agreement from rice farmers to sell their crop at 10 percent below international market prices and last year imposed price caps on tortillas, Mexico's staple food.

He also announced small monthly cash subsidies to 26 million poor Mexicans, about a quarter of the population. The cash payments of about 120 pesos ($11.6) a month are expected to cost about $433 million.

Mexico's central bank said annual inflation rose to 4.95 percent in May, the fastest pace in more than three years, led by the swelling costs of food oils, rice, wheat products and corn tortillas. The country's daily minimum wage is about 50 pesos ($4.80).

The six-month freeze was voluntary. Mexico's main food industry association, CONAINCA, cautioned it would only be maintained "as long as there were no extraordinary upsets in the national economy."

Cooking oil and flour will only stay at current prices if production costs remain stable, said Ismael Plascencia Nunez, the president of Mexico's Chamber of Industries.

Sidney Weintraub, an economist with the Washington-based Center for Strategic and International Studies, said reaching an agreement with businesses could spare Mexico some of the risks that often accompany mandatory price controls - such as shortages. But he cautioned there was nothing to keep prices from skyrocketing once companies decide they can no longer afford fixed prices.

"It's palliative. There's absolutely no assurance that other prices will be lower six months from now," Weintraub said.