Supermarket prices in metropolitan Washington rose less than 1 percent between September and October, the slowest rate of local food inflation since last spring.

Price decreases for fresh fruits, frozen prepared foods, fish and poultry contributed to the moderating trend, the Labor Department reported yesterday. c

Although grocery store and government officials all have warned that substantial food price increases are expected over the next year, the 0.7 percent gain in the past month here was in contrast with a 1.2 percent increase in September and monthly hikes of more than 2 percent since June.

Area grocery store prices had declined in April and May, partly because of intense local competition that was introduced by no-frills, limited-selection food retailers. In addition, Giant Food Inc. -- one of the two dominant local food chains -- installed a voluntary price freeze on 400 private-lable products and some food and dairy items.

But prices rebounded sharply in June, jumping 3.1 percent in a single month, and starting a steady run up of local food prices that has continued since. For the past 12 months, area food prices have risen about 12 percent.

From September to October, area cereal and bakery produce prices rose 2.3 percent compared with a national average increase of 1.4 percent. Other local price increases in the recent month were reported for fresh vegetables, beef, sugar, milk and eggs.

In the Baltimore metropolitan area, where food prices have increased 11.7 percent over the past year, the rate of increase in October was 0.2 percent.

Fresh fruits and vegetables declined from September, with apples, oranges, potatoes and lettuce all costing less. Increases in bread, doughnuts and sweet rolls, dairy products and meats offset the declining prices in the Baltimore area.

Supermarket price information for the local area is published monthly by the Bureau of Labor Statistics. Six times a year, BLS issues reports on overall consumer prices in the area. The next local consumer price index statistics will be published in late December.