Federal investigators said today some food prices have risen faster than warranted by the drought but a Senate chairman said there's no proof so far of significant price gouging. ``Some price increases do appear higher than warranted by the drought alone,'' Sen. Patrick J. Leahy, D-Vt., told a hearing of his Senate Agriculture Committee. He said the higher levels were ``most notably in wheat-based food products, such as pasta and bread, and in some meats.'' ``But in general there do not seem to have been excessive price increases across a broad range of products that use the drought as an excuse,'' he said. The hearing was held to unveil a report from the General Accounting Office on food price increases between July and August. The report was requested by Leahy and Rep. Byron Dorgan, D-N.D., in July amid speculation that the food industry would seize on the drought to hike prices. A General Accounting Office official, John Harman, told the committee some price increases found by the congressional investigative agency could not be explained by the drought. He pointed to a 6 percent jump in pasta prices between the July and August checks that the agency made. A rise of 3.4 percent would be warranted by the impact of the drought on durham wheat used to make pasta, he said. He added that cattle prices dropped as a result of the drought but that was not reflected by the cost of beef. Just why there were some unexplained increases was unclear, he said. It may have been because ``prices of packaging of food products went up significantly this year,'' GAO aide Mary Kenney told the panel. ``There could have been some labor cost increases ... we don't know if there were,'' Harman said. ``Conclusive evidence of price gouging has not been found but there are some indications out there'' that suggest it could materialize in the future, Sen. Tom Harkin, D-Iowa, told the hearing packed with lobbyists from the nation's multi-billion-dollar food industry. ``My advice to consumers is to be comparative shoppers,'' he said. ``Food processors and retailers need to know that we are all watching and they must be held accountable for any food price increases not directly attributable to higher costs,'' Leahy and Dorgan said in a statement released Tueslday night. The study showed that the price of ground beef has increased 3 percent, while the price that livestock producers get for cattle actually has dropped 11 percent since April. Rising feed prices have accelerated the sale of cattle and thus created a buyers' market. Fruit prices rose an average of 12 percent, while bread prices increased 4 percent, according to the GAO. The lawmakers stressed that the GAO figures represented national averages and that there could be differences from one region to another. Two consumer organizations issued a report on Monday saying there had been no ``price gouging'' in July and August but ``substantial'' increases in beef and some other agricultural goods in June. The report was issued jointly by the Consumer Federation of America and Washington-based advocacy group, Public Voice on Food, Health and Policy.