WASHINGTON (AP) -- While some fear the worst drought in 25 years will send grocery prices soaring, Agriculture Secretary Tom Vilsack is more optimistic.

The agriculture chief says the cost to farmers is not the same as the cost to grocery shoppers. He says even if commodities prices were to double, "you would probably only see a half a percent to maybe as much as a percent increase in food costs."

And Vilsack says crop yields may not come up as short as some have suggested. He says the effects won't be known until harvest, but farmers have planted larger-than-usual crops this year to offset the effects of the drought.

The Obama administration has authorized $30 million to help crop and livestock producers in drought-stricken areas.